Author: darosior 2022-02-19 17:20:19
Published on: 2022-02-19T17:20:19+00:00
In a recent discussion on the Lightning-dev mailing list, Peter Todd and Jeremy Rubin debated the use of the term "pinning" in relation to a new type of attack on Bitcoin transactions. Todd argued that using the term "computation" in reference to blockchain transactions is misleading, while Rubin suggested that "necromancing" might be a more fitting term for the new attack. Todd agreed that this name could work for an attack that involves getting an out-of-date version of a transaction mined. The specific use case discussed was OpenTimestamps calendars, which use RBF (replace-by-fee) to update timestamp transactions with a new merkle tip hash once per block. In high fee situations, there can be dozens of versions of the same transaction, each with a slightly higher feerate. Older versions getting mined wastes money and delays settlement, causing issues beyond just the OTS use case. While some entities use "in-place" replacement for updating low-time-preference settlement transactions by adding new txouts and updating existing ones, older versions getting mined rather than newer versions wastes money and delays settlement for the same reason it does in OTS. Todd suggests that if fee accounts or any similar mechanism get implemented, they should be opt-in. Rubin suggested that third-party attackers could mess up OTS calendars by delaying the mining of timestamp transactions. Todd noted that there is no chain of unconfirmed transactions, and that OTS calendars can handle any versions of the same transaction being mined. However, older versions getting mined still wastes money and delays settlement. Rubin also mentioned that attackers could already perform similar attacks using out-of-band transaction fees, but Todd pointed out that such services are either scams or very expensive. Todd's final point was that getting "necromanced" on an earlier RBF'd transaction by a third party does not save you money in fees overall, contrary to what Rubin suggested.
Updated on: 2023-06-03T07:06:37.691429+00:00