Published on: 2018-09-06T17:35:24+00:00
Ruben Somsen, in a recent post on the bitcoin-dev mailing list, discussed the idea of guiding transaction fees towards a more censorship-resistant outcome. He noted that when a user creates a transaction with a fee attached, they are incentivizing miners to add this transaction to the blockchain. The task is usually not very specific -- as long as it ends up in a valid chain with the most Proof-of-Work, miners get paid.However, transactions from Bitcoin Core are slightly more specific about what they ask miners to do. Every transaction is only valid at a block height that is one higher than the last block. BIP 115 by Luke-jr is even more specific and enables users to create transactions that are only valid if they are mined on top of a specific block. Coinjoin, which combines payments of multiple users into a single transaction, can be seen as yet another method for users to be more specific.This brings us to a theoretical scenario where every block contains only a single coinjoin transaction, the validity of which depends on the inclusion of a specific previous block, and the block reward is negligible compared to transaction fees. In this scenario, if miners wish to undo a specific transaction that happened two blocks ago, they would have to create three empty blocks (receiving negligible compensation) in order to overtake the longest chain. While not easy to achieve in practice (e.g. resolving natural forks becomes more complicated), it demonstrates that users can become more empowered than they are today, benefitting censorship resistance.Ruben suggested that such line of thinking may inspire further ideas in this direction. He also pointed out that fee pressure towards censorship resistance happens naturally if the system provides anonymity. If the target transaction that miners wish to censor is indistinguishable from other anonymous transactions, then miners will have no choice but to censor every anonymous transaction, so the end result is very similar to what he imagined linking transactions would do.
Updated on: 2023-08-01T23:52:24.726261+00:00