I’ve been reading about digital signatures getting ready for some certification, and there is one question regarding this topic, that I don’t really understand.
Let’s say that I receive a plaintext with digital signature. I use the public key of the sender to decrypt. Now I have a “pure” hash. In order to check if it’s coming from a legitimate person, I need to hash the plaintext on my own.
But how do I know, which hashing algorithm has been used? Do I check the number of bits of the hashed function or something else?