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18/20 answers
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Oct
17
awarded  Suffrage
Oct
17
awarded  Vox Populi
Oct
16
revised How was the complexity of the Biclique Attack calculated?
Fixed complexity figure to account for success rate (100% vs 50%).
Oct
16
awarded  Necromancer
Oct
15
awarded  Revival
Oct
15
awarded  cryptanalysis
Oct
15
comment Increase number of rounds for SPN and Feistel ciphers
@marluh: slowing down both the attacker and the defender by the same factor is not good security. We do it with password hashing because we know not how to do better, but we really prefer when the attacker is slowed down exponentially -- and that's what happens with a larger key. A 128-bit key is enough to defeat brute force utterly (by a large margin) so slowing down produces no tangible security gain: if the system gets broken, it won't be through brute force. However, slowing down has quite tangible drawbacks (namely, things go slower for the defender, too).
Oct
14
answered How was the complexity of the Biclique Attack calculated?
Oct
14
answered Increase number of rounds for SPN and Feistel ciphers
Oct
14
answered Can I save space for short messages by using encryption with private key instead of a signature?
Oct
12
comment What is the recommended replacement for MD5?
Of course it really depends on what you mean by "standard" hash function; but some of the SHA-3 candidates offer extension for a 160-bit output size (e.g. Shabal) and, being SHA-3 candidates, they have reasonably clear specifications with test vectors and sample implementations.
Oct
10
comment understanding a length extension attack
I imagine with my brain. That's the point of imagining: I don't have to do it for real. If I knew m, I could build the larger message. Application is given in the end of my answer: I don't know the MAC key but I can still forge a message by imagining I know it, and computing the MAC value that I would have obtained.
Oct
10
awarded  Enlightened
Oct
10
awarded  Nice Answer
Oct
9
answered How is it possible to parallelize a hashing function to crack an iteratively hashed password?
Oct
7
answered understanding a length extension attack
Oct
6
awarded  Enlightened
Oct
6
awarded  Nice Answer
Oct
5
awarded  Nice Answer
Oct
4
answered Besides key and ciphertext sizes what are other advantages of elliptic curve versions of various protocols?