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accepted Does key renewal increase complexity of MAC forgery?
Feb
7
comment Does key renewal increase complexity of MAC forgery?
Thanks for the answer! So assuming the MAC is not broken, are (1) and (2) the only possible best attacks, depending on whether or not the tag is shorter than the key?
Jan
29
asked Does key renewal increase complexity of MAC forgery?
Jan
26
awarded  Yearling
Jan
11
comment Is finding collisions in a part-hash not often enough a bad problem?
It's not possible to get collisions "less often than expected" because I'm pretty sure this bound is the tightest possible over all probability distributions (being lowest for a uniform distribution). Either you are miscalculating the bound, or generating your values wrong, your results cannot be correct.
Dec
15
awarded  Enlightened
Dec
15
awarded  Nice Answer
Dec
14
awarded  Popular Question
Dec
10
comment Can homomorphic decryption of DES be practical?
@MaartenBodewes The algorithm doesn't need to be encrypted, but it does need to be realized as a homomorphic circuit...
Nov
14
comment Does complicating a flawed algorithm make it secure?
The answer is trivially "yes" since every secure encryption algorithm can be viewed as "added complexity" on top of the flawed identity cipher (which encrypts all plaintext to itself). But that is probably not the answer you wanted.. you need to be an expert to work out how to complicate it in a way that adds security.
Nov
12
awarded  Nice Answer
Nov
11
revised Why can't I reverse a hash to a possible input?
added 38 characters in body
Nov
11
answered Why can't I reverse a hash to a possible input?
Nov
9
comment What is the difference between “securely realizes” and “securely implements”?
You can also say "X is realized by Y" if that is less awkward to you. Ultimately it just means "to make real, concrete".
Oct
30
comment How is bitslicing faster?
@IlmariKaronen Fair enough, after reading your comments and the new answers I now agree it's sufficiently on-topic
Oct
29
comment How is bitslicing faster?
Is this really on-topic on Crypto SE?
Oct
25
comment I read ECB is bad because the same plaintext outputs the same ciphertext. Isn't that a requirement of a cipher?
I think a good addition to this answer would be to add a paragraph about how it's possible for a cipher to encrypt non-deterministically. The word "initialization vector" is referred to once and never explained.
Oct
21
comment Is there an existing cryptography algorithm / method that both encrypts AND compresses text?
The statement is correct, just somewhat awkwardly phrased. It is obvious that you cannot compress every single $n$-bit string into less than $n$ bits. You can compress some of them by exploiting redundancy (like repeated patterns of bits and so on), but others with less structure have to become larger after compression, at least by a single bit, to compensate, because information theory. So on average (and hence to guarantee correctness in all cases) the output must be as large as the input, or you will eventually truncate some input that didn't compress well (like, say, random bits).
Oct
14
answered Adding dummy bytes to ciphertext
Oct
9
comment Is there a cryptographic protocol that let's me prove someone has a large binary?
I don't have a full answer but I feel like a Merkle tree could probably tackle this kind of problem, maybe as part of some randomized protocol. Maybe someone else is more familiar with this.