doc: Remove links to further reading from pgcrypto docs

The pgcrypto docs contained a set of links for useful reading and
technical references. These sets of links were however not actively
curated and had stale content and dead links. Rather than investing
time into maintining these, this removes them altogether since there
are lots of resources online which are actively maintained.

Backpatch to all supported versions since these links have been in
the docs for a long time.

Reported-by: Hanefi Onaldi <hanefi.onaldi@microsoft.com>
Reviewed-by: Magnus Hagander <magnus@hagander.net>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/170774255387.3279713.2822272755998870925@wrigleys.postgresql.org
Backpatch-through: v12

diff --git a/doc/src/sgml/pgcrypto.sgml b/doc/src/sgml/pgcrypto.sgml
index 43fb8dbe66617debb594727b6248c428e89dc220..0d5c0e0b45bc7be7d7978af35b16dabd3572801c 100644 (file)
--- a/doc/src/sgml/pgcrypto.sgml
+++ b/doc/src/sgml/pgcrypto.sgml
@@ -1220,72 +1220,6 @@ gen_random_uuid() returns uuid
     ciphertexts of a given size.
    </para>
   </sect3>
-
-  <sect3>
-   <title>Useful Reading</title>
-
-   <itemizedlist>
-    <listitem>
-     <para><ulink url="https://www.gnupg.org/gph/en/manual.html"></ulink></para>
-     <para>The GNU Privacy Handbook.</para>
-    </listitem>
-    <listitem>
-     <para><ulink url="https://www.openwall.com/crypt/"></ulink></para>
-     <para>Describes the crypt-blowfish algorithm.</para>
-    </listitem>
-    <listitem>
-     <para>
-      <ulink url="https://www.iusmentis.com/security/passphrasefaq/"></ulink>
-     </para>
-     <para>How to choose a good password.</para>
-    </listitem>
-    <listitem>
-     <para><ulink url="http://world.std.com/~reinhold/diceware.html"></ulink></para>
-     <para>Interesting idea for picking passwords.</para>
-    </listitem>
-    <listitem>
-     <para>
-      <ulink url="http://www.interhack.net/people/cmcurtin/snake-oil-faq.html"></ulink>
-     </para>
-     <para>Describes good and bad cryptography.</para>
-    </listitem>
-   </itemizedlist>
-  </sect3>
-
-  <sect3>
-   <title>Technical References</title>
-
-   <itemizedlist>
-    <listitem>
-     <para><ulink url="https://tools.ietf.org/html/rfc4880"></ulink></para>
-     <para>OpenPGP message format.</para>
-    </listitem>
-    <listitem>
-     <para><ulink url="https://tools.ietf.org/html/rfc1321"></ulink></para>
-     <para>The MD5 Message-Digest Algorithm.</para>
-    </listitem>
-    <listitem>
-     <para><ulink url="https://tools.ietf.org/html/rfc2104"></ulink></para>
-     <para>HMAC: Keyed-Hashing for Message Authentication.</para>
-    </listitem>
-    <listitem>
-     <para>
-      <ulink url="https://www.usenix.org/legacy/events/usenix99/provos.html"></ulink>
-     </para>
-     <para>Comparison of crypt-des, crypt-md5 and bcrypt algorithms.</para>
-    </listitem>
-    <listitem>
-     <para>
-      <ulink url="https://en.wikipedia.org/wiki/Fortuna_(PRNG)"></ulink>
-     </para>
-     <para>Description of Fortuna CSPRNG.</para>
-    </listitem>
-    <listitem>
-     <para><ulink url="https://jlcooke.ca/random/"></ulink></para>
-     <para>Jean-Luc Cooke Fortuna-based <filename>/dev/random</filename> driver for Linux.</para>
-    </listitem>
-   </itemizedlist>
-  </sect3>
  </sect2>
 
  <sect2>