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Re:Speed Hashing by haberman on Friday April 06, 2012 @03:05PM (#3808441)
Correct me if I'm wrong, but my understanding is that cryptographic and non-cryptographic hash functions have similar avalanche properties (and therefore similar probability of accidental collision); the difference is just that cryptographic hash functions make it difficult to intentionally create a collision.

Is that right?

Re:Speed Hashing by cperciva on Friday April 06, 2012 @04:43PM (#3808841)
Good non-cryptographic hash functions have "good" avalanching behaviour, but the definition of "good" depends on how randomly you expect your inputs to behave and how much a collision costs you. In hash tables, for instance, people often use quite weak -- i.e., poorly avalanching -- hashes since the cost of a collision is quite low.

Probably the best way to phrase it is that non-cryptographic hash functions cover a continuum with checksums at one extreme and cryptographic hash functions at the opposite extreme.