Bitcoin Optech

We provide weekly newsletters, workshops, case studies, and research for the #Bitcoin community.

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Last Notes

2026-03-06 14:16:32 UTC

Bitcoin Optech newsletter #395 is here:
- describes a standard for verifying VTXOs across different Ark implementations
- links to a draft BIP for expanding the miner-usable nonce space in the block header’s nVersion field
- points to extensions to standard tooling for TEMPLATEHASH-CSFS-IK support
- summarizes updates to the Hourglass V2 proposal
- examines perspectives on cryptographic algorithm agility for Bitcoin
- Optech Newsletter #395 Podcast
https://bitcoinops.org/en/newsletters/2026/03/06/
Jgmcalpine posted to Delving Bitcoin about his proposal for V-PACK, a stateless VTXO verification standard, which aims to provide a mechanism to independently verify and visualize VTXOs in the Ark ecosystem...
https://bitcoinops.org/en/newsletters/2026/03/06/#a-standard-for-stateless-vtxo-verification
Matt Corallo posted to the Bitcoin-Dev mailing list a draft BIP to increase the number of bits available in nVersion’s nonce space for miners from 16 to 24...
https://bitcoinops.org/en/newsletters/2026/03/06/#draft-bip-for-expanded-nversion-nonce-space-for-miners
Antoine Poinsot wrote on the Bitcoin-Dev mailing list about his preliminary work to integrate the taproot-native OP_TEMPLATEHASH soft fork proposal into miniscript and PSBTs...
https://bitcoinops.org/en/newsletters/2026/03/06/#extensions-to-standard-tooling-for-templatehash-csfs-ik-support
Mike Casey posted an update to the Bitcoin-Dev mailing list for the Hourglass protocol to mitigate the market impact of quantum attacks against certain lost coins...
https://bitcoinops.org/en/newsletters/2026/03/06/#hourglass-v2-update
Ethan Heilman wrote on the Bitcoin-Dev mailing list regarding the potential need for RFC7696 Cryptographic Algorithm Agility in Bitcoin...
https://bitcoinops.org/en/newsletters/2026/03/06/#algorithm-agility-for-bitcoin
Pieter Wuille wrote to the Bitcoin-Dev mailing list about the limitations of the cryptographic agility...
https://bitcoinops.org/en/newsletters/2026/03/06/#the-limitations-of-cryptographic-agility-in-bitcoin
Bitcoin Optech will host an audio recap discussion of this newsletter streaming live on X/Twitter Tuesday at 17:30 UTC.

2026-01-06 22:36:08 UTC

Anthony Towns and Mikhail Kudinov joined Optech to discuss Newsletter #386:
- A notice about the wallet migration bug in Bitcoin Core
- Building a vault using blinded co-signers
- BIP for Peer feature negotiation
- Year 2106 timestamp overflow
- BIP54 timestamp restriction for a timestamp overflow soft fork
- Mitigating a CTV footgun
- CTV activation meeting
- OP_CHECKCONSOLIDATION to enable cheaper consolidations
- Hash-based signatures post-quantum Bitcoin
- And more
You can listen on our website:
https://bitcoinops.org/en/podcast/2026/01/06/
Fountain:
https://fountain.fm/episode/LSYvA10Nd4ToHfmuKhvX
Spotify:
https://open.spotify.com/episode/21GFU6WOODEv2s9F2NvBtB
Apple Podcasts:
https://podcasts.apple.com/us/podcast/bitcoin-optech-newsletter-386-recap/id1674626983?i=1000744026375

