From: Štěpán Balážik <stepan@isc.org>
Date: Wed, 4 Feb 2026 17:17:17 +0000 (+0100)
Subject: Make default_algorithm accessible through a fixture and method
X-Git-Tag: v9.21.19~15^2~11
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ef21b779124e2edea914b75a1f7bbf963fbaafb4;p=thirdparty%2Fbind9.git

Make default_algorithm accessible through a fixture and method

Importing pytest fixture trips up static analysis tools, so move
default_algorithm to conftest.py and use it instead of os.environ
accesses in various system tests.

For use outside test function, use Algorithm.default().
---

diff --git a/bin/tests/system/conftest.py b/bin/tests/system/conftest.py
index 089d5ed52cb..4e7a1d7b1a1 100644
--- a/bin/tests/system/conftest.py
+++ b/bin/tests/system/conftest.py
@@ -233,6 +233,11 @@ def control_port():
     return int(os.environ["CONTROLPORT"])
 
 
+@pytest.fixture(scope="module")
+def default_algorithm():
+    return isctest.vars.algorithms.Algorithm.default()
+
+
 @pytest.fixture(scope="module")
 def system_test_name(request):
     """Name of the system test directory."""
diff --git a/bin/tests/system/dnssec/tests_signing.py b/bin/tests/system/dnssec/tests_signing.py
index 949c0de8189..42932b1afe3 100644
--- a/bin/tests/system/dnssec/tests_signing.py
+++ b/bin/tests/system/dnssec/tests_signing.py
@@ -136,12 +136,12 @@ def test_expiring_rrsig(ns3):
     assert sigs
 
 
-def test_apex_signing():
+def test_apex_signing(default_algorithm):
     # check that DNAME at apex with NSEC3 is correctly signed
     msg = isctest.query.create("dname-at-apex-nsec3.example.", "TXT")
     res = isctest.query.tcp(msg, "10.53.0.3")
     sigs = [str(a) for a in res.authority if a.rdtype == rdatatype.RRSIG]
-    alg = os.environ.get("DEFAULT_ALGORITHM_NUMBER")
+    alg = default_algorithm.number
     assert any(f"NSEC3 {alg} 3 600" in a for a in sigs)
 
 
@@ -171,7 +171,7 @@ def test_occluded_data():
     isctest.check.rr_count_eq(res.answer, 4)  # A+RRSIG, NSEC+RRSIG
 
 
-def test_update_signing():
+def test_update_signing(default_algorithm):
     # minimal update test: add and delete a single record
     up = update.UpdateMessage("dynamic.example.")
     up.add("a.dynamic.example.", 300, "A", "73.80.65.49")
@@ -191,7 +191,7 @@ def test_update_signing():
     # check that the NSEC3 record for the apex is properly signed
     # when a DNSKEY is added via UPDATE
     key = keygen(
-        "-Kns3", "-q3fk", "-a", os.environ["DEFAULT_ALGORITHM"], "update-nsec3.example."
+        "-Kns3", "-q3fk", "-a", default_algorithm.name, "update-nsec3.example."
     )
 
     with open(f"ns3/{key}.key", "r", encoding="utf-8") as f:
@@ -416,7 +416,7 @@ def test_zonestatus_signing(ns3):
     assert when < sigs[0].expiration
 
 
-def test_offline_ksk_signing(ns2):
+def test_offline_ksk_signing(ns2, default_algorithm):
     def getfrom(file):
         with open(file, encoding="utf-8") as f:
             return f.read().strip()
@@ -498,9 +498,9 @@ def test_offline_ksk_signing(ns2):
         "-Pnone",
         "-Anone",
         "-a",
-        os.environ["DEFAULT_ALGORITHM"],
+        default_algorithm.name,
         "-b",
-        os.environ["DEFAULT_BITS"],
+        f"{default_algorithm.bits}",
         zone,
     )
     zsk_2_id = getkeyid(zsk_2)
@@ -557,9 +557,9 @@ def test_offline_ksk_signing(ns2):
         "-Pnone",
         "-Anone",
         "-a",
-        os.environ["DEFAULT_ALGORITHM"],
+        default_algorithm.name,
         "-b",
-        os.environ["DEFAULT_BITS"],
+        f"{default_algorithm.bits}",
         zone,
     )
     zsk_3_id = getkeyid(zsk_3)
diff --git a/bin/tests/system/dnssec/tests_validation.py b/bin/tests/system/dnssec/tests_validation.py
index 2c79f584f43..777bb693b1d 100644
--- a/bin/tests/system/dnssec/tests_validation.py
+++ b/bin/tests/system/dnssec/tests_validation.py
@@ -11,7 +11,6 @@
 
 from re import compile as Re
 
-import os
 import shutil
 import time
 
@@ -123,7 +122,7 @@ def test_adflag():
     isctest.check.noadflag(res2)
 
 
-def test_secure_root(ns4):
+def test_secure_root(ns4, default_algorithm):
     # check that a query for a secure root validates
     msg = isctest.query.create(".", "KEY")
     res = isctest.query.tcp(msg, "10.53.0.4")
@@ -132,9 +131,8 @@ def test_secure_root(ns4):
 
     # check that "rndc secroots" dumps the trusted keys
     key = int(getfrom("ns1/managed.key.id"))
-    alg = os.environ["DEFAULT_ALGORITHM"]
     response = ns4.rndc("secroots -")
-    assert f"./{alg}/{key} ; static" in response.out
+    assert f"./{default_algorithm.name}/{key} ; static" in response.out
     assert len(response.out.splitlines()) == 10
 
 
diff --git a/bin/tests/system/dnssec/tests_validation_managed_keys.py b/bin/tests/system/dnssec/tests_validation_managed_keys.py
index 082400b0001..54253df0aae 100644
--- a/bin/tests/system/dnssec/tests_validation_managed_keys.py
+++ b/bin/tests/system/dnssec/tests_validation_managed_keys.py
@@ -29,7 +29,7 @@ def getfrom(file):
         return f.read().strip()
 
 
-def test_secure_root_managed(ns4):
+def test_secure_root_managed(ns4, default_algorithm):
     # check that a query for a secure root validates
     msg = isctest.query.create(".", "KEY")
     res = isctest.query.tcp(msg, "10.53.0.4")
@@ -38,9 +38,8 @@ def test_secure_root_managed(ns4):
 
     # check that "rndc secroots" dumps the trusted keys
     key = int(getfrom("ns1/managed.key.id"))
-    alg = os.environ["DEFAULT_ALGORITHM"]
     response = ns4.rndc("secroots -")
-    assert f"./{alg}/{key} ; managed" in response.out
+    assert f"./{default_algorithm.name}/{key} ; managed" in response.out
     assert len(response.out.splitlines()) == 10
 
 
diff --git a/bin/tests/system/dnssec/tests_validation_multiview.py b/bin/tests/system/dnssec/tests_validation_multiview.py
index d3ea9e300bd..b1cac381123 100644
--- a/bin/tests/system/dnssec/tests_validation_multiview.py
+++ b/bin/tests/system/dnssec/tests_validation_multiview.py
@@ -11,8 +11,6 @@
 
 from re import compile as Re
 
-import os
-
 import isctest
 
 
@@ -50,10 +48,9 @@ def test_validator_logging(ns4):
         watcher.wait_for_line(pattern)
 
 
-def test_secure_roots(ns4):
+def test_secure_roots(ns4, default_algorithm):
     # check that "rndc secroots" dumps the trusted keys with multiple views
     key = int(getfrom("ns1/managed.key.id"))
-    alg = os.environ["DEFAULT_ALGORITHM"]
     response = ns4.rndc("secroots -")
-    assert f"./{alg}/{key} ; static" in response.out
+    assert f"./{default_algorithm.name}/{key} ; static" in response.out
     assert len(response.out.splitlines()) == 17
diff --git a/bin/tests/system/isctest/vars/algorithms.py b/bin/tests/system/isctest/vars/algorithms.py
index 5be34ff7d78..c0a2eed5c1b 100644
--- a/bin/tests/system/isctest/vars/algorithms.py
+++ b/bin/tests/system/isctest/vars/algorithms.py
@@ -61,6 +61,15 @@ class Algorithm(NamedTuple):
     dst: int
     bits: int
 
+    @classmethod
+    def default(cls):
+        return cls(
+            os.environ["DEFAULT_ALGORITHM"],
+            int(os.environ["DEFAULT_ALGORITHM_NUMBER"]),
+            int(os.environ["DEFAULT_ALGORITHM_DST_NUMBER"]),
+            int(os.environ["DEFAULT_BITS"]),
+        )
+
 
 class AlgorithmSet(NamedTuple):
     """Collection of DEFAULT, ALTERNATIVE and DISABLED algorithms"""
diff --git a/bin/tests/system/kasp/tests_kasp.py b/bin/tests/system/kasp/tests_kasp.py
index 87ecbcab240..cc041dff86c 100644
--- a/bin/tests/system/kasp/tests_kasp.py
+++ b/bin/tests/system/kasp/tests_kasp.py
@@ -22,7 +22,7 @@ import pytest
 
 from isctest.kasp import KeyProperties, KeyTimingMetadata, SettimeOptions
 from isctest.util import param
-from isctest.vars.algorithms import ECDSAP256SHA256, ECDSAP384SHA384
+from isctest.vars.algorithms import ECDSAP256SHA256, ECDSAP384SHA384, Algorithm
 
 import isctest
 import isctest.mark
@@ -129,10 +129,10 @@ KASP_INHERIT_TSIG_SECRET = {
 }
 
 
-def autosign_properties(alg, size):
+def autosign_properties(algorithm: Algorithm):
     return [
-        f"ksk {lifetime['P2Y']} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
-        f"zsk {lifetime['P1Y']} {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
+        f"ksk {lifetime['P2Y']} {algorithm.number} {algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
+        f"zsk {lifetime['P1Y']} {algorithm.number} {algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
     ]
 
 
@@ -353,9 +353,7 @@ def cb_remove_keyfiles(params, ksks=None, zsks=None):
                 "policy": "autosign",
                 "config": autosign_config,
                 "offset": -timedelta(days=30 * 6),
-                "key-properties": autosign_properties(
-                    os.environ["DEFAULT_ALGORITHM_NUMBER"], os.environ["DEFAULT_BITS"]
-                ),
+                "key-properties": autosign_properties(Algorithm.default()),
             },
             id="dnskey-ttl-mismatch.autosign",
         ),
@@ -365,9 +363,7 @@ def cb_remove_keyfiles(params, ksks=None, zsks=None):
                 "policy": "autosign",
                 "config": autosign_config,
                 "offset": -timedelta(days=30 * 6),
-                "key-properties": autosign_properties(
-                    os.environ["DEFAULT_ALGORITHM_NUMBER"], os.environ["DEFAULT_BITS"]
-                ),
+                "key-properties": autosign_properties(Algorithm.default()),
                 "additional-tests": [
                     {
                         "callback": cb_rrsig_refresh,
@@ -383,9 +379,7 @@ def cb_remove_keyfiles(params, ksks=None, zsks=None):
                 "policy": "autosign",
                 "config": autosign_config,
                 "offset": -timedelta(days=30 * 6),
-                "key-properties": autosign_properties(
-                    os.environ["DEFAULT_ALGORITHM_NUMBER"], os.environ["DEFAULT_BITS"]
-                ),
+                "key-properties": autosign_properties(Algorithm.default()),
                 "additional-tests": [
                     {
                         "callback": cb_rrsig_reuse,
@@ -401,9 +395,7 @@ def cb_remove_keyfiles(params, ksks=None, zsks=None):
                 "policy": "autosign",
                 "config": autosign_config,
                 "offset": -timedelta(days=30 * 6),
-                "key-properties": autosign_properties(
-                    os.environ["DEFAULT_ALGORITHM_NUMBER"], os.environ["DEFAULT_BITS"]
-                ),
+                "key-properties": autosign_properties(Algorithm.default()),
                 "additional-tests": [
                     {
                         "callback": cb_rrsig_refresh,
@@ -419,9 +411,7 @@ def cb_remove_keyfiles(params, ksks=None, zsks=None):
                 "policy": "autosign",
                 "config": autosign_config,
                 "offset": -timedelta(days=30 * 6),
-                "key-properties": autosign_properties(
-                    os.environ["DEFAULT_ALGORITHM_NUMBER"], os.environ["DEFAULT_BITS"]
-                ),
+                "key-properties": autosign_properties(Algorithm.default()),
                 "additional-tests": [
                     {
                         "callback": cb_remove_keyfiles,
@@ -438,8 +428,8 @@ def cb_remove_keyfiles(params, ksks=None, zsks=None):
                 "config": autosign_config,
                 "offset": -timedelta(days=30 * 6),
                 "key-properties": [
-                    f"ksk 63072000 {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent missing",
-                    f"zsk 31536000 {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
+                    f"ksk 63072000 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent missing",
+                    f"zsk 31536000 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
                 ],
             },
             id="ksk-missing.autosign",
@@ -451,8 +441,8 @@ def cb_remove_keyfiles(params, ksks=None, zsks=None):
                 "config": autosign_config,
                 "offset": -timedelta(days=30 * 6),
                 "key-properties": [
-                    f"ksk 63072000 {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
-                    f"zsk 31536000 {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent missing",
+                    f"ksk 63072000 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
+                    f"zsk 31536000 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent missing",
                 ],
             },
             id="zsk-missing.autosign",
@@ -511,8 +501,8 @@ def cb_remove_keyfiles(params, ksks=None, zsks=None):
                 },
                 "key-directories": ["{keydir}/ksk", "{keydir}/zsk"],
                 "key-properties": [
-                    f"ksk unlimited {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden",
-                    f"zsk unlimited {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:rumoured zrrsig:rumoured",
+                    f"ksk unlimited {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden",
+                    f"zsk unlimited {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured zrrsig:rumoured",
                 ],
             },
             id="keystore.kasp",
@@ -613,7 +603,7 @@ def cb_remove_keyfiles(params, ksks=None, zsks=None):
                 "policy": "unlimited",
                 "config": kasp_config,
                 "key-properties": [
-                    f"csk 0 {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="unlimited.kasp",
@@ -1096,18 +1086,16 @@ def test_kasp_dynamic(ns3):
     assert f"zone_resigninc: zone {zone}/IN (unsigned): enter" not in "ns3/named.run"
 
 
-def test_kasp_checkds(ns3):
+def test_kasp_checkds(ns3, default_algorithm):
     def wait_for_metadata():
         return isctest.util.file_contents_contain(ksk.statefile, metadata)
 
