Hashing is the process of mapping large amount of data item to smaller table with the help of hashing function(A fixed process converts a key to a hash key is known as a hash function).Hashing is also known as Hashing algorithm or message digest function.It is a technique to convert a range of key values into a range of indexes of an array.It is used to facilitate the next level searching method when compared with the linear or binary search.Hashing allows to update and retrieve any data entry in a constant time O(1).Constant time O(1) means the operation does not depend on the size of the data.Hasing is used with database to enable items to be retrieved more quickly.It is used in the encryption and decryption of digital signatures.