Bitcoin Optech Podcast

Mark “Murch” Erhardt, Gustavo Flores Echaiz, and Mike Schmidt are joined by Toby Sharp, Chris Hyunhum Cho, Jonas Nick, and Antoine Poinsot to discuss ⁠Newsletter #391⁠.News● A constant-time parallelized UTXO database (25:40) ● Bithoven: A formally verified, imperative language for Bitcoin Script (44:48) ● Discussion of dust attack mitigations (1:43:33) Changing consensus● SHRINCS: 324-byte stateful post-quantum signatures with static backups (1:30) ● Addressing remaining points on BIP54 (1:10:08) ● Falcon post-quantum signature scheme proposal (20:05) ● SLH-DSA verification can compete with ECC (23:28) Releases and release candidates● LDK 0.1.9 (1:50:27) Notable code and documentation changes● Bitcoin Core #33604 (1:53:10) ● Bitcoin Core #34358 (1:54:58) ● Core Lightning #8824 (1:56:20) ● Eclair #3244 (1:58:17) ● LDK #4263 (2:00:07) ● LDK #4300 (2:01:54) ● LND #10473 (2:03:57) ● Rust Bitcoin #5493 (2:07:36)

Mark “Murch” Erhardt and Gustavo Flores Echaiz are joined by Liam Eagen 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)

Mark “Murch” Erhardt and Mike Schmidt are joined by René Pickhardt to discuss ⁠Newsletter #389⁠.News● A mathematical theory of payment channel networks (0:31) Changes to services and client software● Electrum server for testing silent payments (30:04) ● BDK WASM library (33:28) Releases and release candidates● Core Lightning 25.12.1 (35:14) ● LND 0.20.1-beta.rc1 (39:14) Notable code and documentation changes● Bitcoin Core #32471 (40:57) ● Bitcoin Core #34146 (42:02) ● Core Lightning #8831 (45:00) ● LDK #4261 (45:35) ● LDK #4152 (46:24) ● LND #10488 (47:42) ● LND #10331 (48:43) ● Rust Bitcoin #5402 (49:06) ● BIPs #1820 (50:39) ● BOLTs #1306 (51:41) ● BLIPs #59 (53:05)

Mark “Murch” Erhardt, Gustavo Flores Echaiz, and Mike Schmidt are joined by Bruno Garcia to discuss ⁠Newsletter #388⁠.News● An overview of incremental mutation testing in Bitcoin Core (0:43) ● BIP process updated (18:53) Releases and release candidates● Bitcoin Core 30.2 (26:31) ● BTCPay Server 2.3.3 (27:23) Notable code and documentation changes● Bitcoin Core #33819 (28:42) ● Bitcoin Core #29415 (31:44) ● Core Lightning #8830 (42:16) ● Eclair #3233 (44:19) ● Eclair #3237 (47:59) ● LDK #4232 (50:00) ● LND #10296 (52:24) ● BTCPay Server #7068 (53:43) ● BIPs #1982 (55:37)

Mark “Murch” Erhardt, Gustavo Flores Echaiz, and Mike Schmidt are joined by René Pickhardt and Craig Raw to discuss ⁠Newsletter #387⁠.News● Bitcoin Core wallet migration bug (0:55) ● Using Ark as a channel factory (7:47) ● Draft BIP for silent payment descriptors (29:02) Releases and release candidates● Bitcoin Core 30.2rc1 (58:34) Notable code and documentation changes● Bitcoin Core #34156 (59:32) ● Bitcoin Core #34085 (1:03:54) ● Bitcoin Core #34197 (1:07:43) ● Bitcoin Core #33135 (1:09:10) ● LDK #4213 (1:11:02) ● Eclair #3217 (1:15:39) ● LND #10367 (1:18:49) ● Rust Bitcoin #5450 (1:22:51) ● Rust Bitcoin #5434 (1:23:40)

