Reference Work Entry

Encyclopedia of Cryptography and Security

pp 1190-1193

SHA-0, SHA-1, SHA-2 (Secure Hash Algorithm)

  • Helena HandschuhAffiliated withComputer Security and Industrial Cryptography Research Group, Katholieke Universiteit Leuven


Secure hash algorithm; SHA

Related Concepts

Hash Functions; Message Digest; SHA-3 Competition


The SHA (Secure Hash Algorithm) Family currently designates a family of six different hash functions: SHA-0, SHA-1, SHA-224, SHA-256, SHA-384, and SHA-512 [910] published by the American National Institute of Standards and Technology (NIST). They take variable length input messages and hash them to fixed-length outputs.


Hash functions are functions which take a variable input message and compute a fixed-length message digest for each such message. This digest serves as a digital fingerprint allowing a receiver to check that the original message has not been altered during transmission. Hash functions are unkeyed cryptographic primitives which do not guarantee authenticity. They can be combined with a secret key to produce a message authentication code. They also serve as a cryptographic primitive used in digital signature s ...

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