diff --git a/doc/src/sgml/protocol.sgml b/doc/src/sgml/protocol.sgml
new file mode 100644
index d3de330..ba95241
*** a/doc/src/sgml/protocol.sgml
--- b/doc/src/sgml/protocol.sgml
***************
*** 294,303 ****
        <listitem>
         <para>
          The frontend must now send a PasswordMessage containing the
!         password encrypted via MD5, using the 4-character salt
!         specified in the AuthenticationMD5Password message.  If
!         this is the correct password, the server responds with an
!         AuthenticationOk, otherwise it responds with an ErrorResponse.
         </para>
        </listitem>
       </varlistentry>
--- 294,306 ----
        <listitem>
         <para>
          The frontend must now send a PasswordMessage containing the
!         result of concat('md5',
!         hex_encode(md5(concat(hex_encode(md5(concat(password, username))),
!         salt)))), where salt is the 4-character salt specified in
!         the AuthenticationMD5Password message.  Username and password do not
!         include the trailing null byte.  If this is the correct password, the
!         server responds with an AuthenticationOk, otherwise it responds with
!         an ErrorResponse.
         </para>
        </listitem>
       </varlistentry>