Hashes and collisions

Posted Feb 16, 2004 14:37 UTC (Mon) by Omnifarious (guest, #19508)
In reply to: Hashes and collisions by nowster
Parent article: An attempt to backdoor the kernel

The birthday paradox, applied to SHA-1, means that you must have approximately 1/2**75 separately hashed entities before you start seeing a significant chance of collision.

This is still pretty tiny. So, in theory, hash by value should actually be pretty good. The paper is making the point that, while hash functions are designed to have certain properties, there is no guarantee that they do, and any lapse is catastrophic for algorithms that rely on them that heavily.