erc-crypt.el is a minor mode for ERC that provides PSK encryption.

Encryption can be enabled/disabled on a per buffer basis.

• Uses external OpenSSL binary for encrypt/decrypt
• Visual in-buffer indicator for errors and encrypted messages sent/received
• Auto splits ciphertext in order to get around IRC message limits. Original formatting is preserved, no information is lost.
• Messages are padded to constant size

• Move to GnuPG for symmetric encryption (and customizable key derivation from passphrase)
• Use OpenSSL for DH key generation
• Fully automated authenticated DH key exchange

erc-crypt.el should be seen as a proof-of-concept and serve as HOWTO-code in terms of developing similar minor modes for ERC. It does NOT offer strong cryptography, do NOT use this if that is what you need!

Simple and most flexible method:

;; Clone this repository, ensure directory of erc-crypt.el is in your
;; load-path and add the following to your init file:
(require 'erc-crypt)

Alternatively, you can install through MELPA or some other Emacs package manager.

Interactively

M-x erc-crypt-enable  ; Enable encryption for the current ERC buffer
M-x erc-crypt-disable ; Disable encryption for the current ERC buffer
M-x erc-crypt-set-key ; Set/change key for current ERC buffer

The code comes with a BSD-style license so you can basically do with it whatever you want.

xristos (AT) sdf (DOT) org