That’s true, but my wider point is that MTP isn’t a valid PoW timestamp as some scripts may assume. Peter Todd informed me that he was aware of MTP not being good for timestamps back in 2016 and Opentimestamps therefore doesn’t depend on it.
I opened a separate discussion about Timewarp attack 600 second grace period
Hi, i’d like to update this thread with the outcome of the discussions in the private one on the topic of improving the worst case validation time.
Shortly after posting the details of the worst block, i realized i could adapt it to be valid under the mitigations originally proposed in 2019. From there we reconsidered possible mitigations and their tradeoffs in terms of impact, confiscatory surface and complexity. Thanks to everyone who participated and in particular to Anthony Towns for his contributions, corrections and the helpful discussions.
After studying the various options i believe the best way forward is to introduce a 2’500 per-transaction limit on the number of legacy (both bare and P2SH) input sigops. This provides a 40x decrease in the worst case validation time with a straightforward and flexible rule minimizing the confiscatory surface. A further 7x decrease is possible by combining it with another rule, which is in my opinion not worth the additional confiscatory surface.
1 Like