     # Zone: checkds-ksk.kasp.
     zone = "checkds-ksk.kasp"
     policy = "checkds-ksk"
-    alg = os.environ["DEFAULT_ALGORITHM_NUMBER"]
-    size = os.environ["DEFAULT_BITS"]
     policy_keys = [
-        f"ksk unlimited {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden",
-        f"zsk unlimited {alg} {size} goal:omnipresent dnskey:rumoured zrrsig:rumoured",
+        f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden",
+        f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured zrrsig:rumoured",
     ]
 
     isctest.kasp.wait_keymgr_done(ns3, zone)
@@ -1140,19 +1128,17 @@ def test_kasp_checkds(ns3):
     isctest.kasp.check_keys(zone, keys, expected)
 
 
-def test_kasp_checkds_doubleksk(ns3):
+def test_kasp_checkds_doubleksk(ns3, default_algorithm):
     def wait_for_metadata():
         return isctest.util.file_contents_contain(ksk.statefile, metadata)
 
     # Zone: checkds-doubleksk.kasp.
     zone = "checkds-doubleksk.kasp"
     policy = "checkds-doubleksk"
-    alg = os.environ["DEFAULT_ALGORITHM_NUMBER"]
-    size = os.environ["DEFAULT_BITS"]
     policy_keys = [
-        f"ksk unlimited {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden",
-        f"ksk unlimited {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden",
-        f"zsk unlimited {alg} {size} goal:omnipresent dnskey:rumoured zrrsig:rumoured",
+        f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden",
+        f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden",
+        f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured zrrsig:rumoured",
     ]
 
     isctest.kasp.wait_keymgr_done(ns3, zone)
@@ -1214,17 +1200,15 @@ def test_kasp_checkds_doubleksk(ns3):
     isctest.kasp.check_keys(zone, keys, expected)
 
 
-def test_kasp_checkds_csk(ns3):
+def test_kasp_checkds_csk(ns3, default_algorithm):
     def wait_for_metadata():
         return isctest.util.file_contents_contain(ksk.statefile, metadata)
 
     # Zone: checkds-csk.kasp.
     zone = "checkds-csk.kasp"
     policy = "checkds-csk"
-    alg = os.environ["DEFAULT_ALGORITHM_NUMBER"]
-    size = os.environ["DEFAULT_BITS"]
     policy_keys = [
-        f"csk unlimited {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+        f"csk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
     ]
 
     isctest.kasp.wait_keymgr_done(ns3, zone)
@@ -1461,7 +1445,7 @@ def test_kasp_dnssec_keygen():
     isctest.kasp.check_keytimes(keys, expected)
 
 
-def test_kasp_zsk_retired(ns3):
+def test_kasp_zsk_retired(ns3, default_algorithm):
     config = {
         "dnskey-ttl": timedelta(seconds=300),
         "ds-ttl": timedelta(days=1),
@@ -1476,14 +1460,12 @@ def test_kasp_zsk_retired(ns3):
 
     zone = "zsk-retired.autosign"
     policy = "autosign"
-    alg = os.environ["DEFAULT_ALGORITHM_NUMBER"]
-    size = os.environ["DEFAULT_BITS"]
     key_properties = [
-        f"ksk 63072000 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
+        f"ksk 63072000 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
         # zsk predecessor
-        f"zsk 31536000 {alg} {size} goal:hidden dnskey:omnipresent zrrsig:omnipresent",
+        f"zsk 31536000 {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent zrrsig:omnipresent",
         # zsk successor
-        f"zsk 31536000 {alg} {size} goal:omnipresent dnskey:rumoured zrrsig:hidden",
+        f"zsk 31536000 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured zrrsig:hidden",
     ]
 
     isctest.kasp.wait_keymgr_done(ns3, zone)
@@ -1682,18 +1664,16 @@ def test_kasp_reload_restart(ns6):
     isctest.run.retry_with_timeout(check_soa_ttl, timeout=10)
 
 
-def test_kasp_manual_mode(ns3):
+def test_kasp_manual_mode(ns3, default_algorithm):
 
     keydir = ns3.identifier
     zone = "keyfiles-missing.manual"
     policy = "manual"
     ttl = int(autosign_config["dnskey-ttl"].total_seconds())
     offset = -timedelta(days=30 * 6)
-    alg = os.environ["DEFAULT_ALGORITHM_NUMBER"]
-    size = os.environ["DEFAULT_BITS"]
     keyprops = [
-        f"ksk {lifetime['P2Y']} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
-        f"zsk {lifetime['P2M']} {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
+        f"ksk {lifetime['P2Y']} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
+        f"zsk {lifetime['P2M']} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
     ]
 
     isctest.kasp.wait_keymgr_done(ns3, zone)
@@ -1768,9 +1748,9 @@ def test_kasp_manual_mode(ns3):
 
     # Check keys again, make sure the rollover has started.
     keyprops = [
-        f"ksk {lifetime['P2Y']} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
-        f"zsk {lifetime['P2M']} {alg} {size} goal:hidden dnskey:omnipresent zrrsig:omnipresent",
-        f"zsk {lifetime['P2M']} {alg} {size} goal:omnipresent dnskey:rumoured zrrsig:hidden",
+        f"ksk {lifetime['P2Y']} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
+        f"zsk {lifetime['P2M']} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent zrrsig:omnipresent",
+        f"zsk {lifetime['P2M']} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured zrrsig:hidden",
     ]
     expected = isctest.kasp.policy_to_properties(ttl=ttl, keys=keyprops)
     keys = isctest.kasp.keydir_to_keylist(zone, keydir)
diff --git a/bin/tests/system/ksr/tests_ksr.py b/bin/tests/system/ksr/tests_ksr.py
index 2164894042d..6b2cb21b651 100644
--- a/bin/tests/system/ksr/tests_ksr.py
+++ b/bin/tests/system/ksr/tests_ksr.py
@@ -19,6 +19,7 @@ import time
 import pytest
 
 from isctest.kasp import KeyTimingMetadata
+from isctest.vars.algorithms import Algorithm
 
 import isctest
 
@@ -112,12 +113,17 @@ def ksr(zone, policy, action, options="", raise_on_exception=True, to_file=""):
 def check_keys(
     keys,
     lifetime,
-    alg=os.environ["DEFAULT_ALGORITHM_DST_NUMBER"],
-    size=os.environ["DEFAULT_BITS"],
+    alg=None,
+    size=None,
     offset=0,
     with_state=False,
 ):
     # Check keys that were created.
+    if alg is None:
+        alg = Algorithm.default().dst
+    if size is None:
+        size = Algorithm.default().bits
+
     num = 0
 
     now = KeyTimingMetadata.now()
diff --git a/bin/tests/system/migrate2kasp/tests_migrate2kasp.py b/bin/tests/system/migrate2kasp/tests_migrate2kasp.py
index 76c670fafbb..26f1e34ade4 100644
--- a/bin/tests/system/migrate2kasp/tests_migrate2kasp.py
+++ b/bin/tests/system/migrate2kasp/tests_migrate2kasp.py
@@ -15,6 +15,8 @@ import os
 
 import pytest
 
+from isctest.vars.algorithms import Algorithm
+
 import isctest
 import isctest.mark
 
@@ -134,8 +136,8 @@ lifetime = {
                 "config": standard_config,
                 "offset": 0,
                 "key-properties": [
-                    f"ksk 0 {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:rumoured",
-                    f"zsk {lifetime['P60D']} {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:rumoured zrrsig:rumoured",
+                    f"ksk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:rumoured",
+                    f"zsk {lifetime['P60D']} {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured zrrsig:rumoured",
                 ],
             },
             id="migrate.kasp",
@@ -149,7 +151,7 @@ lifetime = {
                 "config": default_config,
                 "offset": 0,
                 "key-properties": [
-                    f"csk 0 {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:rumoured",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:rumoured",
                 ],
             },
             id="csk.kasp",
@@ -163,7 +165,7 @@ lifetime = {
                 "config": default_config,
                 "offset": 0,
                 "key-properties": [
-                    f"csk 0 {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:rumoured",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:rumoured",
                 ],
             },
             id="csk-nosep.kasp",
@@ -177,8 +179,8 @@ lifetime = {
                 "config": timing_config,
                 "offset": -timedelta(seconds=300),
                 "key-properties": [
-                    f"ksk {lifetime['P60D']} {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:rumoured",
-                    f"zsk {lifetime['P60D']} {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:rumoured zrrsig:rumoured",
+                    f"ksk {lifetime['P60D']} {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:rumoured",
+                    f"zsk {lifetime['P60D']} {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured zrrsig:rumoured",
                 ],
             },
             id="rumoured.kasp",
@@ -192,8 +194,8 @@ lifetime = {
                 "config": timing_config,
                 "offset": -timedelta(seconds=3900),
                 "key-properties": [
-                    f"ksk {lifetime['P60D']} {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
-                    f"zsk {lifetime['P60D']} {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
+                    f"ksk {lifetime['P60D']} {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
+                    f"zsk {lifetime['P60D']} {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
                 ],
             },
             id="omnipresent.kasp",
@@ -207,8 +209,8 @@ lifetime = {
                 "config": timing_config,
                 "offset": -timedelta(hours=12),
                 "key-properties": [
-                    f"ksk {lifetime['P60D']} {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:rumoured",
-                    f"zsk {lifetime['P60D']} {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
+                    f"ksk {lifetime['P60D']} {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:rumoured",
+                    f"zsk {lifetime['P60D']} {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
                 ],
             },
             id="no-syncpublish.kasp",
@@ -224,8 +226,8 @@ lifetime = {
                 "key-properties": [
                     "ksk - 8 2048 goal:hidden dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
                     "zsk - 8 2048 goal:hidden dnskey:omnipresent zrrsig:omnipresent",
-                    f"ksk 0 {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden",
-                    f"zsk {lifetime['P60D']} {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:rumoured zrrsig:rumoured",
+                    f"ksk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden",
+                    f"zsk {lifetime['P60D']} {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured zrrsig:rumoured",
                 ],
             },
             id="migrate-nomatch-algnum.kasp",
@@ -257,10 +259,10 @@ lifetime = {
                 "config": migrate_config,
                 "offset": -timedelta(seconds=3900),
                 "key-properties": [
-                    f"ksk - {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
-                    f"zsk - {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:hidden dnskey:omnipresent zrrsig:omnipresent",
+                    f"ksk - {Algorithm.default().number} {Algorithm.default().bits} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
+                    f"zsk - {Algorithm.default().number} {Algorithm.default().bits} goal:hidden dnskey:omnipresent zrrsig:omnipresent",
                     # This key is considered to be prepublished, so it is not yet signing, nor is the DS introduced.
-                    f"csk 0 {os.environ['DEFAULT_ALGORITHM_NUMBER']} {os.environ['DEFAULT_BITS']} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:hidden ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:hidden ds:hidden",
                 ],
             },
             id="migrate-nomatch-kzc.kasp",
diff --git a/bin/tests/system/multisigner/tests_multisigner.py b/bin/tests/system/multisigner/tests_multisigner.py
index 894c0dd5b51..1ea3ddd6d81 100644
--- a/bin/tests/system/multisigner/tests_multisigner.py
+++ b/bin/tests/system/multisigner/tests_multisigner.py
@@ -49,8 +49,6 @@ pytestmark = pytest.mark.extra_artifacts(
     ]
 )
 
-ALGORITHM = os.environ["DEFAULT_ALGORITHM_NUMBER"]
-SIZE = os.environ["DEFAULT_BITS"]
 CONFIG = {
     "dnskey-ttl": timedelta(hours=1),
     "ds-ttl": timedelta(days=1),
@@ -506,11 +504,11 @@ def check_remove_cds(
     check_dnssec(server, zone, keys, expected)
 
 
-def test_multisigner(ns2, ns3, ns4):
+def test_multisigner(ns2, ns3, ns4, default_algorithm):
     zone = "model2.multisigner"
     keyprops = [
-        f"ksk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
-        f"zsk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
+        f"ksk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
+        f"zsk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
     ]
 
     # First make sure the zone is properly signed.
@@ -550,7 +548,7 @@ def test_multisigner(ns2, ns3, ns4):
     check_dnssec(ns4, zone, keys4, expected4)
 
     # Add DNSKEY to RRset.
-    newprops = [f"zsk unlimited {ALGORITHM} {SIZE}"]
+    newprops = [f"zsk unlimited {default_algorithm.number} {default_algorithm.bits}"]
     extra = isctest.kasp.policy_to_properties(ttl=TTL, keys=newprops)
     extra[0].private = False
     extra[0].legacy = True
@@ -565,7 +563,7 @@ def test_multisigner(ns2, ns3, ns4):
     check_no_dnssec_in_journal(ns4, zone)
 
     # Add CDNSKEY RRset.
-    newprops = [f"ksk unlimited {ALGORITHM} {SIZE}"]
+    newprops = [f"ksk unlimited {default_algorithm.number} {default_algorithm.bits}"]
     extra = isctest.kasp.policy_to_properties(ttl=TTL, keys=newprops)
     extra[0].private = False
     extra[0].legacy = True
@@ -613,11 +611,11 @@ def test_multisigner_bad_dsync(ns3, ns4):
         )
 
 
-def test_multisigner_secondary(ns2, ns3, ns4, ns5):
+def test_multisigner_secondary(ns2, ns3, ns4, ns5, default_algorithm):
     zone = "model2.secondary"
     keyprops = [
-        f"ksk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
-        f"zsk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
+        f"ksk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
+        f"zsk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
     ]
 
     # First make sure the zone is properly signed.
@@ -658,7 +656,7 @@ def test_multisigner_secondary(ns2, ns3, ns4, ns5):
     check_dnssec(ns4, zone, keys4, expected4)
 
     # Add DNSKEY to RRset.
-    newprops = [f"zsk unlimited {ALGORITHM} {SIZE}"]
+    newprops = [f"zsk unlimited {default_algorithm.number} {default_algorithm.bits}"]
     extra = isctest.kasp.policy_to_properties(ttl=TTL, keys=newprops)
     extra[0].private = False
     extra[0].legacy = True
@@ -675,7 +673,7 @@ def test_multisigner_secondary(ns2, ns3, ns4, ns5):
     check_no_dnssec_in_journal(ns4, zone)
 
     # Add CDNSKEY RRset.
-    newprops = [f"ksk unlimited {ALGORITHM} {SIZE}"]
+    newprops = [f"ksk unlimited {default_algorithm.number} {default_algorithm.bits}"]
     extra = isctest.kasp.policy_to_properties(ttl=TTL, keys=newprops)
     extra[0].private = False
     extra[0].legacy = True
diff --git a/bin/tests/system/nsec3/common.py b/bin/tests/system/nsec3/common.py
index 85afe2b23a3..31c7ecd66a2 100644
--- a/bin/tests/system/nsec3/common.py
+++ b/bin/tests/system/nsec3/common.py
@@ -11,8 +11,6 @@
 
 from datetime import timedelta
 
-import os
-
 import dns
 import pytest
 
@@ -39,9 +37,6 @@ pytestmark = pytest.mark.extra_artifacts(
     ]
 )
 
