Cryptographic hash function

From Wikipedia, the free encyclopedia

In cryptography, a cryptographic hash function is a transformation that takes an input and returns a fixed-size string, which is called the hash value. Hash functions with this property are used for a variety of computational purposes, including cryptography. The hash value is a concise representation of the message or document from which it was computed. Cryptographic hash functions are used to do message integrity checks and digital signatures in various information security applications, such as authentication and message integrity.

A hash function takes a string (or 'message') of any length as input and produces a fixed length string as output, sometimes termed a message digest or a digital fingerprint. A hash value (also called a "digest" or a "checksum") is a kind of "signature" for a stream of data that represents the contents. One analogy that explains the role of the hash function would be the "tamper-evident" seals used on a software package.

In various standards and applications, the two most commonly used hash functions are MD5 and SHA-1. In 2005, security flaws were identified in both algorithms. In 2007 the National Institute of Standards and Technology announced a contest to design a hash function which will be given the name SHA-3 and be the subject of a FIPS standard.

Change log:

2011-10-12 12:29 +1000: Fixed whitespace stripping, added some ajax form submission magic

2009-06-10 21:27 +1000: Added the final content for crc and haval - once more, borrowed and credited to Wikipedia

2008-09-30 07:14 +1000: Someone donated to me a better stylesheet and some images, so I installed them - it's amazing how much better someone with a little design skill can make things look.

2008-08-19 07:22 +1000: Added content for gost and adler32 - *insert usual Wikipedia comment here*

2008-08-15 12:28 +1000: Added content for sha, whirlpool, tiger and snefru - I hope Wikipedia doesn't mind me borrowing their content...

2008-08-11 07:19 +1000: More content was added for md4, md5, and ripemd - again, borrowing from Wikipedia.

2008-08-09 13:32 +1000: Added some content to Home and md2, blatently borrowed from Wikipedia.

2008-08-08 12:54 +1000: Replaced text box with textarea, imposed limit of 10,000 characters

2008-08-07 22:44 +1000: I got bored, and created this. Play around have fun.

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