TrueCrypt – Free Open-Source Disk Encryption Software

TrueCrypt is a software system for establishing and maintaining an on-the-fly-encrypted volume (data storage device). On-the-fly encryption means that data is automatically encrypted or decrypted right before it is loaded or saved, without any user intervention. No data stored on an encrypted volume can be read (decrypted) without using the correct password/keyfile(s) or correct encryption keys. Entire file system is encrypted (e.g., file names, folder names, contents of every file, free space, meta data, etc).

Files can be copied to and from a mounted TrueCrypt volume just like they are copied to/from any normal disk (for example, by simple drag-and-drop operations). Files are automatically being decrypted on the fly (in memory/RAM) while they are being read or copied from an encrypted TrueCrypt volume. Similarly, files that are being written or copied to the TrueCrypt volume are automatically being encrypted on the fly (right before they are written to the disk) in RAM. Note that this does not mean that the whole file that is to be encrypted/decrypted must be stored in RAM before it can be encrypted/decrypted. There are no extra memory (RAM) requirements for TrueCrypt. For an illustration of how this is accomplished, see the following paragraph. More on official page

Feature:

• Ability to create a virtual encrypted disk within a file and mount it as a real disk
• Capable to encrypt an entire partition or storage device
• Capable to encrypt a partition or drive with installed Windows (pre-boot authentication).
• Automatic Encryption which are real-time (on-the-fly) and transparent.
• Capable of Parallelization and pipelining
• Enables plausible deniability and Hidden volume (steganography) as well as hidden operating system
• AES-256, Serpent, and Twofish Encryption algorithms that operate in TXS mode

Download : TrueCrypt

Windows 7/Vista/XP/2000/Mac OS X/Linux