-ALGORITHM = os.environ["DEFAULT_ALGORITHM_NUMBER"]
-SIZE = os.environ["DEFAULT_BITS"]
-
 default_config = {
     "dnskey-ttl": timedelta(hours=1),
     "ds-ttl": timedelta(days=1),
diff --git a/bin/tests/system/nsec3/tests_nsec3_change.py b/bin/tests/system/nsec3/tests_nsec3_change.py
index beaea9554d6..4d01eb70d05 100644
--- a/bin/tests/system/nsec3/tests_nsec3_change.py
+++ b/bin/tests/system/nsec3/tests_nsec3_change.py
@@ -19,8 +19,8 @@ import dns
 import dns.update
 import pytest
 
-from isctest.vars.algorithms import RSASHA1
-from nsec3.common import ALGORITHM, SIZE, check_nsec3_case, default_config, pytestmark
+from isctest.vars.algorithms import RSASHA1, Algorithm
+from nsec3.common import check_nsec3_case, default_config, pytestmark
 
 import isctest
 import isctest.mark
@@ -95,7 +95,7 @@ def test_nsec3_case(ns3):
             "salt-length": 8,
         },
         "key-properties": [
-            f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+            f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
         ],
     }
     zone = params["zone"]
diff --git a/bin/tests/system/nsec3/tests_nsec3_initial.py b/bin/tests/system/nsec3/tests_nsec3_initial.py
index 19ba62600d8..8148a16fd3f 100644
--- a/bin/tests/system/nsec3/tests_nsec3_initial.py
+++ b/bin/tests/system/nsec3/tests_nsec3_initial.py
@@ -17,8 +17,8 @@ import dns
 import dns.update
 import pytest
 
-from isctest.vars.algorithms import RSASHA1
-from nsec3.common import ALGORITHM, SIZE, check_nsec3_case, default_config, pytestmark
+from isctest.vars.algorithms import RSASHA1, Algorithm
+from nsec3.common import check_nsec3_case, default_config, pytestmark
 
 import isctest
 import isctest.mark
@@ -65,7 +65,7 @@ def bootstrap():
                 "zone": "nsec-to-nsec3.kasp",
                 "policy": "nsec",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec-to-nsec3.kasp",
@@ -99,10 +99,10 @@ def bootstrap():
                 "zone": "nsec3-xfr-inline.kasp",
                 "policy": "nsec",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
                 "external-keys": [
-                    f"csk 0 {ALGORITHM} {SIZE}",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits}",
                 ],
                 "external-keydir": "ns2",
             },
@@ -113,7 +113,7 @@ def bootstrap():
                 "zone": "nsec3-dynamic-update-inline.kasp",
                 "policy": "nsec",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-dynamic-update-inline.kasp",
@@ -156,7 +156,7 @@ def test_nsec_case(ns3, params):
                 "zone": "nsec3-to-rsasha1.kasp",
                 "policy": "nsec3",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent",
                 ],
             },
             id="nsec3-to-rsasha1.kasp",
@@ -167,7 +167,7 @@ def test_nsec_case(ns3, params):
                 "zone": "nsec3-to-rsasha1-ds.kasp",
                 "policy": "nsec3",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent",
                 ],
             },
             id="nsec3-to-rsasha1-ds.kasp",
@@ -178,7 +178,7 @@ def test_nsec_case(ns3, params):
                 "zone": "nsec3.kasp",
                 "policy": "nsec3",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3.kasp",
@@ -188,7 +188,7 @@ def test_nsec_case(ns3, params):
                 "zone": "nsec3-dynamic.kasp",
                 "policy": "nsec3",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-dynamic.kasp",
@@ -198,7 +198,7 @@ def test_nsec_case(ns3, params):
                 "zone": "nsec3-change.kasp",
                 "policy": "nsec3",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-change.kasp",
@@ -208,7 +208,7 @@ def test_nsec_case(ns3, params):
                 "zone": "nsec3-dynamic-change.kasp",
                 "policy": "nsec3",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-dynamic-change.kasp",
@@ -218,7 +218,7 @@ def test_nsec_case(ns3, params):
                 "zone": "nsec3-dynamic-to-inline.kasp",
                 "policy": "nsec3",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-dynamic-to-inline.kasp",
@@ -228,7 +228,7 @@ def test_nsec_case(ns3, params):
                 "zone": "nsec3-inline-to-dynamic.kasp",
                 "policy": "nsec3",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-inline-to-dynamic.kasp",
@@ -238,7 +238,7 @@ def test_nsec_case(ns3, params):
                 "zone": "nsec3-to-nsec.kasp",
                 "policy": "nsec3",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-to-nsec.kasp",
@@ -248,7 +248,7 @@ def test_nsec_case(ns3, params):
                 "zone": "nsec3-to-optout.kasp",
                 "policy": "nsec3",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-to-optout.kasp",
@@ -262,7 +262,7 @@ def test_nsec_case(ns3, params):
                     "salt-length": 0,
                 },
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-from-optout.kasp",
@@ -276,7 +276,7 @@ def test_nsec_case(ns3, params):
                     "salt-length": 8,
                 },
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-other.kasp",
diff --git a/bin/tests/system/nsec3/tests_nsec3_reconfig.py b/bin/tests/system/nsec3/tests_nsec3_reconfig.py
index a725039ed46..6c8c16b29cd 100644
--- a/bin/tests/system/nsec3/tests_nsec3_reconfig.py
+++ b/bin/tests/system/nsec3/tests_nsec3_reconfig.py
@@ -19,8 +19,8 @@ import dns
 import dns.update
 import pytest
 
-from isctest.vars.algorithms import RSASHA1
-from nsec3.common import ALGORITHM, SIZE, check_nsec3_case, default_config, pytestmark
+from isctest.vars.algorithms import RSASHA1, Algorithm
+from nsec3.common import check_nsec3_case, default_config, pytestmark
 
 import isctest
 import isctest.mark
@@ -92,7 +92,7 @@ def after_servers_start(ns3, templates):
                 "policy": "nsec3",
                 "key-properties": [
                     f"csk 0 {RSASHA1.number} 2048 goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent",
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="rsasha1-to-nsec3.kasp",
@@ -104,7 +104,7 @@ def after_servers_start(ns3, templates):
                 "policy": "nsec3",
                 "key-properties": [
                     f"csk 0 {RSASHA1.number} 2048 goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent",
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="rsasha1-to-nsec3-wait.kasp",
@@ -115,7 +115,7 @@ def after_servers_start(ns3, templates):
                 "zone": "nsec3-to-rsasha1.kasp",
                 "policy": "rsasha1",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent",
                     f"csk 0 {RSASHA1.number} 2048 goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
@@ -127,7 +127,7 @@ def after_servers_start(ns3, templates):
                 "zone": "nsec3-to-rsasha1-ds.kasp",
                 "policy": "rsasha1",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent",
                     f"csk 0 {RSASHA1.number} 2048 goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
@@ -139,7 +139,7 @@ def after_servers_start(ns3, templates):
                 "zone": "nsec3-to-nsec.kasp",
                 "policy": "nsec",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-to-nsec.kasp",
@@ -164,7 +164,7 @@ def test_nsec_case(ns3, params):
                 "zone": "nsec-to-nsec3.kasp",
                 "policy": "nsec3",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec-to-nsec3.kasp",
@@ -174,7 +174,7 @@ def test_nsec_case(ns3, params):
                 "zone": "nsec3.kasp",
                 "policy": "nsec3",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3.kasp",
@@ -184,7 +184,7 @@ def test_nsec_case(ns3, params):
                 "zone": "nsec3-dynamic.kasp",
                 "policy": "nsec3",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-dynamic.kasp",
@@ -198,7 +198,7 @@ def test_nsec_case(ns3, params):
                     "salt-length": 8,
                 },
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-dynamic-change.kasp",
@@ -208,7 +208,7 @@ def test_nsec_case(ns3, params):
                 "zone": "nsec3-dynamic-to-inline.kasp",
                 "policy": "nsec3",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-dynamic-to-inline.kasp",
@@ -218,7 +218,7 @@ def test_nsec_case(ns3, params):
                 "zone": "nsec3-inline-to-dynamic.kasp",
                 "policy": "nsec3",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-inline-to-dynamic.kasp",
@@ -235,7 +235,7 @@ def test_nsec_case(ns3, params):
         #            "salt-length": 0,
         #        },
         #        "key-properties": [
-        #            f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+        #            f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
         #        ],
         #    },
         #    id="nsec3-to-optout.kasp",
@@ -248,7 +248,7 @@ def test_nsec_case(ns3, params):
         #        "zone": "nsec3-from-optout.kasp",
         #        "policy": "optout",
         #        "key-properties": [
-        #            f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+        #            f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
         #        ],
         #    },
         #    id="nsec3-from-optout.kasp",
@@ -262,7 +262,7 @@ def test_nsec_case(ns3, params):
                     "salt-length": 8,
                 },
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-other.kasp",
@@ -286,7 +286,7 @@ def test_nsec3_ent(ns3, templates):
         "zone": "nsec3-ent.kasp",
         "policy": "nsec3",
         "key-properties": [
-            f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+            f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
         ],
     }
 
diff --git a/bin/tests/system/nsec3/tests_nsec3_reload.py b/bin/tests/system/nsec3/tests_nsec3_reload.py
index d23d7df64b6..f1d1f996659 100644
--- a/bin/tests/system/nsec3/tests_nsec3_reload.py
+++ b/bin/tests/system/nsec3/tests_nsec3_reload.py
@@ -18,7 +18,7 @@ import time
 import dns
 import pytest
 
-from nsec3.common import ALGORITHM, SIZE, check_nsec3_case
+from nsec3.common import check_nsec3_case
 
 import isctest
 
@@ -34,13 +34,13 @@ def bootstrap():
     }
 
 
-def test_nsec3_case(ns3):
+def test_nsec3_case(ns3, default_algorithm):
     # Get test parameters.
     params = {
         "zone": "nsec3-fails-to-load.kasp",
         "policy": "nsec3",
         "key-properties": [
-            f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+            f"csk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
         ],
     }
     zone = params["zone"]
diff --git a/bin/tests/system/nsec3/tests_nsec3_restart.py b/bin/tests/system/nsec3/tests_nsec3_restart.py
index 63c65381723..e74ea64780f 100644
--- a/bin/tests/system/nsec3/tests_nsec3_restart.py
+++ b/bin/tests/system/nsec3/tests_nsec3_restart.py
@@ -17,14 +17,8 @@ import dns
 import dns.update
 import pytest
 
-from nsec3.common import (
-    ALGORITHM,
-    SIZE,
-    check_nsec3_case,
-    check_nsec3param,
-    default_config,
-    pytestmark,
-)
+from isctest.vars.algorithms import Algorithm
+from nsec3.common import check_nsec3_case, check_nsec3param, default_config, pytestmark
 
 import isctest
 import isctest.mark
@@ -75,7 +69,7 @@ def perform_nsec3_tests(server, params):
                 "zone": "nsec3.kasp",
                 "policy": "nsec3",
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3.kasp",
@@ -89,7 +83,7 @@ def perform_nsec3_tests(server, params):
                     "salt-length": 8,
                 },
                 "key-properties": [
-                    f"csk 0 {ALGORITHM} {SIZE} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+                    f"csk 0 {Algorithm.default().number} {Algorithm.default().bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
                 ],
             },
             id="nsec3-other.kasp",
diff --git a/bin/tests/system/rollover-algo-csk/tests_rollover_algo_csk_reconfig.py b/bin/tests/system/rollover-algo-csk/tests_rollover_algo_csk_reconfig.py
index c2d47824ade..8bfd4a3083f 100644
--- a/bin/tests/system/rollover-algo-csk/tests_rollover_algo_csk_reconfig.py
+++ b/bin/tests/system/rollover-algo-csk/tests_rollover_algo_csk_reconfig.py
@@ -27,9 +27,7 @@ from rollover.common import (
     CDSS,
     DURATION,
     TIMEDELTA,
-    alg,
     pytestmark,
-    size,
 )
 from rollover.setup import configure_algo_csk, configure_root, configure_tld
 
