Free open source on-the-fly encryption software
In the Volume Creation Wizard, in the password change dialog window, and in the Keyfile Generator dialog window, you can select a hash algorithm. A user-selected hash algorithm is used by the TrueCrypt Random Number Generator as a pseudorandom “mixing” function, and by the header key derivation function (HMAC based on a hash function, as specified in PKCS #5 v2.0) as a pseudorandom function. When creating a new volume, the Random Number Generator generates the master key, secondary key (XTS mode), and salt. For more information, please see the section Random Number Generator and section Header Key Derivation, Salt, and Iteration Count.
TrueCrypt currently supports the following hash algorithms: