Author: Eric Voskuil 2016-11-17 11:22:03
Published on: 2016-11-17T11:22:03+00:00
The discussion started with the possibility of future transactions having different txids. Eric Voskuil pointed out that this does not guarantee a no collision situation, but only makes it less likely to happen. He compared the scenario to excluding car accidents from consideration and then saying they are impossible. Tier Nolan suggested adding qualifiers to claims that rely on hash collisions instead of assuming that they aren't possible. The security of Bitcoin is not based on the assumption that hash collisions are impossible, but instead, block hash duplicates within the same chain are invalid as a matter of consensus. Furthermore, Tx hash collisions are permitted if the preceding transaction with the same hash is unspent. Compact blocks also consider hash collisions. Checkpoints are not part of Bitcoin security, so even if two different potential blocks have the same hash at the same height in the same chain, it does not indicate a problem. In conclusion, there is no case where the security of Bitcoin assumes that hashes never collide. Consensus rules have specific handling for both block hash collisions and tx hash collisions.
Updated on: 2023-06-11T20:36:20.256818+00:00