swestrup | Off-The-Record-Messaging (Reply)

I haven't read the whitepapers yet, so I don't know HOW its done, but when Ian Goldberg says a new crypto messaging system has the following properties, I'm inclined to believe him:

Encryption: No one else can read your instant messages.
Authentication: You are assured the correspondent is who you think it is.
Deniability: The messages you send do not have digital signatures that are checkable by a third party. Anyone can forge messages after a conversation to make them look like they came from you. However, during a conversation, your correspondent is assured the messages he sees are authentic and unmodified.
Perfect forward secrecy: If you lose control of your private keys, no previous conversation is compromised.

This is an interesting set of features, and I'm looking forward to reading the papers on the Off-The-Record-Messaging Website when I get a chance.