alt Hacker NewsI read and understood the article, including the math in it, then came here (I know, that’s the wrong order) and read your comment, and promptly decided I knew less than I did before I started. It was very much like learning to use a monad in Haskell without knowing category theory, and then reading an article about them. Just because you understand an article written for the educated general public doesn’t mean you have the vocabulary to understand experts speaking to other experts.
Yeah, I'm not vouching for the article, just saying my response to it was that the simpler explanation for cryptographic hash functions is that they're a specialized application of a block cipher core.
The job of a modern block cipher core is to take a (heavily) iterated function, figure out how to apply a single input key securely to each of those iterated rounds, thoroughly combining the key with the block of data, achieving indistinguishability from random as quickly into the sequence of rounds as possible (in the same kind of simple step process as a Rubik's Cube), while breaking structure (like linearity) that would solve for the key or the data mathematically.