Add some more text about identity privacy

diff --git a/raddb/sites-available/eap-aka-sim b/raddb/sites-available/eap-aka-sim
index ced6329cf87c46c20605ad0ad80707040491099a..afee4e19990f799a580911ccb5d891c49f910eac 100644 (file)
--- a/raddb/sites-available/eap-aka-sim
+++ b/raddb/sites-available/eap-aka-sim
@@ -366,6 +366,25 @@ server eap-aka-sim {
        #  to execute the `load session { ... }` section next.  This is
        #  sometimes useful when dealing with non-standard fastauth identities.
        #
+       #  #### Custom identity schemes
+       #
+       #  Multiple identity privacy schemes have been proposed for
+       #  EAP-SIM/AKA/AKA'.  Instead of hard coding implementations in the server
+       #  source we've provided the necessary cryptographic functions for them to be
+       #  implemented in policy.
+       #
+       #  The notable exception to this is the scheme described in
+       #  3GPP TS 33.234 which is supported via the following expansions functions:
+       #
+       #  - 3gpp_temporary_id_key_index
+       #  - 3gpp_temporary_id_decrypt
+       #  - 3gpp_temporary_id_encrypt
+       #
+       #  The rlm_cipher module and the &control.KDF-Identity attribute override
+       #  (see notes below) are provided to allow the "Privacy Protection for EAP-AKA"
+       #  scheme described by 3GPP S3-170116 and the Wireless Broadband Allowance
+       #  document "IMSI PRIVACY PROTECTION FOR WI-FI".
+       #
        recv Identity-Response {
                ok
        }
@@ -556,7 +575,18 @@ server eap-aka-sim {
        #  message, or sent as an AT_IDENTITY value. One such identity privacy
        #  scheme described by 3GPP S3-170116 "Privacy Protection for EAP-AKA",
        #  where the cryptographic identity is the plaintext extracted from
-       #  the encrypted identity blob.
+       #  the encrypted identity blob.  The same behaviour is required for the
+       #  evolution of that standard published by the WBA
+       #  "IMSI PRIVACY PROTECTION FOR WI-FI".
+       #
+       #  Both standards as implemented in iOS and Android violate RFC 4186,
+       #  RFC 4187,and RFC 5448 in requiring that the Identity input to the
+       #  cryptographic function used to derive the MK for the session be set
+       #  to the decrypted identity, not the last value of AT_IDENTITY as
+       #  stated by the original RFCs.
+       #
+       #  No where is this mentioned in either the original 3GPP proposal or the
+       #  WBA document.
        #
        #  If you need to implement one of these identity privacy schemes, the
        #  cryptographic identity can be specified with `&control.KDF-Identity`.