@@ -87,7 +85,7 @@ def after_servers_start(ns3, templates):
         param("manual"),
     ],
 )
-def test_algoroll_csk_reconfig_step1(tld, ns3, alg, size):
+def test_algoroll_csk_reconfig_step1(tld, ns3, default_algorithm):
     zone = f"step1.csk-algorithm-roll.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -128,7 +126,7 @@ def test_algoroll_csk_reconfig_step1(tld, ns3, alg, size):
             # The RSASHA keys are outroducing.
             f"csk 0 8 2048 goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFVAL}",
             # The ECDSAP256SHA256 keys are introducing.
-            f"csk 0 {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+            f"csk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
         ],
         # Next key event is when the ecdsa256 keys have been propagated.
         "nextev": ALGOROLL_IPUB,
@@ -145,7 +143,7 @@ def test_algoroll_csk_reconfig_step1(tld, ns3, alg, size):
         param("manual"),
     ],
 )
-def test_algoroll_csk_reconfig_step2(tld, ns3, alg, size):
+def test_algoroll_csk_reconfig_step2(tld, ns3, default_algorithm):
     zone = f"step2.csk-algorithm-roll.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -163,7 +161,7 @@ def test_algoroll_csk_reconfig_step2(tld, ns3, alg, size):
             f"csk 0 8 2048 goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFVAL}",
             # The ECDSAP256SHA256 keys are introducing. The DNSKEY RRset is
             # omnipresent, but the zone signatures are not.
-            f"csk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:rumoured ds:hidden offset:{ALGOROLL_OFFSETS['step2']}",
+            f"csk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:rumoured ds:hidden offset:{ALGOROLL_OFFSETS['step2']}",
         ],
         # Next key event is when all zone signatures are signed with the
         # new algorithm.  This is the child publication interval, minus
@@ -184,7 +182,7 @@ def test_algoroll_csk_reconfig_step2(tld, ns3, alg, size):
         param("manual"),
     ],
 )
-def test_algoroll_csk_reconfig_step3(tld, ns3, alg, size):
+def test_algoroll_csk_reconfig_step3(tld, ns3, default_algorithm):
     zone = f"step3.csk-algorithm-roll.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -197,7 +195,7 @@ def test_algoroll_csk_reconfig_step3(tld, ns3, alg, size):
             "cdss": CDSS,
             "keyprops": [
                 f"csk 0 8 2048 goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFVAL}",
-                f"csk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:hidden offset:{ALGOROLL_OFFSETS['step3']}",
+                f"csk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:hidden offset:{ALGOROLL_OFFSETS['step3']}",
             ],
             "manual-mode": True,
             "nextev": None,
@@ -237,7 +235,7 @@ def test_algoroll_csk_reconfig_step3(tld, ns3, alg, size):
         "keyprops": [
             # The DS can be swapped.
             f"csk 0 8 2048 goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:unretentive offset:{ALGOROLL_OFFVAL}",
-            f"csk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:rumoured offset:{ALGOROLL_OFFSETS['step3']}",
+            f"csk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:rumoured offset:{ALGOROLL_OFFSETS['step3']}",
         ],
         # Next key event is when the DS becomes OMNIPRESENT. This happens
         # after the publication interval of the parent side.
@@ -258,7 +256,7 @@ def test_algoroll_csk_reconfig_step3(tld, ns3, alg, size):
         param("manual"),
     ],
 )
-def test_algoroll_csk_reconfig_step4(tld, ns3, alg, size):
+def test_algoroll_csk_reconfig_step4(tld, ns3, default_algorithm):
     zone = f"step4.csk-algorithm-roll.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -271,7 +269,7 @@ def test_algoroll_csk_reconfig_step4(tld, ns3, alg, size):
             "cdss": CDSS,
             "keyprops": [
                 f"csk 0 8 2048 goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:hidden offset:{ALGOROLL_OFFVAL}",
-                f"csk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFSETS['step4']}",
+                f"csk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFSETS['step4']}",
             ],
             "manual-mode": True,
             "nextev": None,
@@ -297,7 +295,7 @@ def test_algoroll_csk_reconfig_step4(tld, ns3, alg, size):
         "keyprops": [
             # The old DS is HIDDEN, we can remove the old algorithm records.
             f"csk 0 8 2048 goal:hidden dnskey:unretentive krrsig:unretentive zrrsig:unretentive ds:hidden offset:{ALGOROLL_OFFVAL}",
-            f"csk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFSETS['step4']}",
+            f"csk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFSETS['step4']}",
         ],
         # Next key event is when the old DNSKEY becomes HIDDEN.
         # This happens after the DNSKEY TTL plus zone propagation delay.
@@ -315,7 +313,7 @@ def test_algoroll_csk_reconfig_step4(tld, ns3, alg, size):
         param("manual"),
     ],
 )
-def test_algoroll_csk_reconfig_step5(tld, ns3, alg, size):
+def test_algoroll_csk_reconfig_step5(tld, ns3, default_algorithm):
     zone = f"step5.csk-algorithm-roll.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -329,7 +327,7 @@ def test_algoroll_csk_reconfig_step5(tld, ns3, alg, size):
         "keyprops": [
             # The DNSKEY becomes HIDDEN.
             f"csk 0 8 2048 goal:hidden dnskey:hidden krrsig:hidden zrrsig:unretentive ds:hidden offset:{ALGOROLL_OFFVAL}",
-            f"csk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFSETS['step5']}",
+            f"csk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFSETS['step5']}",
         ],
         # Next key event is when the RSASHA signatures become HIDDEN.
         # This happens after the max-zone-ttl plus zone propagation delay
@@ -351,7 +349,7 @@ def test_algoroll_csk_reconfig_step5(tld, ns3, alg, size):
         param("manual"),
     ],
 )
-def test_algoroll_csk_reconfig_step6(tld, ns3, alg, size):
+def test_algoroll_csk_reconfig_step6(tld, ns3, default_algorithm):
     zone = f"step6.csk-algorithm-roll.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -365,7 +363,7 @@ def test_algoroll_csk_reconfig_step6(tld, ns3, alg, size):
         "keyprops": [
             # The zone signatures are now HIDDEN.
             f"csk 0 8 2048 goal:hidden dnskey:hidden krrsig:hidden zrrsig:hidden ds:hidden offset:{ALGOROLL_OFFVAL}",
-            f"csk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFSETS['step6']}",
+            f"csk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFSETS['step6']}",
         ],
         # Next key event is never since we established the policy and the
         # keys have an unlimited lifetime.  Fallback to the default
diff --git a/bin/tests/system/rollover-algo-ksk-zsk/tests_rollover_algo_ksk_zsk_reconfig.py b/bin/tests/system/rollover-algo-ksk-zsk/tests_rollover_algo_ksk_zsk_reconfig.py
index 7d8c169e970..a9f310fccb0 100644
--- a/bin/tests/system/rollover-algo-ksk-zsk/tests_rollover_algo_ksk_zsk_reconfig.py
+++ b/bin/tests/system/rollover-algo-ksk-zsk/tests_rollover_algo_ksk_zsk_reconfig.py
@@ -27,9 +27,7 @@ from rollover.common import (
     CDSS,
     DURATION,
     TIMEDELTA,
-    alg,
     pytestmark,
-    size,
 )
 from rollover.setup import configure_algo_ksk_zsk, configure_root, configure_tld
 
@@ -85,7 +83,7 @@ def after_servers_start(ns3, templates):
         param("manual"),
     ],
 )
-def test_algoroll_ksk_zsk_reconfig_step1(tld, ns3, alg, size):
+def test_algoroll_ksk_zsk_reconfig_step1(tld, ns3, default_algorithm):
     zone = f"step1.algorithm-roll.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -130,8 +128,8 @@ def test_algoroll_ksk_zsk_reconfig_step1(tld, ns3, alg, size):
             f"ksk 0 8 2048 goal:hidden dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFVAL}",
             f"zsk 0 8 2048 goal:hidden dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFVAL}",
             # The ECDSAP256SHA256 keys are introducing.
-            f"ksk 0 {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden",
-            f"zsk 0 {alg} {size} goal:omnipresent dnskey:rumoured zrrsig:rumoured",
+            f"ksk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden",
+            f"zsk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured zrrsig:rumoured",
         ],
         # Next key event is when the ecdsa256 keys have been propagated.
         "nextev": ALGOROLL_IPUB,
@@ -148,7 +146,7 @@ def test_algoroll_ksk_zsk_reconfig_step1(tld, ns3, alg, size):
         param("manual"),
     ],
 )
-def test_algoroll_ksk_zsk_reconfig_step2(tld, ns3, alg, size):
+def test_algoroll_ksk_zsk_reconfig_step2(tld, ns3, default_algorithm):
     zone = f"step2.algorithm-roll.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -167,8 +165,8 @@ def test_algoroll_ksk_zsk_reconfig_step2(tld, ns3, alg, size):
             f"zsk 0 8 2048 goal:hidden dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFVAL}",
             # The ECDSAP256SHA256 keys are introducing. The DNSKEY RRset is
             # omnipresent, but the zone signatures are not.
-            f"ksk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:hidden offset:{ALGOROLL_OFFSETS['step2']}",
-            f"zsk 0 {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:rumoured offset:{ALGOROLL_OFFSETS['step2']}",
+            f"ksk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:hidden offset:{ALGOROLL_OFFSETS['step2']}",
+            f"zsk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:rumoured offset:{ALGOROLL_OFFSETS['step2']}",
         ],
         # Next key event is when all zone signatures are signed with the new
         # algorithm.  This is the max-zone-ttl plus zone propagation delay.  But
@@ -189,7 +187,7 @@ def test_algoroll_ksk_zsk_reconfig_step2(tld, ns3, alg, size):
         param("manual"),
     ],
 )
-def test_algoroll_ksk_zsk_reconfig_step3(tld, ns3, alg, size):
+def test_algoroll_ksk_zsk_reconfig_step3(tld, ns3, default_algorithm):
     zone = f"step3.algorithm-roll.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -203,8 +201,8 @@ def test_algoroll_ksk_zsk_reconfig_step3(tld, ns3, alg, size):
             "keyprops": [
                 f"ksk 0 8 2048 goal:hidden dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFVAL}",
                 f"zsk 0 8 2048 goal:hidden dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFVAL}",
-                f"ksk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:hidden offset:{ALGOROLL_OFFSETS['step3']}",
-                f"zsk 0 {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFSETS['step3']}",
+                f"ksk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:hidden offset:{ALGOROLL_OFFSETS['step3']}",
+                f"zsk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFSETS['step3']}",
             ],
             "manual-mode": True,
             "nextev": None,
@@ -245,8 +243,8 @@ def test_algoroll_ksk_zsk_reconfig_step3(tld, ns3, alg, size):
             # The DS can be swapped.
             f"ksk 0 8 2048 goal:hidden dnskey:omnipresent krrsig:omnipresent ds:unretentive offset:{ALGOROLL_OFFVAL}",
             f"zsk 0 8 2048 goal:hidden dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFVAL}",
-            f"ksk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:rumoured offset:{ALGOROLL_OFFSETS['step3']}",
-            f"zsk 0 {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFSETS['step3']}",
+            f"ksk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:rumoured offset:{ALGOROLL_OFFSETS['step3']}",
+            f"zsk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFSETS['step3']}",
         ],
         # Next key event is when the DS becomes OMNIPRESENT. This happens
         # after the retire interval.
@@ -267,7 +265,7 @@ def test_algoroll_ksk_zsk_reconfig_step3(tld, ns3, alg, size):
         param("manual"),
     ],
 )
-def test_algoroll_ksk_zsk_reconfig_step4(tld, ns3, alg, size):
+def test_algoroll_ksk_zsk_reconfig_step4(tld, ns3, default_algorithm):
     zone = f"step4.algorithm-roll.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -281,8 +279,8 @@ def test_algoroll_ksk_zsk_reconfig_step4(tld, ns3, alg, size):
             "keyprops": [
                 f"ksk 0 8 2048 goal:hidden dnskey:omnipresent krrsig:omnipresent ds:hidden offset:{ALGOROLL_OFFVAL}",
                 f"zsk 0 8 2048 goal:hidden dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFVAL}",
-                f"ksk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFSETS['step4']}",
-                f"zsk 0 {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFSETS['step4']}",
+                f"ksk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFSETS['step4']}",
+                f"zsk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFSETS['step4']}",
             ],
             "manual-mode": True,
             "nextev": None,
@@ -312,8 +310,8 @@ def test_algoroll_ksk_zsk_reconfig_step4(tld, ns3, alg, size):
             # The old DS is HIDDEN, we can remove the old algorithm records.
             f"ksk 0 8 2048 goal:hidden dnskey:unretentive krrsig:unretentive ds:hidden offset:{ALGOROLL_OFFVAL}",
             f"zsk 0 8 2048 goal:hidden dnskey:unretentive zrrsig:unretentive offset:{ALGOROLL_OFFVAL}",
-            f"ksk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFSETS['step4']}",
-            f"zsk 0 {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFSETS['step4']}",
+            f"ksk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFSETS['step4']}",
+            f"zsk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFSETS['step4']}",
         ],
         # Next key event is when the old DNSKEY becomes HIDDEN.
         # This happens after the DNSKEY TTL plus zone propagation delay.
@@ -331,7 +329,7 @@ def test_algoroll_ksk_zsk_reconfig_step4(tld, ns3, alg, size):
         param("manual"),
     ],
 )
-def test_algoroll_ksk_zsk_reconfig_step5(tld, ns3, alg, size):
+def test_algoroll_ksk_zsk_reconfig_step5(tld, ns3, default_algorithm):
     zone = f"step5.algorithm-roll.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -346,8 +344,8 @@ def test_algoroll_ksk_zsk_reconfig_step5(tld, ns3, alg, size):
             # The DNSKEY becomes HIDDEN.
             f"ksk 0 8 2048 goal:hidden dnskey:hidden krrsig:hidden ds:hidden offset:{ALGOROLL_OFFVAL}",
             f"zsk 0 8 2048 goal:hidden dnskey:hidden zrrsig:unretentive offset:{ALGOROLL_OFFVAL}",
-            f"ksk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFSETS['step5']}",
-            f"zsk 0 {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFSETS['step5']}",
+            f"ksk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFSETS['step5']}",
+            f"zsk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFSETS['step5']}",
         ],
         # Next key event is when the RSASHA signatures become HIDDEN.
         # This happens after the max-zone-ttl plus zone propagation delay
@@ -371,7 +369,7 @@ def test_algoroll_ksk_zsk_reconfig_step5(tld, ns3, alg, size):
         param("manual"),
     ],
 )
-def test_algoroll_ksk_zsk_reconfig_step6(tld, ns3, alg, size):
+def test_algoroll_ksk_zsk_reconfig_step6(tld, ns3, default_algorithm):
     zone = f"step6.algorithm-roll.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -386,8 +384,8 @@ def test_algoroll_ksk_zsk_reconfig_step6(tld, ns3, alg, size):
             # The zone signatures are now HIDDEN.
             f"ksk 0 8 2048 goal:hidden dnskey:hidden krrsig:hidden ds:hidden offset:{ALGOROLL_OFFVAL}",
             f"zsk 0 8 2048 goal:hidden dnskey:hidden zrrsig:hidden offset:{ALGOROLL_OFFVAL}",
-            f"ksk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFSETS['step6']}",
-            f"zsk 0 {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFSETS['step6']}",
+            f"ksk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{ALGOROLL_OFFSETS['step6']}",
+            f"zsk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{ALGOROLL_OFFSETS['step6']}",
         ],
         # Next key event is never since we established the policy and the
         # keys have an unlimited lifetime.  Fallback to the default
diff --git a/bin/tests/system/rollover-csk-roll1/tests_rollover_csk_roll1.py b/bin/tests/system/rollover-csk-roll1/tests_rollover_csk_roll1.py
index eebeea47234..ce1f94f2e5e 100644
--- a/bin/tests/system/rollover-csk-roll1/tests_rollover_csk_roll1.py
+++ b/bin/tests/system/rollover-csk-roll1/tests_rollover_csk_roll1.py
@@ -17,7 +17,7 @@ import pytest
 
 from isctest.kasp import Ipub, Iret
 from isctest.util import param
-from rollover.common import TIMEDELTA, alg, pytestmark, size
+from rollover.common import TIMEDELTA, pytestmark
 from rollover.setup import configure_cskroll1, configure_root, configure_tld
 
