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Secure Hash Algorithms | |
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Concepts | |
hash functions, SHA, DSA | |
Main standards | |
SHA-0, SHA-1, SHA-2, SHA-3 | |
A cryptographic hash function (CHF) is a hash algorithm (a map of an arbitrary binary string to a binary string with a fixed size of bits) that has special properties desirable for a cryptographic application:[1]
Cryptographic hash functions have many information-security applications, notably in digital signatures, message authentication codes (MACs), and other forms of authentication. They can also be used as ordinary hash functions, to index data in hash tables, for fingerprinting, to detect duplicate data or uniquely identify files, and as checksums to detect accidental data corruption. Indeed, in information-security contexts, cryptographic hash values are sometimes called (digital) fingerprints, checksums, or just hash values, even though all these terms stand for more general functions with rather different properties and purposes.[2]
Non-cryptographic hash functions are used in hash tables and to detect accidental errors; their constructions frequently provide no resistance to a deliberate attack. For example, a denial-of-service attack on hash tables is possible if the collisions are easy to find, as in the case of linear cyclic redundancy check (CRC) functions.[3]
Much more than encryption algorithms, one-way hash functions are the workhorses of modern cryptography.