otr4j is an implementation of the OTR (Off The Record) protocol in java.
Off-the-Record Messaging, is a cryptographic protocol that uses a combination of the Advanced Encryption Standard (AES), the Diffie-Hellman key exchange, and the SHA hash functions. In addition to authentication and encryption, OTR provides perfect forward secrecy and malleable encryption. The OTR protocol was designed by Ian Goldberg and the OTR Development Team.
otr4j development started during the Google Summer of Code 2009 where the goal was to add support for OTR in SIP Communicator (now called jitsi).
Recently, devrandom from the Guardian project ported SMP support from java-otr to otr4j and redsolution moved the project to github and did various fixes.
Other people might have added features to otr4j too so I move upstream here to github in an effort to facilitate people contributing back to the project.
If you use maven for managing your project lifecycle and you want to use otr4j in your project, just add the following repository entry to the pom.xml:
<repository>
<id>otr4j-repo</id>
<name>otr4j repository on GitHub</name>
<url>http://gpolitis.github.com/otr4j/repository/</url>
</repository>