Mark “Murch” Erhardt, Gustavo Flores Echaiz, and Mike Schmidt are joined by Anthony Towns and Mikhail Kudinov to discuss ⁠Newsletter #386⁠.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)

Mark “Murch” Erhardt and Mike Schmidt are joined by Bastien Teinturier, Rearden Code, and Pieter Wuille to discuss Newsletter #385: 2025 Year-in-Review Special.January● Updated ChillDKG draft (43:08) ● Offchain DLCs (45:53) ● Compact block reconstructions (2:29:27) February● Erlay update (1:53:55) ● LN ephemeral anchor scripts (0:50) ● Probabilistic payments (54:45) March● Bitcoin Forking Guide (3:29:35) ● Private block template marketplace to prevent centralizing MEV (3:05:28) ● LN upfront and hold fees using burnable outputs (13:12) April● SwiftSync speedup for initial block download (2:09:35) ● DahLIAS interactive aggregate signatures (3:26:02) Summary 2025: Quantum (58:07) May● Cluster mempool (1:22:11) ● Increasing or removing Bitcoin Core’s OP_RETURN policy limit (2:45:43) June● Calculating the selfish mining danger threshold (2:20:39) ● Fingerprinting nodes using addr messages (3:11:38) ● Garbled locks (3:19:01) Summary 2025: Soft fork proposals (26:57) July● Chain code delegation (49:07) August● Utreexo draft BIPs (2:15:57) ● Lowering the minimum relay feerate (2:39:52) ● Peer block template sharing (2:56:01) ● Differential fuzzing of Bitcoin and LN implementations (3:16:08) Summary 2025: Stratum v2 (2:04:49) September● Details about the design of Simplicity (3:23:01) ● Partitioning and eclipse attacks using BGP interception (3:13:47) October● Discussions about arbitrary data (3:01:15) ● Channel jamming mitigation simulation results and updates (11:05) November● Comparing performance of ECDSA signature validation in OpenSSL vs. libsecp256k1 (2:01:47) ● Modeling stale rates by propagation delay and mining centralization (2:22:32) ● BIP3 and the BIP process (3:31:37) ● Bitcoin Kernel C API introduced (3:35:35) December● Splicing (7:33)

Mark “Murch” Erhardt, Gustavo Flores Echaiz, and Mike Schmidt are joined by Matt Morehouse and Salvatore Ingala to discuss ⁠Newsletter #384⁠.News● Critical vulnerabilities fixed in LND 0.19.0 (0:59) ● A virtualized secure enclave for hardware signing devices (21:11) Changes to services and client software● Interactive transaction visualization tool (37:16) ● BlueWallet v7.2.2 released (38:20) ● Stratum v2 updates (38:42) ● Auradine announces Stratum v2 support (40:18) ● LDK Node 0.7.0 released (41:58) ● BIP-329 Python Library 1.0.0 release (43:30) ● Bitcoin Safe 1.6.0 released (44:34) Selected Q&A from Bitcoin Stack Exchange● Does a clearnet connection to my Lightning node require a TLS certificate? (45:12) ● Why do different implementations produce different DER signatures for the same private key and hash? (45:58) ● Why is the miniscript `after` value limited at 0x80000000? (49:27) Notable code and documentation changes● Bitcoin Core #33528 (53:12) ● Bitcoin Core #33723 (54:17) ● Bitcoin Core #33993 (56:35) ● Bitcoin Core #33553 (59:54) ● Eclair #3220 (1:01:52) ● LDK #4231 (1:02:48) ● LND #10396 (1:05:40) ● BTCPay Server #7022 (1:08:26) ● Rust Bitcoin #5379 (1:09:32) ● BIPs #2050 (1:10:06)