2025-12-19 15:30:32 UTC

Bitcoin Optech newsletter #385: 2025 Year-in-Review Special is here:
- notes Bitcoin developments during each month of 2025
- feature: Vulnerability disclosures
- feature: Quantum
- feature: Soft fork proposals
- feature: Stratum v2
- feature: Major releases of popular infrastructure projects
- feature: Optech
https://bitcoinops.org/en/newsletters/2025/12/19/
In 2025, Optech summarized more than a dozen vulnerability disclosures...
https://bitcoinops.org/en/newsletters/2025/12/19/#vulns
With the increased attention on the potential for a future quantum computer to weaken or break the Elliptic Curve Discrete Logarithm (ECDL) hardness assumption that Bitcoin relies on to prove the ownership of coins, several conversations and proposals were put forward throughout the year to discuss and mitigate the impact of such a development.
https://bitcoinops.org/en/newsletters/2025/12/19/#quantum
This year saw a bevy of discussions around soft fork proposals, ranging from the tightly scoped and minimally impactful, to the broadly scoped and powerful…
https://bitcoinops.org/en/newsletters/2025/12/19/#softforks
Stratum v2 is a mining protocol designed to replace the original Stratum protocol used between miners and mining pools. Throughout 2025, Bitcoin Core received several updates to better support Stratum v2 implementations....
https://bitcoinops.org/en/newsletters/2025/12/19/#stratumv2
Optech covered major releases of popular infrastructure projects throughout the year...
https://bitcoinops.org/en/newsletters/2025/12/19/#releases
In Optech’s eighth year, we published:
- 50 newsletters
- over 80,000 words, a 225pg book equivalent
- over 60hrs of podcasts, with 500,000 words of transcripts w/75 guests
- 150+ non-English translations
https://bitcoinops.org/en/newsletters/2025/12/19/#optech
A special thank you
After contributing as the primary author for 376 consecutive Bitcoin Optech newsletters, Dave Harding stepped back from contributing regularly this year. We cannot thank Harding enough for anchoring the newsletter for eight years and all of the Bitcoin education, elucidation, and understanding he brought the community. We are eternally grateful and wish him all the best.
Bitcoin Optech will host an audio recap discussion of this special newsletter on Riverside.fm Tuesday at 17:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-12-05 13:02:31 UTC

Bitcoin Optech newsletter #383 is here:
- describes a fixed vulnerability affecting the NBitcoin library
- summarizes the LNHANCE soft fork proposal
- relays a call to action to benchmark Bitcoin script execution under GSR's varops budget
- highlights discussion of optimizations to SLH-DSA (SPHINCS) post-quantum signatures
- Optech Newsletter #383 Podcast
https://bitcoinops.org/en/newsletters/2025/12/05/
Bruno Garcia posted to Delving Bitcoin about a theoretical consensus failure in NBitcoin that could occur when using OP_NIP...
https://bitcoinops.org/en/newsletters/2025/12/05/#consensus-bug-in-nbitcoin-library
Moonsettler proposes a soft fork for LNHANCE now that all four of its constituent opcodes have updated BIPs and reference implementations...
https://bitcoinops.org/en/newsletters/2025/12/05/#lnhance-soft-fork
Julian posted a call to action to benchmark Bitcoin script execution under the varops budget...
https://bitcoinops.org/en/newsletters/2025/12/05/#benchmarking-the-varops-budget
Continuing the discussions around hardening Bitcoin against quantum computing, conduition presented his work on optimizing the SPHINCS signing algorithm...
https://bitcoinops.org/en/newsletters/2025/12/05/#slh-dsa-sphincs-post-quantum-signature-optimizations
Bitcoin Optech will host an audio recap discussion of this newsletter on Riverside.fm Tuesday at 17:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-11-04 19:46:00 UTC

Mark “Murch” Erhardt and Mike Schmidt discuss Newsletter #378:
- Disclosure of four low-severity vulnerabilities in Bitcoin Core
- Q&A from Bitcoin Stack Exchange including questions on datacarriersize, OP_TEMPLATEHASH and others
- And more
You can listen on our website:
https://bitcoinops.org/en/podcast/2025/11/04/
Fountain:
https://fountain.fm/episode/52iLDnzzU5I7rxb8coJT
Spotify:
https://open.spotify.com/episode/3gvj03rHM7qT0jTnQcMnfH
Apple Podcasts:
https://podcasts.apple.com/us/podcast/bitcoin-optech-newsletter-378-recap/id1674626983?i=1000735256317

