On May 28, 2013, at 4:10 PM, Jens Alfke wrote: > CRC is primarily a checksum, not a hash function. It's good for verifying > data integrity, e.g. in a network protocol or file format, but more expensive > than you’d like for a hash table. There are much faster hash functions: > Wikipedia has a good list[1].
http://en.wikipedia.org/wiki/Hash_function Hashing with cryptographic hash functions [edit] Some cryptographic hash functions, such as SHA-1, have even stronger uniformity guarantees than checksums or fingerprints, and thus can provide very good general-purpose hashing functions. In ordinary applications, this advantage may be too small to offset their much higher cost.[5] However, this method can provide uniformly distributed hashes even when the keys are chosen by a malicious agent. This feature may help to protect services against denial of service attacks. I thought I saw SHA-1 being used as a general purpose hash function somewhere sort of surprising recently but I'm not remembering exactly where. Maybe if the collision resistance or hash value uniformity out weigh the performance concerns? Michael Hall trz nio.2 for OS X http://www195.pair.com/mik3hall/index.html#trz HalfPipe Java 6/7 shell app http://www195.pair.com/mik3hall/index.html#halfpipe AppConverter convert Apple jvm to openjdk apps http://www195.pair.com/mik3hall/index.html#appconverter _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
