Libgadu 1.10 (not-yet-released) brings us a few extra features that were implemented in Gadu-Gadu protocol for GG10. We have decided to include these in Kadu, but only for people with 1.10.0-pre version of libgadu installed.
TLS in an encryption protocol used in HTTPS connections. GaduGadu 10 can use it to secure connection between client and server. Each message is decrypted at GG server and then encrypted for the second client (if it also supports TLS connection). This is not ideal solution, but at least it allows for real secure login.
Second level of protection is Kadu's encryption plugin that allows for sending and receiving encrypted messages - this is client-to-client encryption - messages can be decrypted only by receiver (this is supported only by Kadu and EKG messengers).
I hope these two levels of protection are enough for everyone ;)
GaduGadu 10 also supports multilogon. Multiple clients can be logged on one account (before GG10 each login would disconnect other clients). Received messages are sent to each of the client and sent messages are broadcasted between them. Latest git versions of Kadu support this new broadcast message.
Kadu can also notify you about every other connection, both by our notification system and by new special multilogon window. Each session can be disconnected by Kadu both in window and in notifications.