ABSTRACT
A hash algorithm is a one-way mathematical function that is used to compress a large block of data into a smaller, fixed-size representation of that data. To understand the concept of hash functions, it is helpful to review some underlying mathematical structures. One such structure is called a function. The input into a hash algorithm can be of variable length, but the output is usually of fixed length and somewhat shorter in length than the original message. The output of a hash function is called a message digest. Applications such as user authentication and financial transactions are made more trustworthy by the use of hash algorithms. Secure hash algorithms are designed so that any change to a message will have a high probability of resulting in a different message digest. As such, the message alteration can be detected by comparing hash results before and after hashing.