2025-09-16 19:13:54 UTC

Jonas Nick and Bastien Teinturier joined Optech to discuss Newsletter #371:
News
0:48 Provable Cryptography Workbook
Releases and release candidates
10:48 Bitcoin Core 29.1
11:17 Eclair v0.13.0
25:27 Bitcoin Core 30.0rc1
Notable code and documentation changes
33:18 Bitcoin Core #30469
33:18 Eclair #3163
40:27 Eclair #2308
45:18 Eclair #3021
48:08 Eclair #3142
50:30 LDK #4053
58:12 LDK #3886
You can listen on our website: https://bitcoinops.org/en/podcast/2025/09/16/
Fountain: https://fountain.fm/episode/FDSWN4dSOtzy7kezMw3G
Spotify: https://open.spotify.com/episode/240Htez9aCxIINL1rqCuWy
Apple Podcasts: https://podcasts.apple.com/us/podcast/bitcoin-optech-newsletter-371-recap/id1674626983?i=1000727098773 https://blossom.primal.net/475398338edaa3d08cad5284e9c602c62899ec01e59e3a27cc4c169dd82d12d0.mp4

2025-09-12 12:16:13 UTC

Bitcoin Optech newsletter #371 is here:
- announces the availability of a workbook dedicated to provable cryptography
- Bitcoin Core 29.1, Eclair v0.13.0, Bitcoin Core 30.0rc1
- Optech Newsletter #371 Podcast
https://bitcoinops.org/en/newsletters/2025/09/12/
Jonas Nick posted to Delving Bitcoin to announce a short workbook he created for a four day event to “teach developers the basics of provable cryptography, […] consisting of cryptographic definitions, propositions, proofs and exercises.”
https://bitcoinops.org/en/newsletters/2025/09/12/#provable-cryptography-workbook
Bitcoin Optech will host an audio recap discussion of this newsletter on Riverside.fm Tuesday at 16:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-09-10 10:51:15 UTC

Russell O’Connor, Olaoluwa Osuntokun, and Jeremy Rubin join Optech to discuss Newsletter #370:
Changing consensus
37:56 Details about the design of Simplicity
1:52 Draft BIP for adding elliptic curve operations to tapscript
19:23 Draft BIP for OP_TWEAKADD
Releases and release candidates
59:40 Core Lightning v25.09
1:00:24 Bitcoin Core 29.1rc2
Notable code and documentation changes
1:00:55 LDK #3726
1:02:24 LDK #4019
1:03:09 LND #9455
1:04:00 LND #10103
1:05:20 HWI #795
You can listen on our website: https://bitcoinops.org/en/podcast/2025/09/09/
Fountain: https://fountain.fm/episode/6IP69xVggsPJ4dZtShuf
Spotify: https://open.spotify.com/episode/1InhHmSFSrggcAxafzymWS
Apple Podcasts: https://podcasts.apple.com/us/podcast/bitcoin-optech-newsletter-370-recap/id1674626983?i=1000725872238 https://blossom.primal.net/8665d77655f96257fcc4863adf6b9346baa8248261152d36a5a366f446aa0ecf.mp4

2025-09-05 11:35:35 UTC

Bitcoin Optech newsletter #370 is here:
- details the design of Simplicity
- links to a draft BIP for adding elliptic curve operations to tapscript
- describes the draft BIP for OP_TWEAKADD
- Optech Newsletter #370 Podcast
https://bitcoinops.org/en/newsletters/2025/09/05/
Russell O’Connor made three posts so far to Delving Bitcoin about “the philosophy and design of the Simplicity language”...
https://bitcoinops.org/en/newsletters/2025/09/05/#details-about-the-design-of-simplicity
Olaoluwa Osuntokun posted to the Bitcoin-Dev mailing list a link to a draft BIP for adding several opcodes to tapscript that will allow elliptic curve operations to be performed on the script evaluation stack...
https://bitcoinops.org/en/newsletters/2025/09/05/#draft-bip-for-adding-elliptic-curve-operations-to-tapscript
Jeremy Rubin posted to the Bitcoin-Dev mailing list a link a draft BIP to add OP_TWEAKADD to tapscript...
https://bitcoinops.org/en/newsletters/2025/09/05/#draft-bip-for-op-tweakadd
Bitcoin Optech will host an audio recap discussion of this newsletter on Riverside.fm Tuesday at 16:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-08-29 11:04:24 UTC

