![Search icon](https://hackernoon.imgix.net/search-new.png?w=19&h=19)
A cryptographic hash function, also sometimes called a digest function, is a cryptographic primitive transforming a message of arbitrary size into a message of fixed size, called a digest. Cryptographic hash functions are used for authentication, digital signatures, and message authentication codes.
To be used for cryptography, a hash function must have these qualities:
Cryptographic hash functions such as MD5 and SHA-1 are considered
broken, as attacks have been found that significantly reduce their
collision resistance.