[ excerpt from developer's web site with modifications ]

Mircryption is a free encryption add-on for the popular irc clients
mIRC and XChat. Features:

- Channel text, Private query windows, DCC Chats, Actions, Topics can
all be encrypted. All crypto-related algorithms used are taken from
published, common, trusted sources. Encryption algorithm is Blowfish
(no known vulnerabilities); encryption keys are themselves stored
in encrypted form.

- Supports CBC mode encryption.

- No need to modify the way you work - text is encrypted and decrypted
automatically; encryption status of conversations is clear but
unobtrusive.

- User-friendly key management routines; menu driven and easy to
temporarily disable & re-enable encryption on a channel, send plain
text quicky, etc.

WWW: http://www.donationcoder.com/Software/Mouser/mircryption/index.php

-- lioux@FreeBSD.org