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I like crypto. Need I say more?


57m
comment Decrypting a small Message using RSA with a Private Key
In step 9, why are you raising to the 3?
2d
comment What is the asymptotic complexity of RSA and paillier cryptosystem algorithm?
@user11236 Take a look at Ch 14 of HAC
2d
comment What happens if biometric data is stolen?
There has been some work where your biometric is used as your public key. Then it doesn't matter if your biometric data is stolen as that is your public key. It uses IBE under the hood and some other things to deal with the fuzziness of biometrics.
2d
comment Could program verification techniques prevent bugs of the genre of Heartbleed from occurring?
@Gilles, I sent it your way to CS. Probably should have the comments wiped (give you a clean slate there).
2d
comment Decrypt Passwords based on using a user's password
I'm going to migrate your question over to IT Security as I think you'll get better attention there. While it relates to crypto, our site is primarily about the theoretical aspects of cryptography. IT Security is a much better site for something like this. Head over there and register for an account so you can track answers, etc.
2d
comment Decrypt Passwords based on using a user's password
Let me see if I get this straight. The employee enters their password which gives them the key to encrypt/decrypt the customer's password. All employees will likely have different passwords though, correct?
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
15
comment Could program verification techniques prevent bugs of the genre of Heartbleed from occurring?
I think your question is off topic. It is only tangentially related to crypto. Not sure if there is a good site for it on SE though.
Apr
14
comment Certificate Revocation List
Sam, I'm going to migrate your question to IT security. This site is more about the theory of cryptography. The IT Security site (among other things) deals a lot with practical issues in cryptography.
Apr
14
comment Compute in GF(2^8)
Take a look at this question. Also, any textbook on abstract algebra will probably help.
Apr
14
comment Compute in GF(2^8)
Is it just division in GF(2^8) that you are having troubles with? I.e., do you know how to add, subtract and multiply in the field?
Apr
14
comment Compute in GF(2^8)
I don't really see a question here. Are you wanting to perform the computation modulo $P(x)$ and don't know how? Is this homework? If not, software packages like SAGE will perform the computation for you. Or do you just want to know how the math works? Other than using the AES irreducible polynomial, what does this have to do with cryptography?
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 After heartbleed, how can you safely distribute new certs?
@ConditionRacer, your question is better suited for IT Security. I'll migrate it.
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?