Bitcoin Optech Newsletter #369 is here:
- shares an update on differential fuzzing of Bitcoin and LN implementations
- links to a new paper about garbled locks for accountable computing contracts
- summarizes popular Q&A from Stack Exchange
- Optech Newsletter #369 Podcast
https://bitcoinops.org/en/newsletters/2025/08/29/
Bruno Garcia posted to Delving Bitcoin to describe recent progress and accomplishments of bitcoinfuzz, a library and related data for fuzz testing Bitcoin-based software and libraries...
https://bitcoinops.org/en/newsletters/2025/08/29/#update-on-differential-fuzzing-of-bitcoin-and-ln-implementations
Liam Eagen posted to the Bitcoin-Dev mailing list about a paper he’s written about a new mechanism for creating accountable computing contracts but based on garbled circuits...
https://bitcoinops.org/en/newsletters/2025/08/29/#garbled-locks-for-accountable-computing-contracts
Selected Q&A from Bitcoin Stack Exchange:
- Is it possible to recover a private key from an aggregate public key under strong assumptions?
- Are all taproot addresses vulnerable to quantum computing?
- Why cant we set the chainstate obfuscation key?
- Is it possible to revoke a spending branch after a block height?
- Configure Bitcoin Core to use onion nodes in addition to IPv4 and IPv6 nodes?
https://bitcoinops.org/en/newsletters/2025/08/29/#selected-qa-from-bitcoin-stack-exchange
Bitcoin Optech will host an audio recap discussion of this newsletter on Riverside.fm Tuesday at 16:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-08-22 10:39:52 UTC

Bitcoin Optech Newsletter #368 is here:
- summarizes a draft BIP for block template sharing between full nodes
- announces a library that allows trusted delegation of script evaluation
- summarizes changes to services/client software
- Optech Newsletter #368 Podcast
https://bitcoinops.org/en/newsletters/2025/08/22/
Anthony Towns posted to the Bitcoin-Dev mailing list the draft of a BIP for how nodes can communicate to their peers the transactions they would attempt to mine in their next block...
https://bitcoinops.org/en/newsletters/2025/08/22/#draft-bip-for-block-template-sharing
Josh Doman posted to Delving Bitcoin about a library he’s written that uses a trusted execution environment (TEE) that will only sign a taproot keypath spend if the transaction containing that spend satisfies a script...
https://bitcoinops.org/en/newsletters/2025/08/22/#trusted-delegation-of-script-evaluation
Changes to services and client software:
- ZEUS v0.11.3 released
- Rust Utreexo resources
- Peer-observer tooling and call to action
- Bitcoin Core Kernel-based node announced
- SimplicityHL released
- LSP plugin for BTCPay Server
- Proto mining hardware and software announced
- Oracle resolution demo using CSFS
- Relai adds taproot support
https://bitcoinops.org/en/newsletters/2025/08/22/#changes-to-services-and-client-software
Bitcoin Optech will host an audio recap discussion of this newsletter on Riverside.fm Tuesday at 16:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-08-15 10:38:53 UTC

Bitcoin Optech Newsletter #367 is here:
- LND v0.19.3-beta.rc1
- Bitcoin Core 29.1rc1
- Optech Newsletter #367 Podcast
https://bitcoinops.org/en/newsletters/2025/08/15/
Bitcoin Optech will host an audio recap discussion of this newsletter on Riverside.fm Tuesday at 16:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-08-13 17:09:17 UTC

Gloria Zhao and Mike Schmidt were joined by Tadge Dryja and Anthony Towns to discuss Newsletter #366:
- Draft BIPs proposed for Utreexo
- Continued discussion about lowering the minimum relay feerate
- Peer block template sharing to mitigate problems with divergent mempool policies
- A watch only wallet PR Review Club
- And more
You can listen on our website:
https://bitcoinops.org/en/podcast/2025/08/12/
Fountain:
https://fountain.fm/episode/mb22hz065ESbbtqZvMy6
Spotify:
https://open.spotify.com/episode/58sQEBHrZ5Z22iUID6x5Je
Apple Podcasts:
https://podcasts.apple.com/us/podcast/bitcoin-optech-newsletter-366-recap/id1674626983?i=1000721833977

