A Freeware, Free open-source disk encryption software for Windows 7/Vista/XP, Mac OS X, and Linux.
Main Features: 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. Parallelization and pipelining allow data to be read and written as fast as if the drive was not encrypted. Encryption can be hardware-accelerated on modern processors. Provides plausible deniability, in case an adversary forces you to reveal the password: Hidden volume (steganography) and hidden operating system. More information about the features of TrueCrypt may be found in the documentation.
NOTE: This version is for Windows 7/Vista/XP/2000 to get updated versions or different OS plus to: Download the Latest Secure and Stable Version of TrueCrypt ... click the little house (Below Right) to get to T r u e C r y p t's Download page and website.