RetroShare is a Open Source cross-platform, private and secure decentralised communication platform.
It lets you to securely chat and share files with your friends and family, using a web-of-trust to authenticate peers and OpenSSL to encrypt all communication.
RetroShare provides filesharing, chat, messages, forums and channels.
Features:
* Serverless, encrypted Chat & Filetransfer
* Multiple simultaneous downloads / uploads
* Search Friends
* Messages
* Forums
* UPnP / NAT-PMP Port Forwarding support
* GnuPG Authentication
* OpenSSL Encryption
* plugins support
* Graphical User Interface written with Qt4 toolkit
* System tray integration.