Tag Info

New answers tagged

2

Paŭlo Ebermann has given a good answer from a strict cryptographic perspective, and David Cary has given many useful engineering considerations. I want to add, or maybe prefix, these answers with some more engineering considerations. The main problem is that bitwise operations in Lua (5.2 at least) are very slow and the implementation ComputerCraft can ...


3

Rather than LuaCrypto or some other Lua binding to some (blazing fast) low-level cryptographic library in some other language; I'm assuming that you want a "pure Lua" implementation. Would one of the following work for you? ARCFOUR in pure Lua (a) (b) (c) (d) Lua wiki: Cryptography (b) Pure LUA encryption (d) "Very simple string Encryption"(w) (k) yet ...


4

Your cipher is a synchronous stream cipher build on a random number generator. For cryptographically secure random number generators (CSRNG), this is a secure stream cipher. The problem is, that your random seed is way too small for any security. Trying all possible seeds and seeing if the decryption result makes some sense (assuming the plaintext makes ...


9

Their numbers are off and the explanation confusing, but they do have a point. The algorithms used for RDRAND/RDSEED instructions are described in the software implementation guide (pdf). What it amounts to is that for RDRAND, some hardware entropy is conditioned and used as a 256-bit seed for AES CTR_DRBG (from SP 800-90A). The same 256-bit seed is used ...


7

It would appear that, in this case, your intuition is correct, and the Intel guy is wrong. When you concatenate two random values, the entropy contained in the concatination depends not only one the entropy of those two sources, but whether they are correlated. If they are entirely uncorrelated, that is, if the probability distribution of one of the random ...


14

Even in context, much of what is written in the blog post makes no sense. E.g., it says: While it can be argued that the DRNG is in reality just splitting a 128-bit value into two pieces and handing them to you one piece at a time, from a theoretical viewpoint this does not matter. While the original value had 128 bits of entropy, the end result is that ...



Top 50 recent answers are included