Great Consensus Cleanup (BIP-54)
A soft fork bundling fixes for the timewarp bug, slow-to-validate blocks, 64-byte transactions and duplicate coinbases; first drafted in 2019 and specified as BIP-54 in 2025.
On S17 E48 Robin Linus said Peter Todd guessed the Cleanup would come in 2029, and that if that was all Bitcoin got, “I'm out”.[3]
Proposal
BIP-54 names Antoine Poinsot and Matt Corallo as authors and proposes rules “to fix the timewarp attack, reduce the worst case block validation time, prevent Merkle tree weaknesses, and avoid duplicate transactions without” BIP-30 validation[1]. It says that in the worst case a timewarp attacker “can bring down the difficulty to its minimum within 38 days”[1].
History
Bitcoin Optech says the effort followed “a prior draft in 2019” that was deferred, with renewed work since 2023 that became BIP54[2]. Optech lists the four fixes as the time warp bug, slow-to-validate blocks, the Merkle tree weakness of 64-byte transactions, and the duplicate transaction vector[2]. The BIP's status is Complete[1]. Optech's 2026 entries include a summary of “the remaining steps before activation”, so it had not activated by then[2].
On the show
Robin Linus said on S17 E48 that Peter Todd had guessed “the Great Consensus Cleanup will come in, like, '29”[3]. In the same conversation he said “We're going to get BIP 448, TEMPLATEHASH”[4].
References
- primaryBIP-54, “Consensus Cleanup” (Antoine Poinsot, Matt Corallo) [archived]
- secondaryBitcoin Optech topic, “Consensus cleanup soft fork” (also covering BIP54) [archived]
- episodeS17 E48: Robin Linus on Peter Todd's guess of a 2029 Great Consensus Cleanup▶ listen at 39:14timestamp transcript-derived, pending a listen [archived]
- episodeS17 E48: Robin Linus — “We're going to get BIP 448, TEMPLATEHASH”▶ listen at 40:26timestamp transcript-derived, pending a listen [archived]