2025-08-06 16:28:02 UTC

David Gumberg, Lauren Shareshian, Jameson Lopp, Steven Roose, and Tim Ruffing joined Optech to discuss Newsletter #365:
- Compact block prefilling
- Mempool-based fee estimation
- Migration from quantum-vulnerable outputs
- The OP_TEMPLATEHASH proposal
- Proposal to allow longer relative timelocks
- Security against quantum computers with taproot as a commitment scheme
- And more
You can listen on our website:
https://bitcoinops.org/en/podcast/2025/08/05/
Spotify:
https://open.spotify.com/episode/65CJxx41a9UYQhCvHDrXWX
Apple Podcasts:
https://podcasts.apple.com/us/podcast/bitcoin-optech-newsletter-365-recap/id1674626983?i=1000720913277

2025-07-31 15:55:42 UTC

Matt Morehouse and Jesse Posner (@jesseposner) joined Optech to discuss Newsletter #364:
News
0:53 LND gossip filter DoS vulnerability
15:16 Chain code withholding for multisig scripts
38:46 Research indicates common Bitcoin primitives are compatible with quantum-resistant signature algorithms
Selected Q&A from Bitcoin Stack Exchange
57:36 How does Bitcoin Core handle reorgs larger than 10 blocks?
1:01:29 Advantages of a signing device over an encrypted drive?
1:03:21 Spending a taproot output through the keypath and scriptpath?
Releases and release candidates
1:04:26 Libsecp256k1 v0.7.0
Notable code and documentation changes
1:05:16 Bitcoin Core #32521
1:15:00 Bitcoin Core #31829
1:19:51 LDK #3801
1:21:11 LDK #3842
1:21:57 BIPs #1890
1:23:53 BOLTs #1232 https://blossom.primal.net/4c846fc1e4ad14a94b7dea486210f63fc22c3329c5ea1219e175177cf104d6bb.mp4

2025-07-25 12:26:00 UTC

Bitcoin Optech newsletter #364 is here:
- summarizes a vulnerability affecting old versions of LND
- describes an idea for improving privacy when using co-signer services
- examines the impact of switching to quantum-resistant signature algorithms on HD wallets, scriptless multisig, and silent payments
- summarizes popular Q&A from Stack Exchange
- Optech Newsletter #364 Recap
https://bitcoinops.org/en/newsletters/2025/07/25/
Matt Morehouse posted to Delving Bitcoin about a vulnerability affecting past versions of LND that he previously responsibly disclosed...
https://bitcoinops.org/en/newsletters/2025/07/25/#lnd-gossip-filter-dos-vulnerability
Jurvis Tan posted to Delving Bitcoin about research he performed with Jesse Posner into improving the privacy and security of multisig collaborative custody...
https://bitcoinops.org/en/newsletters/2025/07/25/#chain-code-withholding-for-multisig-scripts
Jesse Posner posted to Delving Bitcoin several links to research papers that indicate that quantum-resistant signature algorithms provide comparable primitives to those currently used in Bitcoin...
https://bitcoinops.org/en/newsletters/2025/07/25/#research-indicates-common-bitcoin-primitives-are-compatible-with-quantum-resistant-signature-algorithms
Selected Q&A from Bitcoin Stack Exchange:
- How does Bitcoin Core handle reorgs larger than 10 blocks?
- Advantages of a signing device over an encrypted drive?
- Spending a taproot output through the keypath and scriptpath?
https://bitcoinops.org/en/newsletters/2025/07/25/#selected-qa-from-bitcoin-stack-exchange
Bitcoin Optech will host an audio recap discussion of this newsletter on Riverside.fm Tuesday at 16:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-07-22 19:20:32 UTC

- reply

You can listen on our website:
https://bitcoinops.org/en/podcast/2025/07/22/
Spotify:
https://open.spotify.com/episode/1OufUqtuvQxEXOPJBsqAwH
Apple Podcasts:
https://podcasts.apple.com/us/podcast/bitcoin-optech-newsletter-363-recap/id1674626983?i=1000718502522

2025-07-16 14:46:15 UTC

Josh Doman and Gloria Zhao joined Optech to discuss ⁠⁠Newsletter #362⁠⁠:
News
0:34 Compressed descriptors
Bitcoin Core PR Review Club
9:14 Improve TxOrphanage denial of service bounds
Releases and release candidates
46:22 LND v0.19.2-beta.rc2
Notable code and documentation changes
47:17 Core Lightning #8377
50:41 BDK #1957
51:18 BIPs #1888
https://blossom.primal.net/6326fc5b174dbe7ab4563a04806daaefdb8d259403e176c179f876604735063c.mp4