Mark “Murch” Erhardt, Gustavo Flores Echaiz, and Mike Schmidt are joined by Moonsettler and Julian to discuss Newsletter #383.News● Consensus bug in NBitcoin library (1:04) Changing consensus● LNHANCE soft fork (24:00) ● Benchmarking the varops budget (5:09) ● SLH-DSA (SPHINCS) post-quantum signature optimizations (45:29) Releases and release candidates● Core Lightning v25.12 (1:02:24) ● LDK 0.2 (1:03:43) Notable code and documentation changes● Core Lightning #8728 (1:05:14) ● Core Lightning #8702 (1:06:55) ● Core Lightning #8735 (1:07:24) ● LDK #4226 (1:11:41) ● LND #10341 (1:12:49) ● BTCPay Server #6986 (1:14:00) ● BIPs #2015 (1:16:18)

Mark “Murch” Erhardt, Gustavo Flores Echaiz, and Mike Schmidt discuss ⁠Newsletter #382⁠.News● Stats on compact block reconstructions updates (0:34) ● Motion to activate BIP3 (7:26) Selected Q&A from Bitcoin Stack Exchange● Do pruned nodes store witness inscriptions? (24:27) ● Increasing probability of block hash collisions when difficulty is too high (29:33) ● What is the purpose of the initial 0x04 byte in all extended public and private keys? (33:25) Releases and release candidates● LND v0.20.0-beta (34:57) ● Core Lightning v25.12rc1 (35:57) Notable code and documentation changes● Bitcoin Core #33872 (37:55) ● Bitcoin Core #33629 (42:05) ● Core Lightning #8677 (49:49) ● Core Lightning #8546 (51:28) ● Core Lightning #8682 (53:19) ● LDK #4197 (55:39) ● LDK #4234 (1:00:56) ● LDK #4148 (1:02:17) ● BDK #2027 (1:03:04)

Mark “Murch” Erhardt, Gustavo Flores Echaiz, and Mike Schmidt are joined by Antoine Poinsot and ZmnSCPxj to discuss Newsletter #381.News● Modeling stale rates by propagation delay and mining centralization (1:03) ● Private key handover for collaborative closure (30:55) Changes to services and client software● Arkade launches (52:32) ● Mempool monitoring mobile application (55:25) ● Web-based policy and miniscript IDE (56:25) ● Phoenix Wallet adds taproot channels (57:45) ● Nunchuk 2.0 launches (59:19) ● LN gossip traffic analysis tool announced (1:01:49) Notable code and documentation changes● Bitcoin Core #33745 (1:04:23) ● Core Lightning #8537 (1:09:28) ● Core Lightning #8608 (1:11:26) ● Core Lightning #8646 (1:13:34) ● Core Lightning #8569 (1:17:44) ● Core Lightning #8558 (1:22:46) ● LDK #4126 (1:24:11) ● LDK #4208 (1:26:37) ● LND #9432 (1:27:58) ● BOLTs #1284 (1:31:38) ● BOLTs #1044 (1:33:33)

Mark “Murch” Erhardt and Mike Schmidt are joined by TheCharlatan to discuss Newsletter #380.Releases and release candidates● LND 0.20.0-beta.rc4 (1:30) Notable code and documentation changes● Bitcoin Core #30595 (2:56) ● Bitcoin Core #33443 (28:03) ● Core Lightning #8656 (29:42) ● Core Lightning #8671 (30:22) ● LDK #4204 (33:09) ● BIPs #2022 (34:45)

Mark “Murch” Erhardt, Gustavo Flores Echaiz, and Mike Schmidt are joined by Sebastian Falbesoner, PortlandHODL, Tadge Dryja, and Antoine Poinsot to discuss Newsletter #379.News● Comparing performance of ECDSA signature validation in OpenSSL vs. libsecp256k1 (1:47) Changing consensus● Multiple discussions about restricting data (14:05) ● Post-quantum signature aggregation (1:00:05) ● Native STARK proof verification in Bitcoin Script (1:18:47) ● BIP54 implementation and test vectors (35:47) Releases and release candidates● Core Lightning 25.09.2 (1:30:54) ● LND 0.20.0-beta.rc3 (1:31:44) Notable code and documentation changes● Bitcoin Core #31645 (1:32:34) ● Core Lightning #8636 (1:40:08) ● Core Lightning #8639 (1:43:18) ● Core Lightning #8635 (1:44:31) ● Eclair #3209 (1:46:25) ● Eclair #3206 (1:46:59) ● Eclair #3210 (1:49:31) ● LDK #4140 (1:54:13) ● LDK #4168 (1:59:12) ● Rust Bitcoin #5116 (2:01:06) ● BTCPay Server #6922 (2:05:05)

