What you describe is an instance of the Hashcash Proof-of-Work. There are many other types of PoW, which don't amount to just computing a hash function [1]. [1

What you describe is an instance of the Hashcash Proof-of-Work. There are many other types of PoW, which don't amount to just computing a hash function [1]. [1] https://cryptorials.io/beyond-hashcash-proof-work-theres-mining-hashing https://cryptorials.io/beyond-hashcash-proof-work-theres-min...