what is a hash
a hash function is any function that can be used to map data of arbitrary size to data of fixed size the values returned by a hash function are called hash values hash codes hash sums or simply hashes one use is a data structure called a hash table widely used in computer software for rapid data lookuphash functions accelerate table or database lookup by detecting duplicated records in a large filehe values returned by a hash function are called hash values hash codes hash sums or simply hashes one use is a data structure called a hash table widely used in computer software for rapid data lookup hash functions accelerate table or database lookup by detecting duplicated records in a large file