 import isctest
@@ -92,7 +92,7 @@ def bootstrap():
         param("manual"),
     ],
 )
-def test_csk_roll1_step1(tld, ns3, alg, size):
+def test_csk_roll1_step1(tld, ns3, default_algorithm):
     zone = f"step1.csk-roll1.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -106,7 +106,7 @@ def test_csk_roll1_step1(tld, ns3, alg, size):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step1-p']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step1-p']}",
         ],
         # Next key event is when the successor CSK needs to be published
         # minus time already elapsed. This is Lcsk - Ipub + Dreg (we ignore
@@ -125,7 +125,7 @@ def test_csk_roll1_step1(tld, ns3, alg, size):
         param("manual"),
     ],
 )
-def test_csk_roll1_step2(tld, alg, size, ns3):
+def test_csk_roll1_step2(tld, ns3, default_algorithm):
     zone = f"step2.csk-roll1.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -137,7 +137,7 @@ def test_csk_roll1_step2(tld, alg, size, ns3):
             "zone": zone,
             "cdss": CDSS,
             "keyprops": [
-                f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step2-p']}",
+                f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step2-p']}",
             ],
             "manual-mode": True,
             "nextev": None,
@@ -166,8 +166,8 @@ def test_csk_roll1_step2(tld, alg, size, ns3):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step2-p']}",
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:hidden ds:hidden offset:{OFFSETS['step2-s']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step2-p']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:hidden ds:hidden offset:{OFFSETS['step2-s']}",
         ],
         "keyrelationships": [0, 1],
         # Next key event is when the successor CSK becomes OMNIPRESENT.
@@ -185,7 +185,7 @@ def test_csk_roll1_step2(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_csk_roll1_step3(tld, alg, size, ns3):
+def test_csk_roll1_step3(tld, ns3, default_algorithm):
     zone = f"step3.csk-roll1.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -197,8 +197,8 @@ def test_csk_roll1_step3(tld, alg, size, ns3):
             "zone": zone,
             "cdss": CDSS,
             "keyprops": [
-                f"csk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step3-p']}",
-                f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:hidden ds:hidden offset:{OFFSETS['step3-s']}",
+                f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step3-p']}",
+                f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:hidden ds:hidden offset:{OFFSETS['step3-s']}",
             ],
             "keyrelationships": [0, 1],
             "manual-mode": True,
@@ -249,8 +249,8 @@ def test_csk_roll1_step3(tld, alg, size, ns3):
         # CSK1 ds: omnipresent -> unretentive
         # CSK2 ds: hidden -> rumoured
         "keyprops": [
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:unretentive ds:unretentive offset:{OFFSETS['step3-p']}",
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:rumoured ds:rumoured offset:{OFFSETS['step3-s']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:unretentive ds:unretentive offset:{OFFSETS['step3-p']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:rumoured ds:rumoured offset:{OFFSETS['step3-s']}",
         ],
         "keyrelationships": [0, 1],
         # Next key event is when the predecessor DS has been replaced with
@@ -277,7 +277,7 @@ def test_csk_roll1_step3(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_csk_roll1_step4(tld, alg, size, ns3):
+def test_csk_roll1_step4(tld, ns3, default_algorithm):
     zone = f"step4.csk-roll1.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -289,8 +289,8 @@ def test_csk_roll1_step4(tld, alg, size, ns3):
             "zone": zone,
             "cdss": CDSS,
             "keyprops": [
-                f"csk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:unretentive ds:hidden offset:{OFFSETS['step4-p']}",
-                f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:rumoured ds:omnipresent offset:{OFFSETS['step4-s']}",
+                f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:unretentive ds:hidden offset:{OFFSETS['step4-p']}",
+                f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:rumoured ds:omnipresent offset:{OFFSETS['step4-s']}",
             ],
             "keyrelationships": [0, 1],
             "manual-mode": True,
@@ -322,8 +322,8 @@ def test_csk_roll1_step4(tld, alg, size, ns3):
         # CSK1 ds: unretentive -> hidden
         # CSK2 ds: rumoured -> omnipresent
         "keyprops": [
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:unretentive zrrsig:unretentive ds:hidden offset:{OFFSETS['step4-p']}",
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:rumoured ds:omnipresent offset:{OFFSETS['step4-s']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:unretentive zrrsig:unretentive ds:hidden offset:{OFFSETS['step4-p']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:rumoured ds:omnipresent offset:{OFFSETS['step4-s']}",
         ],
         "keyrelationships": [0, 1],
         # Next key event is when the KRRSIG enters the HIDDEN state.
@@ -344,7 +344,7 @@ def test_csk_roll1_step4(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_csk_roll1_step5(tld, alg, size, ns3):
+def test_csk_roll1_step5(tld, ns3, default_algorithm):
     zone = f"step5.csk-roll1.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -358,8 +358,8 @@ def test_csk_roll1_step5(tld, alg, size, ns3):
         # The predecessor KRRSIG records are now all hidden.
         # CSK1 krrsig: unretentive -> hidden
         "keyprops": [
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:hidden zrrsig:unretentive ds:hidden offset:{OFFSETS['step5-p']}",
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:rumoured ds:omnipresent offset:{OFFSETS['step5-s']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:hidden zrrsig:unretentive ds:hidden offset:{OFFSETS['step5-p']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:rumoured ds:omnipresent offset:{OFFSETS['step5-s']}",
         ],
         "keyrelationships": [0, 1],
         # Next key event is when the DNSKEY can be removed.  This is when
@@ -379,7 +379,7 @@ def test_csk_roll1_step5(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_csk_roll1_step6(tld, alg, size, ns3):
+def test_csk_roll1_step6(tld, ns3, default_algorithm):
     zone = f"step6.csk-roll1.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -397,8 +397,8 @@ def test_csk_roll1_step6(tld, alg, size, ns3):
         # CSK1 zrrsig: unretentive -> hidden
         # CSK2 zrrsig: rumoured -> omnipresent
         "keyprops": [
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:unretentive krrsig:hidden zrrsig:hidden ds:hidden offset:{OFFSETS['step6-p']}",
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step6-s']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:unretentive krrsig:hidden zrrsig:hidden ds:hidden offset:{OFFSETS['step6-p']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step6-s']}",
         ],
         "keyrelationships": [0, 1],
         # Next key event is when the DNSKEY enters the HIDDEN state.
@@ -417,7 +417,7 @@ def test_csk_roll1_step6(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_csk_roll1_step7(tld, alg, size, ns3):
+def test_csk_roll1_step7(tld, ns3, default_algorithm):
     zone = f"step7.csk-roll1.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -430,8 +430,8 @@ def test_csk_roll1_step7(tld, alg, size, ns3):
         "cdss": CDSS,
         # The predecessor CSK is now completely HIDDEN.
         "keyprops": [
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:hidden krrsig:hidden zrrsig:hidden ds:hidden offset:{OFFSETS['step7-p']}",
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step7-s']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:hidden krrsig:hidden zrrsig:hidden ds:hidden offset:{OFFSETS['step7-p']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step7-s']}",
         ],
         "keyrelationships": [0, 1],
         # Next key event is when the new successor needs to be published.
@@ -451,7 +451,7 @@ def test_csk_roll1_step7(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_csk_roll1_step8(tld, alg, size, ns3):
+def test_csk_roll1_step8(tld, ns3, default_algorithm):
     zone = f"step8.csk-roll1.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -463,7 +463,7 @@ def test_csk_roll1_step8(tld, alg, size, ns3):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step8-s']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step8-s']}",
         ],
         "nextev": None,
     }
diff --git a/bin/tests/system/rollover-csk-roll2/tests_rollover_csk_roll2.py b/bin/tests/system/rollover-csk-roll2/tests_rollover_csk_roll2.py
index 9993b83ecdc..b63c59b35dd 100644
--- a/bin/tests/system/rollover-csk-roll2/tests_rollover_csk_roll2.py
+++ b/bin/tests/system/rollover-csk-roll2/tests_rollover_csk_roll2.py
@@ -17,7 +17,7 @@ import pytest
 
 from isctest.kasp import Ipub, Iret
 from isctest.util import param
-from rollover.common import TIMEDELTA, alg, pytestmark, size
+from rollover.common import TIMEDELTA, pytestmark
 from rollover.setup import configure_cskroll2, configure_root, configure_tld
 
 import isctest
@@ -95,7 +95,7 @@ def bootstrap():
         param("manual"),
     ],
 )
-def test_csk_roll2_step1(tld, alg, size, ns3):
+def test_csk_roll2_step1(tld, ns3, default_algorithm):
     zone = f"step1.csk-roll2.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -109,7 +109,7 @@ def test_csk_roll2_step1(tld, alg, size, ns3):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step1-p']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step1-p']}",
         ],
         # Next key event is when the successor CSK needs to be published
         # minus time already elapsed. This is Lcsk - Ipub + Dreg (we ignore
@@ -128,7 +128,7 @@ def test_csk_roll2_step1(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_csk_roll2_step2(tld, alg, size, ns3):
+def test_csk_roll2_step2(tld, ns3, default_algorithm):
     zone = f"step2.csk-roll2.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -140,7 +140,7 @@ def test_csk_roll2_step2(tld, alg, size, ns3):
             "zone": zone,
             "cdss": CDSS,
             "keyprops": [
-                f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step2-p']}",
+                f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step2-p']}",
             ],
             "manual-mode": True,
             "nextev": None,
@@ -169,8 +169,8 @@ def test_csk_roll2_step2(tld, alg, size, ns3):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step2-p']}",
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:hidden ds:hidden offset:{OFFSETS['step2-s']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step2-p']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:hidden ds:hidden offset:{OFFSETS['step2-s']}",
         ],
         "keyrelationships": [0, 1],
         # Next key event is when the successor CSK becomes OMNIPRESENT.
@@ -188,7 +188,7 @@ def test_csk_roll2_step2(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_csk_roll2_step3(tld, alg, size, ns3):
+def test_csk_roll2_step3(tld, ns3, default_algorithm):
     zone = f"step3.csk-roll2.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -200,8 +200,8 @@ def test_csk_roll2_step3(tld, alg, size, ns3):
             "zone": zone,
             "cdss": CDSS,
             "keyprops": [
-                f"csk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step3-p']}",
-                f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:hidden ds:hidden offset:{OFFSETS['step3-s']}",
+                f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step3-p']}",
+                f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:hidden ds:hidden offset:{OFFSETS['step3-s']}",
             ],
             "keyrelationships": [0, 1],
             "manual-mode": True,
@@ -252,8 +252,8 @@ def test_csk_roll2_step3(tld, alg, size, ns3):
         # CSK1 ds: omnipresent -> unretentive
         # CSK2 ds: hidden -> rumoured
         "keyprops": [
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:unretentive ds:unretentive offset:{OFFSETS['step3-p']}",
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:rumoured ds:rumoured offset:{OFFSETS['step3-s']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:unretentive ds:unretentive offset:{OFFSETS['step3-p']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:rumoured ds:rumoured offset:{OFFSETS['step3-s']}",
         ],
         "keyrelationships": [0, 1],
         # Next key event is when the predecessor DS has been replaced with
@@ -280,7 +280,7 @@ def test_csk_roll2_step3(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_csk_roll2_step4(tld, alg, size, ns3):
+def test_csk_roll2_step4(tld, ns3, default_algorithm):
     zone = f"step4.csk-roll2.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -296,8 +296,8 @@ def test_csk_roll2_step4(tld, alg, size, ns3):
         # CSK1 zrrsig: unretentive -> hidden
         # CSK2 zrrsig: rumoured -> omnipresent
         "keyprops": [
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:hidden ds:unretentive offset:{OFFSETS['step4-p']}",
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:rumoured offset:{OFFSETS['step4-s']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:hidden ds:unretentive offset:{OFFSETS['step4-p']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:rumoured offset:{OFFSETS['step4-s']}",
         ],
         "keyrelationships": [0, 1],
         # Next key event is when the predecessor DS has been replaced with
@@ -321,7 +321,7 @@ def test_csk_roll2_step4(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_csk_roll2_step5(tld, alg, size, ns3):
+def test_csk_roll2_step5(tld, ns3, default_algorithm):
     zone = f"step5.csk-roll2.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -333,8 +333,8 @@ def test_csk_roll2_step5(tld, alg, size, ns3):
             "zone": zone,
             "cdss": CDSS,
             "keyprops": [
-                f"csk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:hidden ds:hidden offset:{OFFSETS['step5-p']}",
-                f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step5-s']}",
+                f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent zrrsig:hidden ds:hidden offset:{OFFSETS['step5-p']}",
+                f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step5-s']}",
             ],
             "keyrelationships": [0, 1],
             "manual-mode": True,
@@ -367,8 +367,8 @@ def test_csk_roll2_step5(tld, alg, size, ns3):
         # The successor key is now fully OMNIPRESENT.
         # CSK2 ds: rumoured -> omnipresent
         "keyprops": [
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:unretentive krrsig:unretentive zrrsig:hidden ds:hidden offset:{OFFSETS['step5-p']}",
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step5-s']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:unretentive krrsig:unretentive zrrsig:hidden ds:hidden offset:{OFFSETS['step5-p']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step5-s']}",
         ],
         "keyrelationships": [0, 1],
         # Next key event is when the DNSKEY enters the HIDDEN state.
@@ -387,7 +387,7 @@ def test_csk_roll2_step5(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_csk_roll2_step6(tld, alg, size, ns3):
+def test_csk_roll2_step6(tld, ns3, default_algorithm):
     zone = f"step6.csk-roll2.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -402,8 +402,8 @@ def test_csk_roll2_step6(tld, alg, size, ns3):
         # CSK1 dnskey: unretentive -> hidden
         # CSK1 krrsig: unretentive -> hidden
         "keyprops": [
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:hidden krrsig:hidden zrrsig:hidden ds:hidden offset:{OFFSETS['step6-p']}",
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step6-s']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:hidden krrsig:hidden zrrsig:hidden ds:hidden offset:{OFFSETS['step6-p']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step6-s']}",
         ],
         "keyrelationships": [0, 1],
         # Next key event is when the new successor needs to be published.
@@ -424,7 +424,7 @@ def test_csk_roll2_step6(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_csk_roll2_step7(tld, alg, size, ns3):
+def test_csk_roll2_step7(tld, ns3, default_algorithm):
     zone = f"step7.csk-roll2.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -437,8 +437,8 @@ def test_csk_roll2_step7(tld, alg, size, ns3):
         "cdss": CDSS,
         # The predecessor CSK is now completely HIDDEN.
         "keyprops": [
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:hidden krrsig:hidden zrrsig:hidden ds:hidden offset:{OFFSETS['step7-p']}",
-            f"csk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step7-s']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:hidden krrsig:hidden zrrsig:hidden ds:hidden offset:{OFFSETS['step7-p']}",
+            f"csk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step7-s']}",
         ],
         "keyrelationships": [0, 1],
         "nextev": None,
diff --git a/bin/tests/system/rollover-dynamic2inline/tests_rollover_dynamic2inline.py b/bin/tests/system/rollover-dynamic2inline/tests_rollover_dynamic2inline.py
index 946a7c14201..925b0b0b1cb 100644
--- a/bin/tests/system/rollover-dynamic2inline/tests_rollover_dynamic2inline.py
+++ b/bin/tests/system/rollover-dynamic2inline/tests_rollover_dynamic2inline.py
@@ -11,12 +11,12 @@
 
