Free Open-Source Disk Encryption Software For Windows Vista/XP/2000 And Linux
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.
2) No TrueCrypt volume can be identified (volumes cannot be distinguished from random data).