Joe Z.
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 Dec21 awarded Yearling Dec6 comment A proof-of-work random number generation system for Pokémon The paper is here, by the way: joezeng.com/papers/pokegen.pdf Mar28 comment Why are RSA key sizes almost always a power of two? "But the difficulty of computing the RSA public and private functions grows largely stepwise as n increases (more on why later)." Exponentiation by squaring, right? Feb19 comment Are asymptotic lower bounds relevant to cryptography? Now, to define h(y) without using the key x at all would theoretically turn it into a one-way function; doing so is a field known as "white-box cryptography". However, in the traditional one-time pad, h(y) requires the key x to define. Feb19 comment Are asymptotic lower bounds relevant to cryptography? Ah, but that's where we differ in what we are talking about. The key, along with the encryption "function", creates another "function" specific to that key. If you're familiar with currying, the one-time-pad f(x, y) can be curried into g(x), which takes the key x and returns the "function" h(y) that I was referring to, that takes the plaintext y and turns it into ciphertext z. 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 awarded Critic 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. Jan25 awarded Teacher Jan24 answered What is the most secure way to let Alice “input” her private key, transfer it to the server and decrypt the message? Jan24 accepted Why does Rijndael with a 256-bit block require the bottom two rows to be shifted one more space than usual? Jan24 revised Why does Rijndael with a 256-bit block require the bottom two rows to be shifted one more space than usual? A small grammatical nitpick. Those things bother me. Jan24 revised Why does Rijndael with a 256-bit block require the bottom two rows to be shifted one more space than usual? Going to re-tag it as well. Jan24 asked Why does Rijndael with a 256-bit block require the bottom two rows to be shifted one more space than usual? 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 revised Does it take brute force to find a pair of plaintext and ciphertext that each follow a certain condition, given an AES encryption key? Apparently this is what I really meant.