Is there a difference between PRF and a hash function?

Question

Is there a difference between PRF and a hash function?

For example: Creation of a secret key is using PRF and creating a secret key is using hash function.

Answer 1

No, the two primitives are definitely not the same.

A pseudorandom function is a keyed function that is (computationally) indistinguishable from a function chosen at random from all functions with matching domain and range as long as the key remains secret.

On the other hand, a cryptographic hash function is a function with either a publicly known key (in theory) or no key at all (in practice) that is compressing and collision resistant. That means, it maps long inputs to outputs of a fixed length and it is hard to find two inputs that map to the same output.