.NET Security and Cryptography

Hash Algorithms

As we shall see, cryptographic hash functions are used in digital signatures, since they can be efficiently used for detecting message tampering. A hash is a function that maps an arbitrary-length binary data input to a small, fixed-length binary data output, often referred to as a message digest or finger print.

Good Hash Function Characteristics

A good hash function should have the property that it is a very low probability that two distinct inputs collide, producing the same hash value result. This allows the smaller, more manageable hash to be used effectively to represent or identify the larger data object. This is analogous to using a human fingerprint, which is a small and manageable, yet highly characteristic piece of ...