 # pylint: disable=redefined-outer-name,unused-import
 
-from rollover.common import CDSS, DEFAULT_CONFIG, alg, pytestmark, size
+from rollover.common import CDSS, DEFAULT_CONFIG, pytestmark
 
 import isctest
 
 
-def test_dynamic2inline(alg, size, ns3, templates):
+def test_dynamic2inline(ns3, default_algorithm, templates):
     config = DEFAULT_CONFIG
     policy = "default"
     zone = "dynamic2inline.kasp"
@@ -27,7 +27,7 @@ def test_dynamic2inline(alg, size, ns3, templates):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"csk unlimited {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+            f"csk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
         ],
         "nextev": None,
     }
diff --git a/bin/tests/system/rollover-enable-dnssec/tests_rollover_enable_dnssec.py b/bin/tests/system/rollover-enable-dnssec/tests_rollover_enable_dnssec.py
index 30d24e403ca..c6a616b6c44 100644
--- a/bin/tests/system/rollover-enable-dnssec/tests_rollover_enable_dnssec.py
+++ b/bin/tests/system/rollover-enable-dnssec/tests_rollover_enable_dnssec.py
@@ -15,7 +15,7 @@ import pytest
 
 from isctest.kasp import Ipub, IpubC, Iret
 from isctest.util import param
-from rollover.common import CDSS, TIMEDELTA, alg, pytestmark, size
+from rollover.common import CDSS, TIMEDELTA, pytestmark
 from rollover.setup import configure_enable_dnssec, configure_root, configure_tld
 
 import isctest
@@ -74,7 +74,7 @@ def bootstrap():
         param("manual"),
     ],
 )
-def test_rollover_enable_dnssec_step1(tld, alg, size, ns3):
+def test_rollover_enable_dnssec_step1(tld, default_algorithm, ns3):
     zone = f"step1.enable-dnssec.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -105,7 +105,7 @@ def test_rollover_enable_dnssec_step1(tld, alg, size, ns3):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"csk unlimited {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden offset:{OFFSETS['step1']}",
+            f"csk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden offset:{OFFSETS['step1']}",
         ],
         # Next key event is when the DNSKEY RRset becomes OMNIPRESENT,
         # after the publication interval.
@@ -123,7 +123,7 @@ def test_rollover_enable_dnssec_step1(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_rollover_enable_dnssec_step2(tld, alg, size, ns3):
+def test_rollover_enable_dnssec_step2(tld, default_algorithm, ns3):
     zone = f"step2.enable-dnssec.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -139,7 +139,7 @@ def test_rollover_enable_dnssec_step2(tld, alg, size, ns3):
         # dnskey: rumoured -> omnipresent
         # krrsig: rumoured -> omnipresent
         "keyprops": [
-            f"csk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:rumoured ds:hidden offset:{OFFSETS['step2']}",
+            f"csk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:rumoured ds:hidden offset:{OFFSETS['step2']}",
         ],
         # Next key event is when the zone signatures become OMNIPRESENT,
         # Minus the time already elapsed.
@@ -157,7 +157,7 @@ def test_rollover_enable_dnssec_step2(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_rollover_enable_dnssec_step3(tld, alg, size, ns3):
+def test_rollover_enable_dnssec_step3(tld, default_algorithm, ns3):
     zone = f"step3.enable-dnssec.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -169,7 +169,7 @@ def test_rollover_enable_dnssec_step3(tld, alg, size, ns3):
             "zone": zone,
             "cdss": CDSS,
             "keyprops": [
-                f"csk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:hidden offset:{OFFSETS['step3']}",
+                f"csk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:hidden offset:{OFFSETS['step3']}",
             ],
             "manual-mode": True,
             "nextev": None,
@@ -195,7 +195,7 @@ def test_rollover_enable_dnssec_step3(tld, alg, size, ns3):
         # zrrsig: rumoured -> omnipresent
         # ds: hidden -> rumoured
         "keyprops": [
-            f"csk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:rumoured offset:{OFFSETS['step3']}",
+            f"csk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:rumoured offset:{OFFSETS['step3']}",
         ],
         # Next key event is when the DS can move to the OMNIPRESENT state.
         # This is after the retire interval.
@@ -216,7 +216,7 @@ def test_rollover_enable_dnssec_step3(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_rollover_enable_dnssec_step4(tld, alg, size, ns3):
+def test_rollover_enable_dnssec_step4(tld, default_algorithm, ns3):
     zone = f"step4.enable-dnssec.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -230,7 +230,7 @@ def test_rollover_enable_dnssec_step4(tld, alg, size, ns3):
         # DS has been published long enough.
         # ds: rumoured -> omnipresent
         "keyprops": [
-            f"csk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step4']}",
+            f"csk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{OFFSETS['step4']}",
         ],
         # Next key event is never, the zone dnssec-policy has been
         # established. So we fall back to the default loadkeys interval.
diff --git a/bin/tests/system/rollover-going-insecure/tests_rollover_going_insecure_initial.py b/bin/tests/system/rollover-going-insecure/tests_rollover_going_insecure_initial.py
index a521948fc23..9e697156a66 100644
--- a/bin/tests/system/rollover-going-insecure/tests_rollover_going_insecure_initial.py
+++ b/bin/tests/system/rollover-going-insecure/tests_rollover_going_insecure_initial.py
@@ -13,7 +13,7 @@
 
 import pytest
 
-from rollover.common import CDSS, DURATION, UNSIGNING_CONFIG, alg, pytestmark, size
+from rollover.common import CDSS, DURATION, UNSIGNING_CONFIG, pytestmark
 from rollover.setup import configure_going_insecure, configure_root, configure_tld
 
 import isctest
@@ -43,7 +43,7 @@ def bootstrap():
         "going-insecure-dynamic.kasp",
     ],
 )
-def test_going_insecure_initial(zone, ns3, alg, size):
+def test_going_insecure_initial(zone, ns3, default_algorithm):
     config = UNSIGNING_CONFIG
     policy = "unsigning"
     zone = f"step1.{zone}"
@@ -54,8 +54,8 @@ def test_going_insecure_initial(zone, ns3, alg, size):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"ksk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{-DURATION['P10D']}",
-            f"zsk {DURATION['P60D']} {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{-DURATION['P10D']}",
+            f"ksk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{-DURATION['P10D']}",
+            f"zsk {DURATION['P60D']} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{-DURATION['P10D']}",
         ],
         "nextev": None,
     }
diff --git a/bin/tests/system/rollover-going-insecure/tests_rollover_going_insecure_reconfig.py b/bin/tests/system/rollover-going-insecure/tests_rollover_going_insecure_reconfig.py
index 9fb23b19877..9abff654fd7 100644
--- a/bin/tests/system/rollover-going-insecure/tests_rollover_going_insecure_reconfig.py
+++ b/bin/tests/system/rollover-going-insecure/tests_rollover_going_insecure_reconfig.py
@@ -13,15 +13,7 @@
 
 import pytest
 
-from rollover.common import (
-    CDSS,
-    DEFAULT_CONFIG,
-    DURATION,
-    UNSIGNING_CONFIG,
-    alg,
-    pytestmark,
-    size,
-)
+from rollover.common import CDSS, DEFAULT_CONFIG, DURATION, UNSIGNING_CONFIG, pytestmark
 from rollover.setup import configure_going_insecure, configure_root, configure_tld
 
 import isctest
@@ -57,7 +49,7 @@ def after_servers_start(ns3, templates):
         "going-insecure-dynamic.kasp",
     ],
 )
-def test_going_insecure_reconfig_step1(zone, alg, size, ns3):
+def test_going_insecure_reconfig_step1(zone, ns3, default_algorithm):
     config = DEFAULT_CONFIG
     policy = "insecure"
     szone = f"step1.{zone}"
@@ -70,8 +62,8 @@ def test_going_insecure_reconfig_step1(zone, alg, size, ns3):
         "zone": szone,
         "cdss": CDSS,
         "keyprops": [
-            f"ksk 0 {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:unretentive offset:{-DURATION['P10D']}",
-            f"zsk {DURATION['P60D']} {alg} {size} goal:hidden dnskey:omnipresent zrrsig:omnipresent offset:{-DURATION['P10D']}",
+            f"ksk 0 {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:unretentive offset:{-DURATION['P10D']}",
+            f"zsk {DURATION['P60D']} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent zrrsig:omnipresent offset:{-DURATION['P10D']}",
         ],
         # Next key event is when the DS becomes HIDDEN. This
         # happens after the# parent propagation delay plus DS TTL.
@@ -100,7 +92,7 @@ def test_going_insecure_reconfig_step1(zone, alg, size, ns3):
         "going-insecure-dynamic.kasp",
     ],
 )
-def test_going_insecure_reconfig_step2(zone, alg, size, ns3):
+def test_going_insecure_reconfig_step2(zone, ns3, default_algorithm):
     config = DEFAULT_CONFIG
     policy = "insecure"
     zone = f"step2.{zone}"
@@ -114,8 +106,8 @@ def test_going_insecure_reconfig_step2(zone, alg, size, ns3):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"ksk 0 {alg} {size} goal:hidden dnskey:unretentive krrsig:unretentive ds:hidden offset:{-DURATION['P10D']}",
-            f"zsk {DURATION['P60D']} {alg} {size} goal:hidden dnskey:unretentive zrrsig:unretentive offset:{-DURATION['P10D']}",
+            f"ksk 0 {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:unretentive krrsig:unretentive ds:hidden offset:{-DURATION['P10D']}",
+            f"zsk {DURATION['P60D']} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:unretentive zrrsig:unretentive offset:{-DURATION['P10D']}",
         ],
         # Next key event is when the DNSKEY becomes HIDDEN.
         # This happens after the propagation delay, plus DNSKEY TTL.
diff --git a/bin/tests/system/rollover-ksk-3crowd/tests_rollover_three_is_a_crowd.py b/bin/tests/system/rollover-ksk-3crowd/tests_rollover_three_is_a_crowd.py
index 07710d19b07..a7580640911 100644
--- a/bin/tests/system/rollover-ksk-3crowd/tests_rollover_three_is_a_crowd.py
+++ b/bin/tests/system/rollover-ksk-3crowd/tests_rollover_three_is_a_crowd.py
@@ -19,9 +19,7 @@ from rollover.common import (
     KSK_IPUB,
     KSK_IRET,
     KSK_LIFETIME_POLICY,
-    alg,
     pytestmark,
-    size,
 )
 from rollover.setup import configure_ksk_3crowd, configure_root, configure_tld
 
@@ -51,7 +49,7 @@ def bootstrap():
     return data
 
 
-def test_rollover_ksk_three_is_a_crowd(alg, size, ns3):
+def test_rollover_ksk_three_is_a_crowd(ns3, default_algorithm):
     """Test #2375: Scheduled rollovers are happening faster than they can finish."""
     zone = "three-is-a-crowd.kasp"
 
@@ -61,9 +59,9 @@ def test_rollover_ksk_three_is_a_crowd(alg, size, ns3):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:unretentive offset:{OFFSET1}",
-            f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:rumoured offset:{OFFSET2}",
-            f"zsk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSET1}",
+            f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:unretentive offset:{OFFSET1}",
+            f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:rumoured offset:{OFFSET2}",
+            f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSET1}",
         ],
         "keyrelationships": [0, 1],
     }
@@ -84,10 +82,10 @@ def test_rollover_ksk_three_is_a_crowd(alg, size, ns3):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:unretentive offset:{OFFSET1}",
-            f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:rumoured offset:{OFFSET2}",
-            f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden offset:0",
-            f"zsk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSET1}",
+            f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:unretentive offset:{OFFSET1}",
+            f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:rumoured offset:{OFFSET2}",
+            f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden offset:0",
+            f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSET1}",
         ],
         "check-keytimes": False,  # checked manually with modified values
     }
diff --git a/bin/tests/system/rollover-ksk-doubleksk/tests_rollover_ksk_doubleksk.py b/bin/tests/system/rollover-ksk-doubleksk/tests_rollover_ksk_doubleksk.py
index 8eccb702d72..5c4e58c2086 100644
--- a/bin/tests/system/rollover-ksk-doubleksk/tests_rollover_ksk_doubleksk.py
+++ b/bin/tests/system/rollover-ksk-doubleksk/tests_rollover_ksk_doubleksk.py
@@ -25,9 +25,7 @@ from rollover.common import (
     KSK_LIFETIME,
     KSK_LIFETIME_POLICY,
     TIMEDELTA,
-    alg,
     pytestmark,
-    size,
 )
 from rollover.setup import configure_ksk_doubleksk, configure_root, configure_tld
 
