Re:Speed Hashing
by derefr on Friday April 06, 2012 @01:13PM
(#3807990)
> Well, I'd say a hash that has no need whatsoever to be tamper-proof (no attackers, ever) and cares only about speed is a checksum -- so maybe a terminology issue.
Imagine someone trying to attack a BitTorrent tracker by injecting false data packets with "true" hashes. This is a case where you do want the properties of a hash, not a checksum (changing a single bit greatly changes the output; it's hard to figure out an input that will create a matching output) but you don't want the properties of a cryptographically-secure hash (slow to calculate.)
Imagine someone trying to attack a BitTorrent tracker by injecting false data packets with "true" hashes. This is a case where you do want the properties of a hash, not a checksum (changing a single bit greatly changes the output; it's hard to figure out an input that will create a matching output) but you don't want the properties of a cryptographically-secure hash (slow to calculate.)