VeraCrypt - VeraCrypt is a free open source disk encryption software for Windows, Mac OSX and Linux.
BitTorrent - BitTorrent is a peer-to-peer program developed by Bram Cohen and BitTorrent, Inc.
Axcrypt - AxCrypt - Password Protect Files With Strong Encryption. AxCrypt is the leading open source file encryption software for Windows.
Soulseek - Soulseek® is a unique ad-free, spyware free, and just plain free file sharing application.
Windows BitLocker - This topic provides a high-level overview of BitLocker, including a list of system requirements, practical applications, and deprecated features.
Shareaza - Shareaza is the most luxurious and sophisticated file sharing system you'll find.