Best software for encrypting your drive with best encryption methods.
TrueCrypt software system is making and maintaining quick encrypted volume (data storage device). Data is automatically encrypted before it is saved and decrypted after it is loaded, without any work on by user. Data stored on an encrypted volume can not be read (decrypted) without using the correct password/keyfile(s) or correct encryption keys.
It is tottaly free software.
Download from following
