Joe Z.
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 Feb19 comment Are asymptotic lower bounds relevant to cryptography? @WilliamHird: In the case of the one time pad, you don't know the function that was used to encrypt the data. That's where all its security comes from. A one way function is one where you can know the function and it will still be hard to invert. Feb19 comment Are asymptotic lower bounds relevant to cryptography? @WilliamHird I think you are misunderstanding the nature of a one-way function. Any symmetric encryption algorithm (such as the one-time pad) using the same key to encrypt and decrypt is not a one-way function. A one-way encryption algorithm is a cipher that you cannot decrypt, even given all the information that was used to encrypt it (such as a public-key function). Feb1 comment Is (2^333)-1 a prime number? It's also divisible by $2^3 - 1 = 7$ by the same argument. i.e. It's not even close to prime. Jan27 comment Why can't one implement bcrypt in Cuda? For a moment I misread "Cuda" as "Cuba" and thought this was an encryption import problem. Jan26 comment Cryptographic Symmetric Stream Cipher Are S and P inverses of each other? What are you trying to do here? Jan26 comment Cryptographic Symmetric Stream Cipher We'd need to know more about these S() and P() functions in order to tell you how secure they are. Jan23 comment Does it take brute force to find a pair of plaintext and ciphertext that each follow a certain condition, given an AES encryption key? In the application I'm using it for, the block size is 256, and about 112 bits are fixed on each side. Jan22 comment Does it take brute force to find a pair of plaintext and ciphertext that each follow a certain condition, given an AES encryption key? So basically the "security assumption" is based around the number of operations required, in which case, supposing I used AES-256 with 128 bits on each side, it would be. It's not that I actually need it to be a security assumption; I was really just initially wondering whether there was a better way than brute force to find plain/cipher pairs. Jan22 comment Does it take brute force to find a pair of plaintext and ciphertext that each follow a certain condition, given an AES encryption key? Could I use it as a security assumption if I upped the bit specification to 64? Jan22 comment Does it take brute force to find a pair of plaintext and ciphertext that each follow a certain condition, given an AES encryption key? "Perhaps you were hoping there was some clever way to take advantage of the partly known plaintext/ciphertext; it doesn't work out." Actually, I was hoping there wasn't such a way and that somebody would verify the fact. :P Jan22 comment Does it take brute force to find a pair of plaintext and ciphertext that each follow a certain condition, given an AES encryption key? That's what I was looking for; thanks. I was wondering whether there was any method easier than those two you listed. If there aren't, that's perfect. Jan19 comment Is it safe to use RSA as a proof-of-work system? "However, I wanted to point out that there are other ways to build proof-of-work schemes other than using RSA. Some of them may be superior to RSA-based schemes." I know; I was just wondering whether that thing worked or not. Jan19 comment Is it safe to use RSA as a proof-of-work system? @D.W. This is a rather hypothetical question. Any public-key algorithm should work. Jan19 comment A proof-of-work random number generation system for Pokémon A colleague of mine at the University of Waterloo suggested this same system about a year ago. I presented him with the same concern, and he gave me the same response. Jan19 comment A proof-of-work random number generation system for Pokémon I think the issue with a fixed limit is that it will be literally impossible for certain players to roll "perfect" characters, and I don't want to make that literally impossible, just as unlikely as the game intended. Jan19 comment A proof-of-work random number generation system for Pokémon I've realized that in its current form, this question is very confusing, unclear, and unsuitable for this website. I'm currently writing a paper to formalize the system, which I will submit in a new question. Jan17 comment Are asymptotic lower bounds relevant to cryptography? The one-time pad has nothing to do with the P=NP problem. In fact, if you encrypt using a one-time pad, the unicity distance is the length of the text itself, and you can never even brute-force the result out, or even know if you have the right result without other information. Jan15 comment Why programming languages don't provide simple encryption methods? "Frameworks could include both the easy version as well as the sophisticated one." The problem there is that there isn't one single "sophisticated" crypto scheme that a library could include by default. There are, as David Schwartz said, varying needs for varying applications of cryptography. Jan6 comment A proof-of-work random number generation system for Pokémon [Hmm, so you can create a chatroom for an answer thread.] Jan6 comment A proof-of-work random number generation system for Pokémon