Free open-source disk encryption software for Windows XP/2000/2003 and Linux.

* http://www.truecrypt.org/

Version 5 released on 5 Feb 2008, now adds system partition encryption for Windows XP/2003/Vista.

From the web site, main features:
* It can create a virtual encrypted disk within a file and mount it as a real disk.
* It can encrypt an entire hard disk partition or a device, such as USB memory stick, floppy disk, etc.
* Provides two levels of plausible deniability, in case an adversary forces you to reveal the password:
		1 Hidden volume
		1 No TrueCrypt volume can be identified (TrueCrypt volumes cannot be distinguished from random data).
* Encryption algorithms:
** AES-256,
** Blowfish (448-bit key),
** CAST5,
** Serpent (256-bit key),
** Triple DES, and
** Twofish (256-bit key).
* Mode of operation: LRW  (CBC supported as legacy).
* Based on Encryption for the Masses (E4M) 2.02a, which was conceived in 1997.

From EncryptingPersonalWiki:
* Very, very, good product
* Needs Administrator-rights for Install AND USE
* May have trouble dismounting a container
** sometimes trouble with handles not letting go
** If so, the solution is
*** log-off current user
*** re-log-on as same user
*** dismount as normal.
** Hopefully this will be fixed in the next soon-to-be release.

----
	 :	"No TrueCrypt volume can be identified (TrueCrypt volumes cannot be distinguished from random data)."

The problem here being that the 'random' of an encrypted volume is likely to be much closer to truly random than actual normal blank disk space would be.  Really, the only thing I can think of off hand that would produce random data on a (still usable) drive would be a file wiper, and probably a poorly written one at that (if I recall correctly, you don't want to write purely random data if your goal is to make recovery very expensive, but I've been wrong before).  

As is typical, this doesn't mean the package is a fraud, useless, etc, it just means that you have to be careful before you accept every claim made by even a good package.

--WilliamUnderwood