@@ -80,7 +78,7 @@ def bootstrap():
         param("manual"),
     ],
 )
-def test_ksk_doubleksk_step1(tld, alg, size, ns3):
+def test_ksk_doubleksk_step1(tld, ns3, default_algorithm):
     zone = f"step1.ksk-doubleksk.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -94,8 +92,8 @@ def test_ksk_doubleksk_step1(tld, alg, size, ns3):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"zsk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step1-p']}",
-            f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step1-p']}",
+            f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step1-p']}",
+            f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step1-p']}",
         ],
         # Next key event is when the successor KSK needs to be published.
         # That is the KSK lifetime - prepublication time (minus time
@@ -114,7 +112,7 @@ def test_ksk_doubleksk_step1(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_ksk_doubleksk_step2(tld, alg, size, ns3):
+def test_ksk_doubleksk_step2(tld, ns3, default_algorithm):
     zone = f"step2.ksk-doubleksk.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -126,8 +124,8 @@ def test_ksk_doubleksk_step2(tld, alg, size, ns3):
             "zone": zone,
             "cdss": CDSS,
             "keyprops": [
-                f"zsk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step2-p']}",
-                f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step2-p']}",
+                f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step2-p']}",
+                f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step2-p']}",
             ],
             "manual-mode": True,
             "nextev": None,
@@ -155,9 +153,9 @@ def test_ksk_doubleksk_step2(tld, alg, size, ns3):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"zsk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step2-p']}",
-            f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step2-p']}",
-            f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden offset:{OFFSETS['step2-s']}",
+            f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step2-p']}",
+            f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step2-p']}",
+            f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden offset:{OFFSETS['step2-s']}",
         ],
         "keyrelationships": [1, 2],
         # Next key event is when the successor KSK becomes OMNIPRESENT.
@@ -175,7 +173,7 @@ def test_ksk_doubleksk_step2(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_ksk_doubleksk_step3(tld, alg, size, ns3):
+def test_ksk_doubleksk_step3(tld, ns3, default_algorithm):
     zone = f"step3.ksk-doubleksk.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -187,9 +185,9 @@ def test_ksk_doubleksk_step3(tld, alg, size, ns3):
             "zone": zone,
             "cdss": CDSS,
             "keyprops": [
-                f"zsk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step3-p']}",
-                f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step3-p']}",
-                f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:hidden offset:{OFFSETS['step3-s']}",
+                f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step3-p']}",
+                f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step3-p']}",
+                f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:hidden offset:{OFFSETS['step3-s']}",
             ],
             "keyrelationships": [1, 2],
             "manual-mode": True,
@@ -234,9 +232,9 @@ def test_ksk_doubleksk_step3(tld, alg, size, ns3):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"zsk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step3-p']}",
-            f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:unretentive offset:{OFFSETS['step3-p']}",
-            f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:rumoured offset:{OFFSETS['step3-s']}",
+            f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step3-p']}",
+            f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:unretentive offset:{OFFSETS['step3-p']}",
+            f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:rumoured offset:{OFFSETS['step3-s']}",
         ],
         "keyrelationships": [1, 2],
         # Next key event is when the predecessor DS has been replaced with
@@ -260,7 +258,7 @@ def test_ksk_doubleksk_step3(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_ksk_doubleksk_step4(tld, alg, size, ns3):
+def test_ksk_doubleksk_step4(tld, ns3, default_algorithm):
     zone = f"step4.ksk-doubleksk.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -272,9 +270,9 @@ def test_ksk_doubleksk_step4(tld, alg, size, ns3):
             "zone": zone,
             "cdss": CDSS,
             "keyprops": [
-                f"zsk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step4-p']}",
-                f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:hidden offset:{OFFSETS['step4-p']}",
-                f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step4-s']}",
+                f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step4-p']}",
+                f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:hidden offset:{OFFSETS['step4-p']}",
+                f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step4-s']}",
             ],
             "keyrelationships": [1, 2],
             "manual-mode": True,
@@ -307,9 +305,9 @@ def test_ksk_doubleksk_step4(tld, alg, size, ns3):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"zsk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step4-p']}",
-            f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:unretentive krrsig:unretentive ds:hidden offset:{OFFSETS['step4-p']}",
-            f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step4-s']}",
+            f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step4-p']}",
+            f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:unretentive krrsig:unretentive ds:hidden offset:{OFFSETS['step4-p']}",
+            f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step4-s']}",
         ],
         "keyrelationships": [1, 2],
         # Next key event is when the DNSKEY enters the HIDDEN state.
@@ -328,7 +326,7 @@ def test_ksk_doubleksk_step4(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_ksk_doubleksk_step5(tld, alg, size, ns3):
+def test_ksk_doubleksk_step5(tld, ns3, default_algorithm):
     zone = f"step5.ksk-doubleksk.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -344,9 +342,9 @@ def test_ksk_doubleksk_step5(tld, alg, size, ns3):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"zsk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step5-p']}",
-            f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:hidden krrsig:hidden ds:hidden offset:{OFFSETS['step5-p']}",
-            f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step5-s']}",
+            f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step5-p']}",
+            f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:hidden krrsig:hidden ds:hidden offset:{OFFSETS['step5-p']}",
+            f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step5-s']}",
         ],
         "keyrelationships": [1, 2],
         # Next key event is when the new successor needs to be published.
@@ -367,7 +365,7 @@ def test_ksk_doubleksk_step5(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_ksk_doubleksk_step6(tld, alg, size, ns3):
+def test_ksk_doubleksk_step6(tld, ns3, default_algorithm):
     zone = f"step6.ksk-doubleksk.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -380,8 +378,8 @@ def test_ksk_doubleksk_step6(tld, alg, size, ns3):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"zsk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step6-p']}",
-            f"ksk {KSK_LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step6-s']}",
+            f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step6-p']}",
+            f"ksk {KSK_LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step6-s']}",
         ],
         "nextev": None,
     }
diff --git a/bin/tests/system/rollover-lifetime/tests_rollover_lifetime_initial.py b/bin/tests/system/rollover-lifetime/tests_rollover_lifetime_initial.py
index a770814f8ad..f37cb3690f0 100644
--- a/bin/tests/system/rollover-lifetime/tests_rollover_lifetime_initial.py
+++ b/bin/tests/system/rollover-lifetime/tests_rollover_lifetime_initial.py
@@ -14,7 +14,7 @@
 import pytest
 
 from isctest.util import param
-from rollover.common import CDSS, DEFAULT_CONFIG, DURATION, alg, pytestmark, size
+from rollover.common import CDSS, DEFAULT_CONFIG, DURATION, pytestmark
 
 import isctest
 
@@ -28,7 +28,7 @@ import isctest
         param("unlimit-lifetime", "short-lifetime", "P6M"),
     ],
 )
-def test_lifetime_initial(zone, policy, lifetime, alg, size, ns3):
+def test_lifetime_initial(zone, policy, lifetime, ns3, default_algorithm):
     config = DEFAULT_CONFIG
 
     isctest.kasp.wait_keymgr_done(ns3, f"{zone}.kasp")
@@ -37,7 +37,7 @@ def test_lifetime_initial(zone, policy, lifetime, alg, size, ns3):
         "zone": f"{zone}.kasp",
         "cdss": CDSS,
         "keyprops": [
-            f"csk {DURATION[lifetime]} {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+            f"csk {DURATION[lifetime]} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
         ],
         "nextev": None,
     }
diff --git a/bin/tests/system/rollover-lifetime/tests_rollover_lifetime_reconfig.py b/bin/tests/system/rollover-lifetime/tests_rollover_lifetime_reconfig.py
index ff697a05293..345bd2bc65a 100644
--- a/bin/tests/system/rollover-lifetime/tests_rollover_lifetime_reconfig.py
+++ b/bin/tests/system/rollover-lifetime/tests_rollover_lifetime_reconfig.py
@@ -14,7 +14,7 @@
 import pytest
 
 from isctest.util import param
-from rollover.common import CDSS, DEFAULT_CONFIG, DURATION, alg, pytestmark, size
+from rollover.common import CDSS, DEFAULT_CONFIG, DURATION, pytestmark
 
 import isctest
 
@@ -43,7 +43,7 @@ def after_servers_start(ns3, templates):
         param("unlimit-lifetime", "unlimited-lifetime", 0),
     ],
 )
-def test_lifetime_reconfig(zone, policy, lifetime, alg, size, ns3):
+def test_lifetime_reconfig(zone, policy, lifetime, ns3, default_algorithm):
     config = DEFAULT_CONFIG
 
     isctest.kasp.wait_keymgr_done(ns3, f"{zone}.kasp", reconfig=True)
@@ -52,7 +52,7 @@ def test_lifetime_reconfig(zone, policy, lifetime, alg, size, ns3):
         "zone": f"{zone}.kasp",
         "cdss": CDSS,
         "keyprops": [
-            f"csk {DURATION[lifetime]} {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
+            f"csk {DURATION[lifetime]} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured zrrsig:rumoured ds:hidden",
         ],
         "nextev": None,
     }
diff --git a/bin/tests/system/rollover-multisigner/tests_rollover_multisigner.py b/bin/tests/system/rollover-multisigner/tests_rollover_multisigner.py
index 39cca867f24..20e3c357fef 100644
--- a/bin/tests/system/rollover-multisigner/tests_rollover_multisigner.py
+++ b/bin/tests/system/rollover-multisigner/tests_rollover_multisigner.py
@@ -21,7 +21,7 @@ import pytest
 
 from isctest.kasp import Iret, SettimeOptions
 from isctest.run import EnvCmd
-from rollover.common import alg, pytestmark, size
+from rollover.common import pytestmark
 from rollover.setup import fake_lifetime, render_and_sign_zone, setkeytimes
 
 import isctest
@@ -96,7 +96,7 @@ def bootstrap():
     return {}
 
 
-def test_rollover_multisigner(ns3, alg, size):
+def test_rollover_multisigner(ns3, default_algorithm):
     policy = "multisigner-model2"
     config = {
         "dnskey-ttl": timedelta(hours=1),
@@ -118,7 +118,7 @@ def test_rollover_multisigner(ns3, alg, size):
         keygen_command = [
             os.environ.get("KEYGEN"),
             "-a",
-            alg,
+            default_algorithm.name,
             "-L",
             "3600",
             "-M",
@@ -135,12 +135,14 @@ def test_rollover_multisigner(ns3, alg, size):
     isctest.kasp.check_dnssec_verify(ns3, zone)
 
     key_properties = [
-        f"ksk unlimited {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden tag-range:32768-65535",
-        f"zsk unlimited {alg} {size} goal:omnipresent dnskey:rumoured zrrsig:rumoured tag-range:32768-65535",
+        f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden tag-range:32768-65535",
+        f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured zrrsig:rumoured tag-range:32768-65535",
     ]
     expected = isctest.kasp.policy_to_properties(ttl, key_properties)
 
-    newprops = [f"zsk unlimited {alg} {size} tag-range:0-32767"]
+    newprops = [
+        f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} tag-range:0-32767"
+    ]
     expected2 = isctest.kasp.policy_to_properties(ttl, newprops)
     expected2[0].private = False
     expected2[0].legacy = True
@@ -164,7 +166,9 @@ def test_rollover_multisigner(ns3, alg, size):
     # Update zone with ZSK from another provider for zone.
     out = keygen(zone)
     newkeys = isctest.kasp.keystr_to_keylist(out)
-    newprops = [f"zsk unlimited {alg} {size} tag-range:0-32767"]
+    newprops = [
+        f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} tag-range:0-32767"
+    ]
     expected2 = isctest.kasp.policy_to_properties(ttl, newprops)
     expected2[0].private = False
     expected2[0].legacy = True
@@ -211,10 +215,10 @@ def test_rollover_multisigner(ns3, alg, size):
     isctest.kasp.check_dnssec_verify(ns3, zone)
 
     key_properties = [
-        f"ksk unlimited {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden tag-range:32768-65535",
-        f"zsk unlimited {alg} {size} goal:omnipresent dnskey:rumoured zrrsig:hidden tag-range:32768-65535",
-        f"ksk unlimited {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:omnipresent tag-range:0-32767 offset:{offval}",
-        f"zsk unlimited {alg} {size} goal:hidden dnskey:omnipresent zrrsig:omnipresent tag-range:0-32767 offset:{offval}",
+        f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden tag-range:32768-65535",
+        f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured zrrsig:hidden tag-range:32768-65535",
+        f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:omnipresent tag-range:0-32767 offset:{offval}",
+        f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent zrrsig:omnipresent tag-range:0-32767 offset:{offval}",
     ]
     expected = isctest.kasp.policy_to_properties(ttl, key_properties)
     keys = isctest.kasp.keydir_to_keylist(zone, ns3.identifier)
diff --git a/bin/tests/system/rollover-straight2none/tests_rollover_straight2none_initial.py b/bin/tests/system/rollover-straight2none/tests_rollover_straight2none_initial.py
index 8d63204a99d..b6f718c26bf 100644
--- a/bin/tests/system/rollover-straight2none/tests_rollover_straight2none_initial.py
+++ b/bin/tests/system/rollover-straight2none/tests_rollover_straight2none_initial.py
@@ -13,7 +13,7 @@
 
 import pytest
 
-from rollover.common import CDSS, DEFAULT_CONFIG, DURATION, alg, pytestmark, size
+from rollover.common import CDSS, DEFAULT_CONFIG, DURATION, pytestmark
 from rollover.setup import configure_root, configure_straight2none, configure_tld
 
 import isctest
@@ -43,7 +43,7 @@ def bootstrap():
         "going-straight-to-none-dynamic.kasp",
     ],
 )
-def test_straight2none_initial(zone, ns3, alg, size):
+def test_straight2none_initial(zone, ns3, default_algorithm):
     config = DEFAULT_CONFIG
     policy = "default"
 
@@ -53,7 +53,7 @@ def test_straight2none_initial(zone, ns3, alg, size):
         "zone": zone,
         "cdss": CDSS,
         "keyprops": [
-            f"csk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{-DURATION['P10D']}",
+            f"csk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{-DURATION['P10D']}",
         ],
         "nextev": None,
     }
diff --git a/bin/tests/system/rollover-straight2none/tests_rollover_straight2none_reconfig.py b/bin/tests/system/rollover-straight2none/tests_rollover_straight2none_reconfig.py
index b4bc988a3d8..5af41f47c99 100644
--- a/bin/tests/system/rollover-straight2none/tests_rollover_straight2none_reconfig.py
+++ b/bin/tests/system/rollover-straight2none/tests_rollover_straight2none_reconfig.py
@@ -13,7 +13,7 @@
 
 import pytest
 
-from rollover.common import CDSS, DEFAULT_CONFIG, DURATION, alg, pytestmark, size
+from rollover.common import CDSS, DEFAULT_CONFIG, DURATION, pytestmark
 from rollover.setup import configure_root, configure_straight2none, configure_tld
 
 import isctest
@@ -52,7 +52,7 @@ def after_servers_start(ns3, templates):
         "going-straight-to-none-dynamic.kasp",
     ],
 )
-def test_straight2none_reconfig(zone, ns3, alg, size):
+def test_straight2none_reconfig(zone, ns3, default_algorithm):
     config = DEFAULT_CONFIG
     policy = None
 
@@ -62,7 +62,7 @@ def test_straight2none_reconfig(zone, ns3, alg, size):
         # These zones will go bogus after signatures expire, but
         # remain validly signed for now.
         "keyprops": [
-            f"csk 0 {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{-DURATION['P10D']}",
+            f"csk 0 {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent zrrsig:omnipresent ds:omnipresent offset:{-DURATION['P10D']}",
         ],
         "nextev": None,
     }
diff --git a/bin/tests/system/rollover-zsk-prepub/tests_rollover_zsk_prepublication.py b/bin/tests/system/rollover-zsk-prepub/tests_rollover_zsk_prepublication.py
index 4ac6f673135..96db40c4cb7 100644
--- a/bin/tests/system/rollover-zsk-prepub/tests_rollover_zsk_prepublication.py
+++ b/bin/tests/system/rollover-zsk-prepub/tests_rollover_zsk_prepublication.py
@@ -17,7 +17,7 @@ import pytest
 
 from isctest.kasp import Ipub, Iret
 from isctest.util import param
-from rollover.common import TIMEDELTA, alg, pytestmark, size
+from rollover.common import TIMEDELTA, pytestmark
 from rollover.setup import configure_root, configure_tld, configure_zsk_prepub
 
