TrueCrypt - Free open-source disk encryption software for Windows 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.
- Provides plausible deniability, in case an adversary forces you to reveal the password:
- Hidden volume (steganography) and hidden operating system.
- Encryption algorithms: AES-256, Serpent, and Twofish. Mode of operation: XTS.
Advantages:
- Free
- Strong protection due to encryption
- Very powerful
Disadvantages:
- Password: Like with any other encryption software, if you lose your password, you won't be able to access your files.
- Full encryption means that it might take lots of time to decrypt. *
* Files are automatically being decrypted on the fly (in memory/RAM) while they are being read or copied from an encrypted TrueCrypt volume. There are no extra memory (RAM) requirements for TrueCrypt. Let's suppose that there is an .avi video file stored on a TrueCrypt volume (therefore, the video file is entirely encrypted). The user provides the correct password (and/or keyfile) and mounts (opens) the TrueCrypt volume. When the user double clicks the icon of the video file, the operating system launches the application associated with the file type – typically a media player. The media player then begins loading a small initial portion of the video file from the TrueCrypt-encrypted volume to RAM (memory) in order to play it. While the portion is being loaded, TrueCrypt is automatically decrypting it (in RAM). The decrypted portion of the video (stored in RAM) is then played by the media player. While this portion is being played, the media player begins loading next small portion of the video file from the TrueCrypt-encrypted volume to RAM (memory) and the process repeats. This process is called on-the-fly encryption/decryption and it works for all file types, not only for video files.