TrueCrypt is free open-source disk encryption software for Windows Vista/XP, Mac OS X, and Linux
- Creates a virtual encrypted disk within a file and mounts it as a real disk.
- Encrypts an entire partition or storage device such as USB flash drive or hard drive.
- Encrypts a partition or drive where Windows is installed (pre-boot authentication).
- Encryption is automatic, real-time (on-the-fly) and transparent.
- Provides two levels of plausible deniability, in case an adversary forces you to reveal the password.
- Encryption algorithms: AES-256, Serpent, and Twofish. Mode of operation: XTS.