2025-07-11 09:56:35 UTC

Bitcoin Optech newsletter #362 is here:
- briefly describes a new library allowing output script descriptors to be compressed for use in QR codes
- recaps the "Improve TxOrphanage denial of service bounds" PR Review Meeting
- #362 Recap Podcast
https://bitcoinops.org/en/newsletters/2025/07/11/
Josh Doman posted to Delving Bitcoin to announce a library he’s written that encodes output script descriptors into a binary format that reduces their size by about 40%...
https://bitcoinops.org/en/newsletters/2025/07/11/#compressed-descriptors
Improve TxOrphanage denial of service bounds is a PR by glozow that changes TxOrphanage eviction logic to guarantee each peer the resources for at least 1 maximum-size package worth of orphan resolution...
https://bitcoinops.org/en/newsletters/2025/07/11/#bitcoin-core-pr-review-club
Bitcoin Optech will host an audio recap discussion of this newsletter on Riverside.fm Tuesday at 16:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-07-10 14:42:27 UTC

Sanket Kanjalkar, Jonas Nick, Tadge Dryja, Steven Roose, and Brandon Black joined Optech this week to discuss:
- A new onion message network
- CTV+CSFS and benefits to PTLCs and BitVM
- Vault descriptors
- The CTV and CSFS open letter
- Winternitz signatures using OP_CAT
- Commit/reveal function for post-quantum recovery
- OP_TXHASH variant with support for transaction sponsorship
- And more
https://bitcoinops.org/en/podcast/2025/07/08/

2025-07-04 12:45:27 UTC

Bitcoin Optech newsletter #361 is here:
- describes a proposal to separate the network connections and peer management used for onion message relay from those used for HTLC relay in LN
- CTV+CSFS advantages for PTLCs
- Vault output script descriptor
- Continued discussion about CTV+CSFS advantages for BitVM
- Open letter about CTV and CSFS
- OP_CAT enables Winternitz signatures
- Commit/reveal function for post-quantum recovery
- OP_TXHASH variant with support for transaction sponsorship
- Optech Newsletter #361 Recap Podcast
https://bitcoinops.org/en/newsletters/2025/07/04/
Olaluwa Osuntokun posted to Delving Bitcoin about allowing nodes to use separate connections for relaying onion messages than they use for relaying HTLCs...
https://bitcoinops.org/en/newsletters/2025/07/04/#separating-onion-message-relay-from-htlc-relay
Developers continued a previous discussion about the benefits of OP_CHECKTEMPLATEVERIFY (CTV), OP_CHECKSIGFROMSTACK (CSFS), or both together for various deployed and imagined protocols...
https://bitcoinops.org/en/newsletters/2025/07/04/#ctv-csfs-advantages-for-ptlcs
Sjors Provoost posted to Delving Bitcoin to discuss how the recovery information for a wallet using vaults could be specified using an output script descriptor...
https://bitcoinops.org/en/newsletters/2025/07/04/#vault-output-script-descriptor
Developers continued the previous discussion about how the availability of OP_CHECKTEMPLATEVERIFY (CTV) and OP_CHECKSIGFROMSTACK (CSFS) opcodes could “reduce [BitVM] transaction sizes by approximately 10x” and allow non-interactive peg-ins...
https://bitcoinops.org/en/newsletters/2025/07/04/#continued-discussion-about-ctv-csfs-advantages-for-bitvm
James O’Beirne posted an open letter to the Bitcoin-Dev mailing signed by 66 individuals (as of this writing), many of them contributors to Bitcoin-related projects...
https://bitcoinops.org/en/newsletters/2025/07/04/#open-letter-about-ctv-and-csfs
Developer Conduition posted to the Bitcoin-Dev mailing list a prototype implementation that uses the proposed OP_CAT opcode and other Script instructions to allow quantum-resistant signatures using the Winternitz protocol to be verified by consensus logic...
https://bitcoinops.org/en/newsletters/2025/07/04/#op-cat-enables-winternitz-signatures
Tadge Dryja posted to the Bitcoin-Dev mailing list a method for allowing individuals to spend UTXOs using quantum-vulnerable signature algorithms even if fast quantum computers would otherwise allow redirecting (stealing) the output of any attempted spend...
https://bitcoinops.org/en/newsletters/2025/07/04/#commit-reveal-function-for-post-quantum-recovery
Steven Roose posted to Delving Bitcoin about a variation on OP_TXHASH called TXSIGHASH that extends 64-byte schnorr signatures with additional bytes to indicate what fields in the transaction (or related transactions) the signature commits to...
https://bitcoinops.org/en/newsletters/2025/07/04/#op-txhash-variant-with-support-for-transaction-sponsorship
Bitcoin Optech will host an audio recap discussion of this newsletter on Riverside.fm Tuesday at 16:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-06-12 19:22:24 UTC

