Bitcoin Optech: Newsletter #274 Recap

Mark “Murch” Erhardt and Mike Schmidt are joined by Bastien Teinturier, Fabian Jahr, Ethan Heilman, and Armin Sabouri to discuss Newsletter #274.

News

• Replacement cycling vulnerability against HTLCs (1:40)


• Bitcoin UTXO set summary hash replacement (24:21)


• Research into generic covenants with minimal Script language changes (40:02)


• Proposed BIP for OP_CAT (45:38)

Selected Q&A from Bitcoin Stack Exchange

• How does the Branch and Bound coin selection algorithm work? (52:17)


• Why is each transaction broadcast twice in the Bitcoin network? (54:29)


• Why are OP_MUL and OP_DIV disabled in Bitcoin? (56:57)


• Why are hashSequence and hashPrevouts computed separately? (58:56)


• Why does Miniscript add an extra size check for hash preimage comparisons? (59:52)


• How can the next block fee be less than the mempool purging fee rate? (1:00:51)

Releases and release candidates

• Bitcoin Core 25.1 (1:12:00)


• Bitcoin Core 24.2 (1:12:00)


• Bitcoin Core 26.0rc1 (1:14:23)