Bitcoin Optech newsletter #423 is here: - summarizes an analysis of mining pool difficulty controllers stranding slowed miners - describes a proposed improvement to Utreexo’s initial block download - links to a draft BIP for specifying unspendable taproot internal keys - summarizes changes to services/client software - Optech Newsletter #423 Podcast

Rob Hamilton (@Rob1Ham), PortlandHODL (@PortlandHODL), Chandra Pratap, and fabohax (@fabohax) joined Optech to discuss Newsletter #416: Action items ● Move funds secured by COLDCARD-generated keys (1:07) News ● Wallets generated by COLDCARD at risk of theft (2:18) ● Disclosure of two DoS vulnerabilities in Core Lightning (36:26) ● Proof of concept for a zero-knowledge proof of reserves (49:54) Selected Q&A from Bitcoin Stack Exchange ● What is Bitcoin's objective definition of transaction neutrality? (1:03:07) ● Why does BIP110's decentralization benefit not outweigh its impact on transaction neutrality? (1:05:17) ● Why does BIP110 require a 55% signaling threshold if its nodes reject non-signaling blocks? (1:09:46) ● Why use ElligatorSwift encoding in BIP324? (1:17:12) ● Was the OP_SUCCESSx reservation in BIP342 designed with specific opcode families in mind? (1:25:36) ● What is the difference between the long-term feerate and the discard feerate? (1:29:14) ● What is the quickest method for migrating a legacy wallet to a descriptor wallet on a pruned node? (1:32:40) ● Is there historical data on orphan/stale block rates during high-fee periods? (1:36:09) Releases and release candidates ● BTCPay Server 2.4.1 (1:41:25) ● Eclair 0.14.1 (1:42:14) Notable code and documentation changes ● Bitcoin Core #34628 (1:44:26) ● Bitcoin Core #28463 (1:49:49) ● Bitcoin Core #32800 (1:54:18) ● Bitcoin Core #34683 (1:56:54) ● Bitcoin Core #33014 (1:58:09) ● Eclair #3325 (1:59:31) ● BOLTs #1346 (2:00:57) ● BOLTs #1344 (2:02:10) ● BOLTs #1343 (2:04:14)

Liam Eagen joined Optech to discuss Newsletter #390: News ● Argo: a garbled-circuits scheme with more efficient off-chain computation (0:48) ● LN-Symmetry update (26:05) Selected Q&A from Bitcoin Stack Exchange ● What is stored in dbcache and with what priority? (34:21) ● Can one do a coinjoin in Shielded CSV? (24:02) ● In Bitcoin Core, how to use Tor for broadcasting new transactions only? (36:47) ● Brassard-Høyer-Tapp (BHT) algorithm and Bitcoin (BIP360) (38:31) ● Why does BitHash alternate sha256 and ripmed160? (39:24) Releases and release candidates ● Libsecp256k1 0.7.1 (41:09) Notable code and documentation changes ● Bitcoin Core #33822 (42:59) ● Bitcoin Core #34269 (44:50) ● Core Lightning #8850 (47:38) ● LDK #4349 (49:16) ● Rust Bitcoin #5470 (50:54) ● Rust Bitcoin #5443 (51:26) ● BDK #2037 (52:51) ● BIPs #2076 (55:49) ● BIPs #1500 (59:39)

Anthony Towns (@ajtowns) and Mikhail Kudinov (@kudinov_mikhail) joined Optech to discuss Newsletter #386. A notice about the wallet migration bug in Bitcoin Core was discussed at (56:30) News ● Building a vault using blinded co-signers (1:04:09) ● Peer feature negotiation (1:40) Changing consensus ● Year 2106 timestamp overflow uint64 migration (1:07:47) ● Relax BIP54 timestamp restriction for 2106 soft fork (1:11:36) ● Understanding and mitigating a CTV footgun (1:16:30) ● CTV activation meeting (1:21:00) ● `OP_CHECKCONSOLIDATION` to enable cheaper consolidations (1:23:11) ● Hash-based signatures for Bitcoin's post-quantum future (20:47) Releases and release candidates ● BTCPay Server 2.3.0 (1:28:29) Notable code and documentation changes ● Bitcoin Core #33657 (1:30:25) ● Bitcoin Core #32414 (1:33:23) ● Bitcoin Core #32545 (1:39:18) ● Bitcoin Core #33892 (1:42:13) ● Core Lightning #8784 (1:44:35) ● LND #9489 (1:45:54) ● BIPs #2051 (1:50:09) ● BOLTs #1299 (1:56:39) ● BOLTs #1305 (1:59:46)