Mark “Murch” Erhardt and Mike Schmidt discuss Newsletter #378.News● CPU DoS from unconfirmed transaction processing (1:00) Selected Q&A from Bitcoin Stack Exchange● Why was -datacarriersize redefined in 2022, and why was the 2023 proposal to expand it not merged? (17:53) ● What is the smallest valid transaction that can be included in a block? (22:59) ● Why does Bitcoin Core continue to give witness data a discount even when it is used for inscriptions? (25:38) ● The ever-growing Bitcoin blockchain size? (39:17) ● I read that OP_TEMPLATEHASH is a variant of OP_CTV. How do they differ? (44:59) Releases and release candidates● LND 0.20.0-beta.rc1 (49:59) ● Eclair 0.13.1 (50:43) Notable code and documentation changes● Bitcoin Core #29640 (51:21) ● Core Lightning #8400 (54:15) ● Eclair #3173 (54:53) ● LND #10280 (56:56) ● BIPs #2006 (57:27) ● BIPs #1975 (1:00:58)

Gustavo Flores Echaiz and Mike Schmidt are joined by Abubakar Sadiq Ismail and Carla Kirk-Cohen to discuss ⁠Newsletter #377⁠.News● Detecting block template feerate increases using cluster mempool (1:06) ● Channel jamming mitigation simulation results and updates (9:28) Changes to services and client software● BULL wallet launches (37:22) ● Sparrow 2.3.0 released (39:40) Releases and release candidates● Core Lightning 25.09.1 (40:47) ● Bitcoin Core 28.3 (41:18) Notable code and documentation changes● Bitcoin Core #33157 (43:00) ● Bitcoin Core #29675 (45:56) ● Bitcoin Core #33517 (46:59) ● Eclair #2792 (49:01) ● LDK #4122 (51:01) ● LND #9868 (52:37) ● LND #10273 (53:48)

Gustavo Flores Echaiz and Mike Schmidt are joined by Francesco Madonna and supertestnet to discuss Newsletter #376.News● Continued discussion of block template sharing (17:30) ● B-SSL a Secure Bitcoin Signing Layer (2:54) Releases and release candidates● Bitcoin Core 30.0 (22:32) ● Bitcoin Core 29.2 (28:44) ● LDK 0.1.6 (29:37) Notable code and documentation changes● Eclair #3184 (30:59) ● Core Lightning #8597 (32:25) ● LDK #4117 (34:05) ● LDK #4077 (35:03) ● LDK #4154 (36:47)

Gustavo Flores Echaiz and Mike Schmidt are joined by Sindura Saraswathi, ZmnSCPxj, and Eugene Siegel to discuss ⁠Newsletter #375⁠.News● Optimal Threshold Signatures (1:56) ● Flattening certain nested threshold signatures (14:33) ● Theoretical limitations on embedding data in the UTXO set (38:14) Bitcoin Core PR Review Club● Compact block harness (27:12) Releases and release candidates● Bitcoin Inquisition 29.1 (45:01) Notable code and documentation changes● Bitcoin Core #33453 (47:16) ● Bitcoin Core #33504 (51:52) ● Core Lightning #8563 (53:55) ● Core Lightning #8523 (56:55) ● Core Lightning #8398 (58:22) ● LDK #4120 (59:47) ● LND #10254 (1:01:35)

