Cryptographic Hash Function

Cryptographic hash functions are most commonly used for digital signatures and integrity checks such as proving authentication on security applications. The output it produces is a stream of data that represents the contents, often referred to as a hash value, message digest or a checksum. The transformation is a representation of the more complex data or longer message from which it was computed. A CRC (cycle redundancy check) is rather distinct from a cryptographic hash function. When used for security, a CRC is more vulnerable to attack. In various applications and protocols, the most widely used cryptographic hash functions are SHA-1 and MD5. Security defects were found in both of these algorithms in 2005. This led to the development of a new algorithm by the name of SHA-3 in 2007. A working analogy of a cryptographic hash function would be a tamper-proof sealed place on a software CD.