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Hash.Type....: descrypt, DES(Unix), Traditional DES Speed.GPU.#1.: 6215.8k/s

Hash.Type....: SHA-3(Keccak) Speed.GPU.#1.: 20514.1k/s


It looks like you can make attempts crack SHA-3 (keccak) 3 times faster than DES. While Keccak is known as a very strong crypto and DES a very weak crypto.

How do you explain this?

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closed as off-topic by Adi, Xander, Lucas Kauffman, Rory Alsop Aug 2 '13 at 19:26

  • This question does not appear to be about Information security within the scope defined in the help center.
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you're comparing apples with pears – Lucas Kauffman Aug 2 '13 at 18:47
This question appears to be off-topic because answering it would require a dive into the basic concepts of cryptographic primitives. I believe that some reading on the subjects would help you a lot, and then if you have a question, you're welcome to ask. Your question doesn't show the minimum amount of understanding regarding the subject. – Adi Aug 2 '13 at 18:48
@LucasKauffman more like apples to lego bricks – AJ Henderson Aug 2 '13 at 18:49
@user129789 - DES is not a hashing algorithm and can not be used as such. It is non-reductive. LanMan is poorly described as a hash, though it doesn't reduce the data set as the output is 16 bytes and describes a 14 byte input. By definition, hashes should reduce the length of the input for any input longer than the hash length. DES output is the same length as the input. – AJ Henderson Aug 2 '13 at 19:04
@AJHenderson LM hashes, are considered hashes.... – user129789 Aug 3 '13 at 2:31

SHA-3 is a hashing algorithm. DES is an encryption algorithm. The two are not comparable. They do different things and do them in different ways.

It's a bit like asking why your blender is faster than your bicycle.

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DES is sometimes used as a hash algorithm. – user129789 Aug 3 '13 at 2:44
I think OP got confused because SHA-3 is a cryptographic hash function. ;) – e-sushi Aug 16 '13 at 23:12

This is the number of attempts per second. It does not take in to account less than brute force attacks against the algorithms or the total effective keyspace of the algorithms. It only takes in to account the difficulty of performing the actual calculation. Since SHA-3 is a hash, it is fairly simple to computer where as DES is an encryption operation and is much more computationally difficult per attempt.

It also doesn't take in to account a hash is not the same as an encryption algorithm, so they are not even remotely comparable, but even if they were, it wouldn't say anything about the security.

The difference in security between them comes from weaknesses that allow for an effective reduction of keyspace (ie, the number of attempts that need to be made). If I have one algorithm that takes 5 minutes to make 1 attempt, but only has 10 possible keys, it will only take me 50 minutes to crack it (on average, only 25 minutes). If on the other hand I have an algorithm that I can make 1000 tries per second, but I have to try a trillion possibilities, I'm going to be sitting around trying for a very long time.

A theoretically perfect encryption algorithm should be indistinguishable from random. If there is a 8 bit key for example, it should require 128 tries on average to find a match in the 256 possible keys. However, problems in the algorithms tend to reduce this by either small or large amounts, so instead of requiring 128 tries, maybe half of the keys can be determined to not match easily, in this case, it now only takes 64 tries on average because the effective key space is reduced to 7 bits. These kinds of problems are what make encryption algorithms more or less secure when compared to a theoretical perfect algorithm.

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DES is sometimes used as a hash algorithm. – user129789 Aug 13 '13 at 3:56

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