On: Hash Functions

[layer8]

I’m familiar with hash functions for signatures, however I’m confused about the mention for encryption, in particular with respect to the context of common schemes like AES and RSA. I guess hashing a key is an option though.

[commandersaki → layer8]

Modern hashing functions pretty much offer encryption out of box like gimli or BLAKE2 family (I think they call it XOF mode).

This is pretty much thanks to the sponge construction.

[tptacek → commandersaki]

You can spitball a hash-based stream cipher with any hash function in just a couple lines of python. Take a 128 bit key string, and then hash it with an incrementing counter to get successive 32 bytes of keystream data, just like you would with AES in CTR mode.