mikeazo
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 Apr 24 comment How to securely map an element from an smaller domain to the other element in a large domain If the technique is public, what stops the adversary from running it herself?Typically the answer to that is a secret key, but you don't want to use secret keys. So, maybe there is no solution? Apr 24 revised How to securely map an element from an smaller domain to the other element in a large domain edited title Apr 24 revised Prime factorization added 25 characters in body Apr 24 comment Prime factorization Sounds like we have at least a few good answers here in the comments. Anyone care to write theirs up? Apr 23 revised Common Modulus Attack in RSA added 4 characters in body Apr 23 answered Common Modulus Attack in RSA Apr 23 revised Common Modulus Attack in RSA added 2 characters in body Apr 23 comment Why does second pre-image resistance imply pre-image resistance I don't really agree with this answer, because to me, the identity function is not a hash function. Look at the definitions of hash function and cryptographic hash function on Wikipedia. I see problems with the identity function with relation to both of those definitions. Apr 23 comment Why does second pre-image resistance imply pre-image resistance I don't think what @scampos has done necessarily deserves a deletion. See this question on meta.SE. We have also discussed this sort of thing on our Meta. At the very least, the answer expands slightly (add some mathematical notation, etc) to Ricky's comment. Apr 23 comment Is the reverse of the “discrete logarithm problem” equally dificult? I linked to a question dealing with composite modulus, here is one dealing with prime modulus. Apr 23 comment Is the reverse of the “discrete logarithm problem” equally dificult? The op had a comment (now deleted) suggesting modulo a prime. Apr 23 comment Is the reverse of the “discrete logarithm problem” equally dificult? For $k=2$ you use Tonelli-Shanks. Apr 23 revised Is the reverse of the “discrete logarithm problem” equally dificult? added 16 characters in body Apr 23 comment Is the reverse of the “discrete logarithm problem” equally dificult? Typically dlog is defined in a group mod p, but it doesn't have to be. I think that other question contains your answer, though not explicitly, so I'd leave this one open. It says "Yes, the problem of finding... is believed hard unless the factorization of $N$ can be determined". Well, you know the factorization of $p$, it is $p$ :) Apr 23 comment Is the reverse of the “discrete logarithm problem” equally dificult? Here is a related question that deals with computing roots when the modulus is composite. Apr 22 revised Multiple AES/ECB encryptions of different data with same key all end with same pattern rolled back to a previous revision Apr 22 revised Multiple AES/ECB encryptions of different data with same key all end with same pattern rolled back to a previous revision Apr 22 comment Can Grover's algorithm be parallelized? It doesn't directly answer the question as you are not talking about doing p queries in parallel, but 1 query parallelized. Apr 22 comment Can Grover's algorithm be parallelized? I didn't dive deep enough to tell if this paper answers the question (Optimal Parallel Quantum Query Algorithms), but I found this interesting quote: "Suppose one wants to search an n-bit database, with the ability to do p queries in parallel in one time-step. An easy way to make use of this parallelism is to view the database as p databases of n/p bits each, and to run a separate copy of Grover’s algorithm on each of those." Apr 22 comment Key distribution and computation for homomorphic encryption @1010101 don't forget, if you find this answer helpful you can up vote it and even accept it (click on the check).