Jose SK, Clara Shikhelman, Vojtěch Strnad, Robin Linus, and Dan Gould joined @nprofile…mzvs and @nprofile…tz3n to discuss:
- Syncing full nodes without witnesses
- Quantum computing report
- Transaction weight limit with exception to prevent confiscation
- Removing outputs from the UTXO set based on value and time
- And More…
Catch up:
https://bitcoinops.org/en/podcast/2025/06/10/

2025-05-30 12:29:53 UTC

Bitcoin Optech newsletter #356 is here:
- summarizes a discussion about the possible effects of attributable failures on LN privacy
- summarizes popular Q&A from Stack Exchange
- adds an attributable failures topic
- Optech Newsletter #356 Recap Podcast
https://bitcoinops.org/en/newsletters/2025/05/30/
Carla Kirk-Cohen posted to Delving Bitcoin an analysis of the possible consequences for the privacy of LN spenders and receivers if the network adopts attributable failures, particularly telling the spender the amount of time it took to forward a payment at each hop...
https://bitcoinops.org/en/newsletters/2025/05/30/#do-attributable-failures-reduce-ln-privacy
Selected Q&A from Bitcoin Stack Exchange:
- Which transactions get into blockreconstructionextratxn?
- Why would anyone use OP_RETURN over inscriptions, aside from fees?
- Why is my Bitcoin node not receiving incoming connections?
- How do I configure my node to filter out transactions larger than 400 bytes?
- What does “not publicly routable” node in Bitcoin Core P2P mean?
- Why would a node would ever relay a transaction?
- Is selfish mining still an option with compact blocks and FIBRE?
https://bitcoinops.org/en/newsletters/2025/05/30/#selected-qa-from-bitcoin-stack-exchange
Attributable failures are LN payment forwarding failures or delays that can be attributed to a pair of nodes, allowing spenders to avoid using slow or failure-prone nodes for future payments...
https://bitcoinops.org/en/topics/attributable-failures/
Bitcoin Optech will host an audio recap discussion of this newsletter on Riverside.fm Tuesday at 16:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-05-23 11:36:28 UTC

Bitcoin Optech newsletter #355 is here:
- summarizes changes to services/client software
- LND 0.19.0-beta, Core Lightning 25.05rc1 releases
- Optech Newsletter #355 Recap Podcast
https://bitcoinops.org/en/newsletters/2025/05/23/
Changes to services and client software:
- Cake Wallet added payjoin v2 support
- Sparrow adds pay-to-anchor features
- Safe Wallet 1.3.0 released
- COLDCARD Q v1.3.2 released
- Transaction batching using payjoin
- JoinMarket Fidelity Bond Simulator
- Bitcoin opcodes documented
- Bitkey code open sourced
https://bitcoinops.org/en/newsletters/2025/05/23/#changes-to-services-and-client-software
Bitcoin Optech will host an audio recap discussion of this newsletter on Riverside.fm Tuesday at 16:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-05-16 11:01:26 UTC

