Author: ZmnSCPxj 2020-02-08 02:15:32
Published on: 2020-02-08T02:15:32+00:00
A potential form of sabotage attack, named Purge attacks, that can be conducted by miners to create coordination disincentives among Bitcoin users has been discovered. The attack replaces the most recent blocks full of transactions with empty blocks, causing previously confirmed transactions to return into the mempool. This enables anyone with technical knowledge or access to public tools to opportunistically double-spend their transactions back to themselves. The attack is aimed at undermining trust in Bitcoin's assurances regarding the future finality of transactions and disrupting the coordination process among users in response to the attack. By giving some users a chance to benefit from the attack, the attacker gives them a vested interest in staying on the attack chain. Purge attacks do not constitute a bigger risk than other known forms of sabotage attacks but are an interesting spin where the attacker specifically targets the pre-coordination of defenders. A solution called "Uncontested Safe" has been proposed to eliminate transaction replacement that is consensus compatible but has limitations. Purge attacks can still be defended against without requiring mass cooperation if enough self-interested users offer substantial mining fees for the transactions being censored. Non-censoring miners can then be convinced to mine those transactions without any coordination, thus maintaining the censorship-resistance of Bitcoin.
Updated on: 2023-06-13T23:21:04.956100+00:00