A hash function is a “random oracle” You give it an arbitrarily-sized input. … If so, it gives you those 256 random bits as output. If not, it flips 256 random coins, associates them to this input, and gives you the coins as output.

Is sha256 truly random?

The SHA-256 (as well as any cryptographically secure hash algorithm) produces output that will appear like an uniformly random sequence to observer who does not know the input.

Are all hash functions the same?

Hash functions differ by type; however, there are several characteristics that persist between them. Deterministic: The hash value remains the same. No matter how many times you input a message into the hashing function you need to receive the same output.