TrueCrypt is a nifty free Open Source disk encryption tool. It encrypts a whole hard disk or partition and also can create virtual volumes. TrueCrypt uses encrypted container files which can be mounted like hard disks. Under Windows, you can assign a driver letter to such a virtual device. I tested version 4.1 for Windows.

Update: Please, also check out my review about TrueCrypt 5.

All in all, TrueCrypt made a very good impression to me. I sometimes encrypt important confidential data using EFS (Encrypting File System). I think, I’ll switch to TrueCrypt now. Its biggest advantage over EFS is that it hides filenames and folder structure. I also like that one only can mount an encrypted volume when the data on it is needed. This brings some extra security.

TrueCryptTrueCrypt is very easy to use. The manual has 98 pages, but I was able to use TrueCrypt without consulting it. It uses self explaining wizards to create encrypted volumes. I recommend consulting the manual though, if you use TrueCrypt regularly. You will get there, detailed information of how TrueCrypt works.

Within less than a minute, I mounted my first encrypted virtual device. TrueCrypt supports several encryption algorithms.The best known ones are AES, Blowfish and Twofish. The supported bit lengths should be secure enough for the next 100 years or so.

When creating a virtual partition, you have to specify its size. The container file occupies this space even without files in it. One shouldn’t encrypt partitions that already contain files since TrueCrypt has to format it first.

You need a password and/or a keyfile to mount an encrypted device. Any file longer than 16 Bytes is good as a keyfile. TrueCrypt can also create one for you. The advantage of using a keyfile is that it provides protection against keystroke loggers. The safest way certainly is the combination of password and keyfile. TrueCrypt even supports multiple keyfiles. This way, you can manage multi-user shared access since all users have to supply their keyfiles before the encrypted device can be mounted.

Another interesting feature of TrueCrypt are the hidden volumes. Hidden volumes reside within another TrueCrypt volume. One simply uses another password to open a hidden volume. If someone forces you to open the TrueCrypt volume, you only enter the password for the outer volume. It is not possible to prove that a TrueCrypt volume contains a hidden volume. But be careful with hidden volumes. It is possible that you overwrite the contents of a hidden volume with data from the outer volume. The manual explains how one can prevent this.

TrueCrypt is also quite fast. I tested it on a PC with a 1 GHz CPU. It took TrueCrypt 13 seconds to format a virtual disk with 200 MB using AES as encryption algorithm. I then copied 150 MB in 20 seconds to the encrypted virtual volume. Working with encrypted files didn’t seem to be slower than with unencrypted files.

TrueCrypt: Free Open Source On-The-Fly Encryption

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