Which TrueCrypt Algorithm is the safest?

Question

Which TrueCrypt Algorithm is the safest to use? The performance doesn’t matter!

• AES
• Serpent
• Triple DES
• Twofish
• AES-Twofish
• AES-Twofish-Serpent
• Serpent-AES
• Serpent-Twofish-AES
• Twofish-Serpent

Answer 1

these are the results of the voting in the final round of the AES-contest:

Rijndael 86-10 = 76
Serpent 59-7   = 52
Twofish 31-21 = 10
RC6 23-37 = -14
MARS 13-83 = -70 

(http://csrc.nist.gov/archive/aes/round2/comments/20000523-msmid-2.pdf, linked via truecrypt serpent, read that one as well).

so, for a variety of reason Rijndael became AES, which is the successor of DES (and 3DES).

and, just because it popped up today on news.ycombinator.com, the story of AES:

http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html

Answer 2

Using TrueCrypt 7.0a, the most secure method of encryption is: Use the AES-Twofish-Serpent cascading encryption with the XTS method. Use the Whirlpool hash algorithm. (SHA-512 is a very close 2nd place here... it's debatable... I'm leaning towards Whirlpool because SHA-512 is already having a successor developed because of fears that it is based on an older SHA-1 that has been compromised.) MOST IMPORTANT is to use a VERY strong password. 20 to 30+ characters, uppercase, lowercase, numbers, symbols. Use Microsoft's online password checker for a strength test. You can also use Keyfiles to further secure your password.

I recommend the AES-Twofish-Serpent over the Serpent-Twofish-AES because you want the outermost encryption (AES will be the first layer they need to break) to be the most standard in the industry. That one is the most tried and true and the most tested of all of them. Plus, if someone assumes a file is encrypted with AES, there's no way of seeing that is is then encrypted with Twofish... so they do all this work to break the AES, only to find that Twofish stands in their way now. And then again after Twofish they run into Serpent, which is the biggest beast of them all (even though it is less used / tested than AES, it still has a much higher security margin than AES)

If you do use Keyfiles, I'd recommend having TrueCrypt create 3 keyfiles for you. Create one keyfile for each hash algorithm they provide. You might also add some .jpg's and some .mp3 files as well. I would make sure to make each keyfile read-only however.

This is probably overkill though.

Answer 3

The cascaded ciphers (AES-Twofish-Serpent, etc.) should be the most secure. Your data is encrypted with one algorithm, then the output from that is encrypted with the second algorithm, whose output is encrypted with the third algorithm. According to the TrueCrypt documentation, each algorithm uses a different key, each derived from your passphrase.

If a vulnerability is found in one (or two) of these ciphers, your data should still be secure, as an attacker would still not be able to break the remaining ciphers.

Answer 4

I've read that chaining algorithms together may result in weaker security due to the algorithm used to follow one with the other.

Further, the efficiency and speed will take a large hit if you used one of the combined ciphers.

I would recommend either Rijndael (AES) or Serpent and if you want it to be secure: the most crucial element is the key so make a very long key with at least one of each set of upper and lower case, number and symbol characters.

Answer 5

Rijndael won the AES competition primarily because it's the fastest and easiest to implement in hardware, not because it's the most "secure." Twofish and Serpent are usually considered more secure, but since they are all extremely rock-solid, that's a very subjective claim. And of course, encrypting with multiple algorithms will be even more "secure," but will reduce the speed even further.

Again, they're all rock-solid, so my advice would be to just go with whichever is fastest on your machine (usually AES).

Answer 6

After a quick search I'd say AES 256 bits.

I would avoid Triple AES and Triple blowfish. Running the same algorithm multiple times may result in less security then using the original algorithm one time.

source

Answer 7

Although there are some dangers in cascading multiple ciphers together, Truecrypt appears to deal with them as best it can. It doesn't add any known plaintexts to the output of the first cipher and it uses indepentant keys for each so by chaining the different algorithms together it should increase the security.

I would stear clear of 3DES though. Having read the Truecrypt page listing the choices of algorithm it doesn't even list triple DES so they may have recently removed it.

Answer 8

Either AES-Twofish-Serpent or Serpent-Twofish-AES. But regular AES is sufficient.