Mark “Murch” Erhardt and Mike Schmidt are joined by Gustavo Flores Echaiz to discuss Newsletter #374.Changing consensus● Draft BIPs for Script Restoration (0:40) Releases and release candidates● Bitcoin Core 30.0rc2 (19:19) ● bdk-wallet 2.2.0 (23:39) ● LND v0.20.0-beta.rc1 (24:15) Notable code and documentation changes● Bitcoin Core #33229 (25:03) ● Bitcoin Core #33446 (26:55) ● LDK #3838 (28:11) ● LDK #4098 (30:40) ● LDK #4106 (33:40) ● LDK #4096 (35:43) ● LND #10133 (37:24) ● BDK #2029 (39:08) ● BIPs #1911 (42:15)

Mark “Murch” Erhardt and Mike Schmidt are joined by Matt Morehouse, Daniela Brozzoni, and Gustavo Flores Echaiz to discuss Newsletter #373.News● Eclair vulnerability (18:50) ● Research into feerate settings (0:35) Selected Q&A from Bitcoin Stack Exchange● Implications of OP_RETURN changes in upcoming Bitcoin Core version 30.0? (28:27) ● If OP_RETURN relay limits are ineffective, why remove the safeguard instead of keeping it as a default discouragement? (42:12) ● What are the worst-case stress scenarios from uncapped OP_RETURNs in Bitcoin Core v30? (43:25) ● If OP_RETURN needed more room, why was the 80-byte cap removed instead of being raised to 160? (50:39) ● If arbitrary data is inevitable, does removing OP_RETURN limits shift demand toward more harmful storage methods (like UTXO-inflating addresses)? (59:48) ● If OP_RETURN uncapping doesn’t increase the UTXO set, how does it still contribute to blockchain bloat and centralization pressure? (1:00:17) ● How does uncapping OP_RETURN impact long-term fee-market quality and security budget? (1:02:11) ● Assurance blockchain will not suffer from illegal content with 100KB OP_RETURN? (1:04:34) ● What analysis shows OP_RETURN uncapping won’t harm block propagation or orphan risk? (1:05:25) ● Where does Bitcoin Core keep the XOR obfuscation keys for both block data files and level DB indexes? (1:06:10) ● How robust is 1p1c transaction relay in bitcoin core 28.0? (1:06:34) ● How can I allow getblocktemplate to include sub 1 sat/vbyte transactions? (1:10:37) Releases and release candidates● Bitcoin Core 30.0rc1 (1:13:00) Notable code and documentation changes● Bitcoin Core #33333 (1:15:26) ● Bitcoin Core #28592 (1:18:36) ● Eclair #3171 (1:22:33) ● Eclair #3175 (1:26:41) ● LDK #4064 (1:29:36) ● LDK #4067 (1:31:04) ● LDK #4046 (1:32:43) ● LDK #4083 (1:35:27) ● LND #10189 (1:38:23) ● BIPs #1963 (1:41:17)

Mark “Murch” Erhardt and Mike Schmidt are joined by ZmnSCPxj and Constantine Doumanidis to discuss Newsletter #372.News● LSP-funded redundant overpayments (16:24) ● Partitioning and eclipse attacks using BGP interception (1:02) Changes to services and client software● Zero-knowledge proof of reserve tool (13:49) ● Alternative submarine swap protocol proof of concept (15:12) Releases and release candidates● Bitcoin Core 30.0rc1 (39:14) ● BDK Chain 0.23.2 (1:16:28) Notable code and documentation changes● Bitcoin Core #33268 (1:17:19) ● Eclair #3157 (1:18:56) ● LND #9975 (1:19:52) ● LND #9677 (1:20:21) ● LDK #4045 (1:20:41) ● LDK #4049 (1:20:32) ● BDK #1582 (1:22:18) ● BDK #2000 (1:23:13) ● BDK #2028 (1:24:17)