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Jan
14
comment Possible to use an accumulator to “license” or restrict the qty of certificates being used?
This answer doesn't work. I think you are confused about what a $n$-time signature scheme is. A $n$-time signature scheme is a signature scheme that is secure as long as it is used only $n$ times. There is no guarantee that it's impossible to sign $n+1$ messages, and indeed every $n$-time signature scheme I've ever seen does allow signer to sign $n+1$ messages if he wishes (though this could enable others to forge additional signatures).
Jan
14
answered Formal security of recycled random blinding in a Paillier scheme
Jan
14
reviewed Approve TimeStamp in Cache-time attacks on AES
Jan
14
comment TimeStamp in Cache-time attacks on AES
This question appears to be off-topic because it is about the meaning of Intel x86 assembly instructions; this site is for questions about cryptography.
Jan
13
comment Automated testing of cipher security for import/export compliance
@TruthSerum, I still don't get it. In what sense does my answer not answer your question? Everything I wrote still applies. No, there is no known way to automatically test and grade the security of an arbitrary cipher. That's not how we do it in practice. Perhaps if you elaborate the question it will become clearer what you are looking for and/or why you think this doesn't answer the question?
Jan
13
comment Automated testing of cipher security for import/export compliance
@TruthSerum, you didn't state that in the question. Please edit your question, and this time make sure all relevant information is included in the question. Actually, I'm finding it difficult to guess exactly what you are asking or looking for. This is starting to look like a "chameleon question" (one that changes each time someone adds an answer); that's discouraged on this site and may discourage people from answering.
Jan
13
answered Automated testing of cipher security for import/export compliance
Jan
6
comment (Re-)Using deterministic IV in CTR mode / How to: deterministic AES
@SebastianS, if you have requirements on how much expansion is allowed (how much longer the ciphertext can be than the plaintext), then state that in the quesiton. Don't assume that convergent encryption cannot meet those requirements; there are certainly convergent encryption schemes with relatively small expansion. Nothing forces you to have 256 bits of expansion. Don't judge all of convergent encryption by one particular scheme with one particular set of parameters.
Jan
6
answered Why is the private key generated first in public key crypto?
Jan
6
comment (Re-)Using deterministic IV in CTR mode / How to: deterministic AES
@SebastianS, I can't understand what you are saying (your requirements do not seem to be stated very clearly, and I can't understand why you are rejecting convergent encryption), so I'm afraid I don't know how to help you. If you would like further help, I encourage you think about how to formulate your problem more precisely, and then edit the question.
Jan
6
comment What is the difference between CSPRNG and PRNG?
@cpast, I don't think that question (or the answer there) will help people with the confusion that my question is intended to get at. For instance, think of a typical reader who sees some awesome statistical PRNG (say, Mersenne twister) and thinks, hey, I bet I could use this for cryptography! I don't think the answer there is going to help them understand why that's a bad idea, and I don't think the question there will be meaningful to them. The question there also is a bit confused/unclear (a PRNG for key generation? no -- we use a CSPRNG for that). I think this is a better formulation.
Jan
5
comment (Re-)Using deterministic IV in CTR mode / How to: deterministic AES
@SebastianS, I can't understand what you are saying. (If you generate the IV as a hash of the plaintext, you'll still need to store it somewhere too, so I don't understand what your requirements/objections are.)
Jan
5
comment Is BBS used for generation of keys for any modern cryptosystem?
@111, right, but: if it doesn't have a security proof, then BBS has no advantages over competing schemes, so there would be no good reason to choose BBS.
Jan
5
asked Difference between statistical PRNG and cryptographic PRNG?
Jan
5
answered Is BBS used for generation of keys for any modern cryptosystem?
Jan
5
answered (Re-)Using deterministic IV in CTR mode / How to: deterministic AES
Jan
5
comment Luby-Rackoff on Feistel ciphers
Can you provide a self-contained description of the claim in those lecture notes (without requiring us to click elsewhere, and without relying upon a link that could disappear at any time)? How many rounds are we talking about? What kind of Feistel cipher?
Jan
5
answered Analyzing security flaws of cipher
Dec
29
awarded  Populist
Dec
22
comment Why shouldn't I use ECB encryption?
1. This is not good advice. Using encryption without authentication disregards about a decade of advice from cryptographers. Better would be to use authenticated encryption, as Ilmari Karonen recommends. 2. This answer seems to be superceded by Ilmari Karonen's answer.