Kopete Off-the-Record plugin

This plugin enables Off-the-Record encryption for the KDE instant messenger Kopete.

From wikipedia:
Off-the-Record Messaging, commonly referred to as OTR, is a cryptographic protocol that provides
strong encryption for instant messaging conversations. OTR uses a combination of the AES
symmetric-key algorithm, the Diffie-Hellman key exchange, and the SHA-1 hash function. In addition
to authentication and encryption, OTR provides perfect forward secrecy and deniable encryption.
View full article.

To use this plugin you need to install libotr. libotr can be downloaded from here