How cryptography hash function work?

[CryptoForum]

Cryptographic hash functionis essentially a compression function. It takes as input data of arbitrary length and outputs a fixed-length hash value that can uniquely identify the data. A hash function is deterministic and the computation of the hash value of an input string x can be done in time bounded by a small-degree polynomial in the size of x.

[BenFormer]

It's too difficult for some crypto lovers to know that. But thanks for info. It's quite well written.