| one-way hash function (Or "message digest function") A function which takes a variable-length message and produces a fixed-length hash. Given the hash it is computationally impossible to find a message with that hash; in fact one can't determine any usable information about a message with that hash, not even a single bit. For some one-way hash functions it's also computationally impossible to determine two messages which produce the same hash. A one-way hash function can be private or public, just like an function. and are examples of public one-way hash functions. A public one-way hash function can be used to speed up a public-key system. Rather than sign a long message which can take a long time, compute the one-way hash of the message, and sign the hash. {sci.crypt FAQ (ftp://src.doc.ic.ac.uk/usenet/usenet-by-group/sci.crypt/)}. (1995-02-16) |
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