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1d
comment Stateless hash based public key cryptography?
@HenrickHellström, the blog post (the first URL) has some more details. We save only the first level -- that's generated during key generation and treated as part of the private key. We regenerate the subtrees on the fly as needed. How are they generated? They can be generated via a GGM construction from a seed (e.g., computed as a PRF of some master key that's part of the private key, plus an identifier that identifies which subtree we're looking at). There's no need to save the subtrees, since they can be generated deterministically on demand as needed. Does that answer your questions?
1d
answered Stateless hash based public key cryptography?
Apr
20
answered MAC security and adversaries with memory
Apr
18
comment Client-server authentication protocol suggestion
Also, this question would be a better fit for Security.SE, as it is more a question about protecting a deployed system than about the crypto.
Apr
18
comment Client-server authentication protocol suggestion
"I know that I could just use SSL, but I would like to (for some reasons)" - What does that mean? Did you leave out some words? What would you like to? And what are the reasons? The first question a security professional is probably going to ask is: why not just use SSL? I encourage you to edit the question to make this clearer, if you'd like to get useful responses.
Apr
17
comment Is it possible to forge elgamal in a determinsic way?
El Gamal signatures are not forgeable, when properly used.
Apr
17
comment Is the strength of RSA over quadratic or other cyclotomic fields as strong as over the integers?
Can you explain what you mean by "compose the modulus of some other quadratic ring"? Do you mean that instead of multiplying two integers to get the modulus, we multiply two elements of some quadratic ring? Have you worked out what the corresponding version of Euler's lemma is? What is the order of the multiplicative group of such rings? What's the motivation for your question? Are you hoping to get a cryptosystem that will be faster than RSA, for a given security level?
Apr
16
comment Are there any elliptic curve asymmetric encryption algorithms?
Thanks, DrLecter! Makes sense! On re-reading the question, the question is not as clear as I initially thought. The question says "Is there an algorithm which employs elliptic curve cryptography, fast asymmetric encryption, [...]" - I took that to mean it wants the encryption operation to be fast, like in RSA, but it's entirely possible that might not be the right reading. Perhaps the original author will take a moment to edit the question and make what he/she is looking for clearer.
Apr
16
comment Are there any elliptic curve asymmetric encryption algorithms?
Those are all good schemes, but doesn't the question ask for encryption to be fast like in RSA? Do any of these schemes support encryption that is as fast as RSA's encryption? As far as I can tell, none of them are -- have I misunderstood? I think there's a tradeoff: RSA encryption will be faster than the ECC schemes; the ECC schemes will be faster for everything else, and will have shorter keys.
Apr
16
comment What happens if biometric data is stolen?
In addition, we expect people to do serious research on their own before asking, and to show us what they've done. There's a lot that has been written on this subject; you should try doing some searching on this topic before asking. For instance, have you tried Bruce Schneier's blog and books? Have you read through Wikipedia? Have you read standard introductions to biometrics, e.g., in Ross Anderson's Security Engineering book?
Apr
15
revised Are AES-256's related-key weaknesses exploitable if it is used to build a hash?
added 139 characters in body
Apr
14
comment In Pedersen Key Distribution, can the public key be persistent?
Are you saying there is an attack if you re-use $(p,g,h)$ too many times? Are you saying that existing proofs don't make any promises if you re-use $(p,g,h)$ too many times? Can you give some intuition for what the nature of the alleged trouble is? I find it hard to believe that there is a real problem. It is bog-standard to re-use the public key $(p,g,h)$ in discrete-log-based cryptosystems; is there any reason that Pederson would be different?
Apr
14
answered Are AES-256's related-key weaknesses exploitable if it is used to build a hash?
Apr
13
reviewed Edit suggested edit on knapsack tag wiki
Apr
13
revised knapsack wiki description
deleted 151 characters in body
Apr
13
reviewed Reject suggested edit on knapsack tag wiki excerpt
Apr
11
answered How do I express each element in a field F as a power of a primitive element?
Apr
7
comment How could Fully Homomorphic Encryption support power operations?
My perspective: The answer says that XOR and AND are universal, and thus any operation, including addition and multiplication, can be built out of XOR and AND gates. That is a correct statement. So the answer seems fine to me. But we can agree to disagree (or have a slightly different reaction) -- nothing wrong with that!
Apr
7
comment How could Fully Homomorphic Encryption support power operations?
@poncho, I don't understand your comment. This answer looks correct to me. The answer never says "ADD==XOR", does it? XOR and AND are universal; no need for NAND.
Apr
7
comment How could Fully Homomorphic Encryption support power operations?
You already answered your own question. "It enables arbitrary functions..." Power is a function.