RetroShare is open source software for encrypted filesharing, serverless email, instant messaging, online chat, and BBS, based on a friend-to-friend network built on GNU Privacy Guard (GPG). Developed by DrBob
License: Open Source
Tox is primarily focused on secure communication through chat, voice, and video, while RetroShare offers a broader range of features including file sharing and forums in a decentralized environment. Both prioritize privacy and security but cater to different user needs.