3 ms·
Does this not set things up for a hash collision? They do exist, after all... if this scales to global proportions using SHA256 without verification for dedupli
by dedward 14y ago
Does this not set things up for a hash collision? They do exist, after all... if this scales to global proportions using SHA256 without verification for deduplication (if I read this correctly) is a risk.
- ewillbefull 14y ago256 bit collisions are too improbable. The distributed hash table that BitTorrent uses relies on a 160 bit keyspace (SHA1) and that is seen as sufficient.
- wcoenen 14y agoAssuming that there are no weaknesses in SHA256, you'd have to calculate a set of 4.8x10^35 hashes to have a one in a million chance of seeing at least one collision in that set[1]. If you could calculate (and store!) a trillion trillion (10^24) hashes per second, that would take about 15000 years. Needless to say, nobody has ever found a SHA256 collision. [1] http://en.wikipedia.org/wiki/Birthday_attack http://en.wikipedia.org/wiki/Birthday_attack
- bascule 14y agoThere are 115792089237316195423570985008687907853269984665640564039457584007913129639936 possible SHA256 hashes, which is a few orders of magnitude away from the number of atoms in the observable universe. The chances of an accidental hash collision are vanishingly small.
- deleted 14y ago[deleted]