My correspondents and I would like to communicate privately by email. We used to employ PGP but that might have been shooting ourselves in the foot. PGP doesn't have forward secrecy. If any of our private keys are ever compromised (by law, hacking, or rubber hose), then all our past conversations can be immediately decrypted. And our signatures shown in court.
So we switched to instant messenger conversation with Off-the-Record (OTR) messaging because it gives
No one else can read your instant messages.
You are assured the correspondent is who you think it is.
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.
As explained eloquently at http://www.cypherpunks.ca/otr/otr-wpes.pdf
Is there anything like that for email?