 import isctest
@@ -85,7 +85,7 @@ def bootstrap():
         param("manual"),
     ],
 )
-def test_zsk_prepub_step1(tld, alg, size, ns3):
+def test_zsk_prepub_step1(tld, ns3, default_algorithm):
     zone = f"step1.zsk-prepub.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -98,8 +98,8 @@ def test_zsk_prepub_step1(tld, alg, size, ns3):
         # Introduce the first key. This will immediately be active.
         "zone": zone,
         "keyprops": [
-            f"ksk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step1-p']}",
-            f"zsk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step1-p']}",
+            f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step1-p']}",
+            f"zsk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step1-p']}",
         ],
         # Next key event is when the successor ZSK needs to be published.
         # That is the ZSK lifetime - prepublication time (minus time
@@ -118,7 +118,7 @@ def test_zsk_prepub_step1(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_zsk_prepub_step2(tld, alg, size, ns3):
+def test_zsk_prepub_step2(tld, ns3, default_algorithm):
     zone = f"step2.zsk-prepub.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -129,8 +129,8 @@ def test_zsk_prepub_step2(tld, alg, size, ns3):
         step = {
             "zone": zone,
             "keyprops": [
-                f"ksk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step2-p']}",
-                f"zsk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step2-p']}",
+                f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step2-p']}",
+                f"zsk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step2-p']}",
             ],
             "manual-mode": True,
             "nextev": None,
@@ -156,9 +156,9 @@ def test_zsk_prepub_step2(tld, alg, size, ns3):
         # zsk2 dnskey: hidden -> rumoured
         "zone": zone,
         "keyprops": [
-            f"ksk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step2-p']}",
-            f"zsk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step2-p']}",
-            f"zsk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:rumoured zrrsig:hidden offset:{OFFSETS['step2-s']}",
+            f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step2-p']}",
+            f"zsk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step2-p']}",
+            f"zsk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured zrrsig:hidden offset:{OFFSETS['step2-s']}",
         ],
         "keyrelationships": [1, 2],
         # next key event is when the successor zsk becomes omnipresent.
@@ -177,7 +177,7 @@ def test_zsk_prepub_step2(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_zsk_prepub_step3(tld, alg, size, ns3):
+def test_zsk_prepub_step3(tld, ns3, default_algorithm):
     zone = f"step3.zsk-prepub.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -188,9 +188,9 @@ def test_zsk_prepub_step3(tld, alg, size, ns3):
         step = {
             "zone": zone,
             "keyprops": [
-                f"ksk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step3-p']}",
-                f"zsk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step3-p']}",
-                f"zsk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:hidden offset:{OFFSETS['step3-s']}",
+                f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step3-p']}",
+                f"zsk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step3-p']}",
+                f"zsk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:hidden offset:{OFFSETS['step3-s']}",
             ],
             "keyrelationships": [1, 2],
             "manual-mode": True,
@@ -232,9 +232,9 @@ def test_zsk_prepub_step3(tld, alg, size, ns3):
         # zsk2 zrrsig: hidden -> rumoured
         "zone": zone,
         "keyprops": [
-            f"ksk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step3-p']}",
-            f"zsk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent zrrsig:unretentive offset:{OFFSETS['step3-p']}",
-            f"zsk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:rumoured offset:{OFFSETS['step3-s']}",
+            f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step3-p']}",
+            f"zsk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent zrrsig:unretentive offset:{OFFSETS['step3-p']}",
+            f"zsk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:rumoured offset:{OFFSETS['step3-s']}",
         ],
         "keyrelationships": [1, 2],
         # next key event is when all the rrsig records have been replaced
@@ -266,7 +266,7 @@ def test_zsk_prepub_step3(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_zsk_prepub_step4(tld, alg, size, ns3):
+def test_zsk_prepub_step4(tld, ns3, default_algorithm):
     zone = f"step4.zsk-prepub.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -277,9 +277,9 @@ def test_zsk_prepub_step4(tld, alg, size, ns3):
         step = {
             "zone": zone,
             "keyprops": [
-                f"ksk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step4-p']}",
-                f"zsk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:omnipresent zrrsig:hidden offset:{OFFSETS['step4-p']}",
-                f"zsk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step4-s']}",
+                f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step4-p']}",
+                f"zsk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent zrrsig:hidden offset:{OFFSETS['step4-p']}",
+                f"zsk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step4-s']}",
             ],
             "keyrelationships": [1, 2],
             "manual-mode": True,
@@ -308,9 +308,9 @@ def test_zsk_prepub_step4(tld, alg, size, ns3):
         # zsk2 zrrsig: rumoured -> omnipresent
         "zone": zone,
         "keyprops": [
-            f"ksk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step4-p']}",
-            f"zsk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:unretentive zrrsig:hidden offset:{OFFSETS['step4-p']}",
-            f"zsk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step4-s']}",
+            f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step4-p']}",
+            f"zsk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:unretentive zrrsig:hidden offset:{OFFSETS['step4-p']}",
+            f"zsk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step4-s']}",
         ],
         "keyrelationships": [1, 2],
         # next key event is when the dnskey enters the hidden state.
@@ -329,7 +329,7 @@ def test_zsk_prepub_step4(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_zsk_prepub_step5(tld, alg, size, ns3):
+def test_zsk_prepub_step5(tld, ns3, default_algorithm):
     zone = f"step5.zsk-prepub.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -342,9 +342,9 @@ def test_zsk_prepub_step5(tld, alg, size, ns3):
         # zsk1 dnskey: unretentive -> hidden
         "zone": zone,
         "keyprops": [
-            f"ksk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step5-p']}",
-            f"zsk {LIFETIME_POLICY} {alg} {size} goal:hidden dnskey:hidden zrrsig:hidden offset:{OFFSETS['step5-p']}",
-            f"zsk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step5-s']}",
+            f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step5-p']}",
+            f"zsk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:hidden zrrsig:hidden offset:{OFFSETS['step5-p']}",
+            f"zsk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step5-s']}",
         ],
         "keyrelationships": [1, 2],
         # next key event is when the new successor needs to be published.
@@ -366,7 +366,7 @@ def test_zsk_prepub_step5(tld, alg, size, ns3):
         param("manual"),
     ],
 )
-def test_zsk_prepub_step6(tld, alg, size, ns3):
+def test_zsk_prepub_step6(tld, ns3, default_algorithm):
     zone = f"step6.zsk-prepub.{tld}"
     policy = f"{POLICY}-{tld}"
 
@@ -378,8 +378,8 @@ def test_zsk_prepub_step6(tld, alg, size, ns3):
         # predecessor zsk is now purged.
         "zone": zone,
         "keyprops": [
-            f"ksk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step6-p']}",
-            f"zsk {LIFETIME_POLICY} {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step6-s']}",
+            f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{OFFSETS['step6-p']}",
+            f"zsk {LIFETIME_POLICY} {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent offset:{OFFSETS['step6-s']}",
         ],
         "nextev": None,
     }
diff --git a/bin/tests/system/rollover/common.py b/bin/tests/system/rollover/common.py
index 224d6a5560a..7674537f16d 100644
--- a/bin/tests/system/rollover/common.py
+++ b/bin/tests/system/rollover/common.py
@@ -11,12 +11,9 @@
 
 from datetime import timedelta
 
-import os
-
 import pytest
 
 from isctest.kasp import Ipub, IpubC, Iret
-from isctest.vars.algorithms import Algorithm
 
 pytestmark = pytest.mark.extra_artifacts(
     [
@@ -131,22 +128,3 @@ KSK_IPUB = Ipub(KSK_CONFIG)
 KSK_IPUBC = IpubC(KSK_CONFIG)
 KSK_IRET = Iret(KSK_CONFIG, zsk=False, ksk=True)
 KSK_KEYTTLPROP = KSK_CONFIG["dnskey-ttl"] + KSK_CONFIG["zone-propagation-delay"]
-
-
-@pytest.fixture
-def alg():
-    return os.environ["DEFAULT_ALGORITHM_NUMBER"]
-
-
-@pytest.fixture
-def size():
-    return os.environ["DEFAULT_BITS"]
-
-
-def default_algorithm():
-    return Algorithm(
-        os.environ["DEFAULT_ALGORITHM"],
-        int(os.environ["DEFAULT_ALGORITHM_NUMBER"]),
-        int(os.environ["DEFAULT_ALGORITHM_DST_NUMBER"]),
-        int(os.environ["DEFAULT_BITS"]),
-    )
diff --git a/bin/tests/system/rollover/setup.py b/bin/tests/system/rollover/setup.py
index 53cc97e3acd..f0953e97da0 100644
--- a/bin/tests/system/rollover/setup.py
+++ b/bin/tests/system/rollover/setup.py
@@ -16,14 +16,14 @@ import shutil
 from isctest.kasp import SettimeOptions, private_type_record
 from isctest.run import EnvCmd
 from isctest.template import Nameserver, TrustAnchor, Zone
-from rollover.common import default_algorithm
+from isctest.vars.algorithms import Algorithm
 
 import isctest
 
 
 def configure_tld(zonename: str, delegations: List[Zone]) -> Zone:
     templates = isctest.template.TemplateEngine(".")
-    alg = default_algorithm()
+    alg = Algorithm.default()
     keygen = EnvCmd("KEYGEN", f"-q -a {alg.number} -b {alg.bits} -L 3600")
     signer = EnvCmd("SIGNER", "-S -g")
 
@@ -57,7 +57,7 @@ def configure_tld(zonename: str, delegations: List[Zone]) -> Zone:
 
 def configure_root(delegations: List[Zone]) -> TrustAnchor:
     templates = isctest.template.TemplateEngine(".")
-    alg = default_algorithm()
+    alg = Algorithm.default()
     keygen = EnvCmd("KEYGEN", f"-q -a {alg.number} -b {alg.bits} -L 3600")
     signer = EnvCmd("SIGNER", "-S -g")
 
diff --git a/bin/tests/system/rollover/tests_rollover_manual.py b/bin/tests/system/rollover/tests_rollover_manual.py
index ae32dbf0e9a..87b6a93f690 100644
--- a/bin/tests/system/rollover/tests_rollover_manual.py
+++ b/bin/tests/system/rollover/tests_rollover_manual.py
@@ -11,8 +11,6 @@
 
 from datetime import timedelta
 
-import os
-
 from isctest.kasp import (
     Ipub,
     Iret,
@@ -22,7 +20,7 @@ from isctest.kasp import (
 )
 from isctest.run import EnvCmd
 from isctest.template import Nameserver, Zone
-from rollover.common import default_algorithm
+from isctest.vars.algorithms import Algorithm
 from rollover.setup import configure_root, configure_tld, setkeytimes
 
 import isctest
@@ -30,8 +28,11 @@ import isctest
 
 def setup_zone(zone, ksk_time, ksk_timings, zsk_time, zsk_timings) -> Zone:
     templates = isctest.template.TemplateEngine(".")
-    alg = default_algorithm()
-    keygen = EnvCmd("KEYGEN", f"-q -a {alg.number} -b {alg.bits} -L 3600")
+    default_algorithm = Algorithm.default()
+    keygen = EnvCmd(
+        "KEYGEN",
+        f"-q -a {default_algorithm.number} -b {default_algorithm.bits} -L 3600",
+    )
     signer = EnvCmd("SIGNER", "-S -g")
 
     isctest.log.info(f"setup {zone}")
@@ -125,10 +126,8 @@ CONFIG = {
 POLICY = "manual-rollover"
 
 
-def test_rollover_manual(ns3):
+def test_rollover_manual(ns3, default_algorithm):
     ttl = int(CONFIG["dnskey-ttl"].total_seconds())
-    alg = os.environ["DEFAULT_ALGORITHM_NUMBER"]
-    size = os.environ["DEFAULT_BITS"]
     zone = "manual-rollover.kasp"
 
     isctest.kasp.wait_keymgr_done(ns3, zone)
@@ -136,8 +135,8 @@ def test_rollover_manual(ns3):
     isctest.kasp.check_dnssec_verify(ns3, zone)
 
     key_properties = [
-        f"ksk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
-        f"zsk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
+        f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
+        f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
     ]
     expected = isctest.kasp.policy_to_properties(ttl, key_properties)
     keys = isctest.kasp.keydir_to_keylist(zone, ns3.identifier)
@@ -184,9 +183,9 @@ def test_rollover_manual(ns3):
     isctest.kasp.check_dnssec_verify(ns3, zone)
 
     key_properties = [
-        f"ksk unlimited {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
-        f"ksk unlimited {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden",
-        f"zsk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
+        f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
+        f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden",
+        f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:omnipresent",
     ]
     expected = isctest.kasp.policy_to_properties(ttl, key_properties)
     keys = isctest.kasp.keydir_to_keylist(zone, ns3.identifier)
@@ -226,10 +225,10 @@ def test_rollover_manual(ns3):
     isctest.kasp.check_dnssec_verify(ns3, zone)
 
     key_properties = [
-        f"ksk unlimited {alg} {size} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
-        f"ksk unlimited {alg} {size} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden",
-        f"zsk unlimited {alg} {size} goal:hidden dnskey:omnipresent zrrsig:omnipresent",
-        f"zsk unlimited {alg} {size} goal:omnipresent dnskey:rumoured zrrsig:hidden",
+        f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent krrsig:omnipresent ds:omnipresent",
+        f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured krrsig:rumoured ds:hidden",
+        f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent zrrsig:omnipresent",
+        f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured zrrsig:hidden",
     ]
     expected = isctest.kasp.policy_to_properties(ttl, key_properties)
     keys = isctest.kasp.keydir_to_keylist(zone, ns3.identifier)
@@ -250,10 +249,8 @@ def test_rollover_manual(ns3):
     assert "key is not actively signing" in response.out
 
 
-def test_rollover_manual_zrrsig_rumoured(ns3):
+def test_rollover_manual_zrrsig_rumoured(ns3, default_algorithm):
     ttl = int(CONFIG["dnskey-ttl"].total_seconds())
-    alg = os.environ["DEFAULT_ALGORITHM_NUMBER"]
-    size = os.environ["DEFAULT_BITS"]
     zone = "manual-rollover-zrrsig-rumoured.kasp"
 
     isctest.kasp.wait_keymgr_done(ns3, zone)
@@ -263,8 +260,8 @@ def test_rollover_manual_zrrsig_rumoured(ns3):
     koffset = -int(timedelta(days=7).total_seconds())
     zoffset = -int(timedelta(hours=2).total_seconds())
     key_properties = [
-        f"ksk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{koffset}",
-        f"zsk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent zrrsig:rumoured offset:{zoffset}",
+        f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{koffset}",
+        f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent zrrsig:rumoured offset:{zoffset}",
     ]
     expected = isctest.kasp.policy_to_properties(ttl, key_properties)
     keys = isctest.kasp.keydir_to_keylist(zone, ns3.identifier)
@@ -292,10 +289,10 @@ def test_rollover_manual_zrrsig_rumoured(ns3):
     isctest.kasp.check_dnssec_verify(ns3, zone)
 
     key_properties = [
-        f"ksk unlimited {alg} {size} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{koffset}",
+        f"ksk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:omnipresent krrsig:omnipresent ds:omnipresent offset:{koffset}",
         # Predecessor DNSKEY must stay until successor ZSK is fully omnipresent.
-        f"zsk unlimited {alg} {size} goal:hidden dnskey:omnipresent zrrsig:rumoured offset:{zoffset}",
-        f"zsk unlimited {alg} {size} goal:omnipresent dnskey:rumoured zrrsig:hidden offset:0",
+        f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:hidden dnskey:omnipresent zrrsig:rumoured offset:{zoffset}",
+        f"zsk unlimited {default_algorithm.number} {default_algorithm.bits} goal:omnipresent dnskey:rumoured zrrsig:hidden offset:0",
     ]
     expected = isctest.kasp.policy_to_properties(ttl, key_properties)
     keys = isctest.kasp.keydir_to_keylist(zone, ns3.identifier)