Introduction - If you have any usage issues, please Google them yourself
SHA (Secure Hash Algorithm, translated as Secure Hash Algorithm) is the design of the U.S. National Security Agency (NSA), the U.S. National Institute of Standards and Technology (NIST) released a series of cryptographic hash function. The official name for a member of the SHA family, was released in 1993. However, people now give it an informal name of SHA-0 to avoid confusion with its successor. Two years later, SHA-1, the first SHA successor release. In addition there are four variants, once released in order to enhance the range of the output and change some subtle design: SHA-224, SHA-256, SHA-384 and SHA-512 (these are sometimes called SHA-2).