Calypso is a cross platfrom file sharing client using the anonymous network MUTE. Developed using C++ and Qt, Calypso is portable to Windows, Linux, and other environments.
License: Open Source
Calypso is a paid VPN service offering advanced encryption and a no-logs policy, making it ideal for privacy-conscious users. UltraSurf, on the other hand, is a free tool that focuses on bypassing geo-restrictions but may have limited privacy features.