First announced as an pre-alpha last year, BitTorrent's encrypted messaging system is finally ready for prime time. The latest release "solve[s] serverless peer-to-peer messaging," according to the official BitTorrent blog. It wraps text, images, and voice calls in a comforting layer of encryption that's hopefully free of NSA influence.
There are no servers to compromise; all messages and encryption keys are stored locally instead of in the cloud. Despite this decentralized nature, the system still has provisions for delivering messages to offline users.
Bleep's first wide release adds Whispers, limited-time messages that self-destruct after 25 seconds. An extra layer of privacy prevents the whisperer's user name and message from being captured in the same screenshot, but it seems like recipients could easily take two shots of anything incriminating. I dunno, maybe you shouldn't be whispering anything you're not prepared to share with the rest of the class.
If you want to try Bleep for yourself, the client is available here for Windows, OS X, Android, and iOS. No more than a user name is required to get started, though email and mobile verification are both optional.