Replay attacks make BIP148 and BIP149 untennable



Summary:

In an email thread on the bitcoin-dev mailing list, Tao Effect suggested that mixing with 148 coinbase transactions destroys fungibility. However, CoinJoin could work as a method of improving fungibility and mixing with coinbase transactions. If someone wants to split a coin, they don't need to do anything clever; they can simply send a transaction with a standard fee that will confirm in a normal time on the higher hashrate chain but not as quickly on the lower hashrate chain. This is because transactions are valid on both chains, but blocks are found more slowly on the lower hashrate chain. Once the transaction is confirmed on one chain but not on the other, the user can "double-spend" on the lower hashrate chain with a higher fee, which will result in different coins on both chains.


Updated on: 2023-05-20T02:57:45.327224+00:00