TrueCrypt is an open source software to encrypt volumes of data. It even supports the creation of virtual encrypted volumes which is portable. Developed by TrueCrypt Foundation
License: Open Source
TrueCrypt is a versatile and cross-platform encryption tool that offers strong security features, but it is no longer maintained, which raises concerns about vulnerabilities. LUKS, on the other hand, is specifically designed for Linux environments, providing robust encryption through dm-crypt, but may be less user-friendly for those unfamiliar with command line operations.