I wrote rfc2015.el, which is supposed to fill the gap between Gnus 5.8
and mailcrypt.  Because it is not finished, I just put it in contrib
directory.

To initialize it, say
 (require 'rfc2015)
 (rfc2015-setup)

Of course, you should also initialize mailcrypt.

To sign something, say

<#part type="text/plain" disposition=inline postprocess=pgp-sign>
The text to sign.
<#/part>

To encrypt something, say

<#part type="image/jpeg" filename="to-encrypt.jpg" postprocess=pgp-encrypt>
<#/part>

TODO:
1. Verify message.
2. Automatically snarf the recipient's email address when encrypting.

Shenghuo

PS: This message is signed.  My public key is at
http://www.cs.rochester.edu/u/zsh/zsh.asc.  Unfortunately, it can not
be verified in Gnus right now. :-(