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I like crypto. Need I say more?


Apr
15
comment Has there ever been more then a theortetical difference between preimage resistance and second preimage resistance?
Clearly having the message content could help. It has helped in some theoretical attacks (see here). Not sure if it has ever helped in practical situations.
Apr
13
reviewed Approve suggested edit on Why do some block cipher modes of operation only use encryption while others use both encryption and decryption?
Apr
11
comment Can I use Shamir's secret sharing scheme for multiplicative homomorphism for secure multiparty computation?
@nie_11 I was never able to find a paper on multiplicative secret sharing which is why I asked about it here. In some sense, multiplicative secret sharing is just additive secret sharing in a multiplicative group. Which leads us to 0 (and something I hadn't thought about previously). If we consider the multiplicative group of integers modulo some $n$, 0 is not in that group. So it makes sense 0 won't work.
Apr
10
comment Is it possible to deduce the IV from CBC ciphered data, without knowing the key?
@figlesquidge I think it is fine. Ideally questions like that would have been migrated here, but I don't think this site was up yet. It would be a good question for our site. Someone could always post a similar question here.
Apr
9
revised What are some disadvantages of homomorphic encryption schemes?
deleted 55 characters in body
Apr
9
comment Is it possible to deduce the IV from CBC ciphered data, without knowing the key?
@ddddavidee I was going to suggest you post that as a question on here, but I found the question & answer on stack overflow (stackoverflow.com/questions/3008139/…).
Apr
8
answered Is it possible to deduce the IV from CBC ciphered data, without knowing the key?
Apr
8
comment Is it possible to deduce the IV from CBC ciphered data, without knowing the key?
If you "do not ship the IV" how does someone decrypt?
Apr
7
answered Compression step of PGP
Apr
7
comment Compression step of PGP
@archie This question specifically asks about authentication. The question you linked to is more general. The answers there don't really address authentication. I'm guessing the OP is thinking that creating two messages with the same compressed version is easier than a traditional (hash function) collision attack. The idea being that perhaps if you had two messages with the same compressed version, then the signature would be the same. Perhaps the OP can comment.
Apr
7
answered Can I use Shamir's secret sharing scheme for multiplicative homomorphism for secure multiparty computation?
Apr
7
revised How could Fully Homomorphic Encryption support power operations?
added 451 characters in body
Apr
7
comment How could Fully Homomorphic Encryption support power operations?
@JianLiu BGV does. I'm not sure about others.
Apr
7
answered How could Fully Homomorphic Encryption support power operations?
Apr
4
awarded  Enlightened
Apr
4
awarded  Nice Answer
Mar
28
comment Is Encryption without knowing the input directly possible at all?
cleaned up some comments as they were incorporated into the question
Mar
26
comment m ∈ Zn \Z*n, RSA works but not secure
You may find this related question interesting and helpful.
Mar
26
comment m ∈ Zn \Z*n, RSA works but not secure
$\varphi(p)$ is the number of numbers smaller than $p$ which are co-prime to $p$. $p$ is prime, so every number smaller than $p$ is co-prime to $p$ (by the definition of prime), so $\varphi(p)=p-1$.
Mar
24
reviewed Satisfactory simple multiplication in GF(8)