Author: Ethan Heilman 2019-08-02 12:19:03
Published on: 2019-08-02T12:19:03+00:00
The author proposes the addition of a "moving checkpoint" to the Bitcoin protocol, which is a simple rule already implemented in NXT coin. Under this rule, a node will ignore any new block under nodeBlockHeight - N, making blockchain truly immutable after N blocks, even during a 51% attack. The author presents two attack scenarios and argues that a moving-checkpoint rule as described would make Bitcoin more vulnerable to 51% attacks. To make the rule safer, the author suggests that if a node detects a fork with both sides of the split having length > 144 blocks, it halts and requests user intervention to determine which chain to follow. The author notes that NXT has a fundamentally different security model as it uses Proof-of-stake rather than Proof-of-Work. Lastly, the author suggests that the security of the rule could be further improved by making the number of blocks a fork most reach to halt the network proportional to the difference in time between the timestamp in the block prior to the fork and the current time. However, the author clarifies that they are not proposing Bitcoin should adopt such a rule.
Updated on: 2023-06-13T20:40:07.083125+00:00