> From: Mark Woodward [mailto:[email protected]] > Sent: Monday, April 25, 2011 9:23 AM > > This is one of those things that make my brain hurt. If I am > representing more data with a fixed size number, i.e. a 4K block vs a > 16K block, that does, in fact, increase the probability of collision 4X,
Nope. Remember ... If you calculate 256-bit ideally distributed hashes of any two different input streams that are both 256-bits or larger, then the probability of collision is 2^-256 regardless of each input block size. When you create a 256-bit hash of any input >= 256 bits, you are essentially picking a random (but repeatable) number from 0 to 2^256-1. So the probability of collision is only dependent on the number of repetitions, and not dependent on the size of the input block. _______________________________________________ Discuss mailing list [email protected] http://lists.blu.org/mailman/listinfo/discuss
