Un interessante programma per criptare i dati, completamente open.
Estratto dal loro sito:

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Free open-source disk encryption software for Windows Vista/XP/2000 and Linux 
Main Features:
Creates a virtual encrypted disk within a file and mounts it as a real disk.

Encrypts an entire hard disk partition or a storage device such as USB flash drive.

Encryption is automatic, real-time (on-the-fly) and transparent.

Provides two levels of plausible deniability, in case an adversary forces you to reveal the password:

1) Hidden volume (steganography – more information may be found here).

2) No TrueCrypt volume can be identified (volumes cannot be distinguished from random data).

Encryption algorithms: AES-256, Serpent, and Twofish. Mode of operation: LRW.
Further information regarding features of the software may be found in the documentation.

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Maggiori info: http://www.truecrypt.org/