Bitcoin Optech newsletter #354 is here:
- describes a fixed vulnerability affecting old versions of Bitcoin Core
- Changing consensus covering: 64-bit arithmetic in Script, Proposed opcodes for enabling recursive covenants through quines, benefits to BitVM from OP_CTV and OP_CSFS
- Optech Newsletter #354 Recap Podcast
https://bitcoinops.org/en/newsletters/2025/05/16/
Antoine Poinsot posted to the Bitcoin-Dev mailing list to announce a vulnerability affecting Bitcoin Core versions before 29.0...
https://bitcoinops.org/en/newsletters/2025/05/16/#vulnerability-disclosure-affecting-old-versions-of-bitcoin-core
Chris Stewart posted a draft BIP to the Bitcoin-Dev mailing list that proposes upgrading Bitcoin’s existing opcodes to operate on 64-bit numeric values...
https://bitcoinops.org/en/newsletters/2025/05/16/#proposed-bip-for-64-bit-arithmetic-in-script
Bram Cohen posted to Delving Bitcoin to suggest a set of simple opcodes that would enable the creation of recursive covenants through self-reproducing scripts (quines)...
https://bitcoinops.org/en/newsletters/2025/05/16/#proposed-opcodes-for-enabling-recursive-covenants-through-quines
Robin Linus posted to Delving Bitcoin about several of the improvements to BitVM that would become possible if the proposed OP_CTV and OP_CSFS opcodes were added to Bitcoin in a soft fork...
https://bitcoinops.org/en/newsletters/2025/05/16/#description-of-benefits-to-bitvm-from-op-ctv-and-op-csfs
Bitcoin Optech will host an audio recap discussion of this newsletter on Riverside.fm Tuesday at 16:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-05-15 14:42:53 UTC

Earlier this week @nprofile…mzvs and @nprofile…tz3n discussed Newsletter #353 with Ruben Somsen, Salvatore Ingala, and Stéphan Vuylsteke:
- BIP30 consensus failure vulnerability
- Avoiding BIP32 path reuse
- Bitcoin Core’s multiprocess project
- And more…
Catch up:
https://bitcoinops.org/en/podcast/2025/05/13/

2025-05-02 20:00:38 UTC

Bitcoin Optech newsletter #352 is here:
- links to comparisons between different cluster linearization techniques
- briefly summarizes discussion about increasing or removing Bitcoin Core’s OP_RETURN size limit
- Optech Newsletter #352 Recap
https://bitcoinops.org/en/newsletters/2025/05/02/
Pieter Wuille posted to Delving Bitcoin about some of the fundamental tradeoffs between three different cluster linearization techniques, following up with benchmarks of implementations of each...
https://bitcoinops.org/en/newsletters/2025/05/02/#comparison-of-cluster-linearization-techniques
In a thread on Bitcoin-Dev, several developers discussed changing or removing Bitcoin Core’s default limit for OP_RETURN data carrier outputs. A subsequent Bitcoin Core pull request saw additional discussion...
https://bitcoinops.org/en/newsletters/2025/05/02/#increasing-or-removing-bitcoin-core-s-op-return-size-limit
Bitcoin Optech will host an audio recap discussion of this newsletter on Riverside.fm Tuesday at 16:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-04-04 11:39:49 UTC

Bitcoin Optech newsletter #348 is here:
- links to an educational implementation of elliptic curve cryptography for Bitcoin’s secp256k1 curve
- Changing consensus covering: discussions about quantum computer theft and resistance, a CTV+CSFS soft fork, OP_CHECKCONTRACTVERIFY semantics, and a consensus cleanup draft BIP
- Optech Newsletter #348 Recap on Riverside
https://bitcoinops.org/en/newsletters/2025/04/04/
Sebastian Falbesoner, Jonas Nick, and Tim Ruffing posted to the Bitcoin-Dev mailing list to announce a Python implementation of various functions related to the cryptography used in Bitcoin...
https://bitcoinops.org/en/newsletters/2025/04/04/#educational-and-experimental-based-secp256k1-implementation
Several conversations examined how Bitcoiners could respond to quantum computers becoming powerful enough to allow stealing bitcoins...
https://bitcoinops.org/en/newsletters/2025/04/04/#multiple-discussions-about-quantum-computer-theft-and-resistance
Several conversations examined various aspects of soft forking in the OP_CHECKTEMPLATEVERIFY (CTV) and OP_CHECKSIGFROMSTACK (CSFS) opcodes...
https://bitcoinops.org/en/newsletters/2025/04/04/#multiple-discussions-about-a-ctv-csfs-soft-fork
Salvatore Ingala posted to Delving Bitcoin to describe the semantics of the proposed OP_CHECKCONTRACTVERIFY (CCV) opcode, link to a first draft BIP, and link to an implementation draft for Bitcoin Core...
https://bitcoinops.org/en/newsletters/2025/04/04/#op-checkcontractverify-semantics
Antoine Poinsot posted to the Bitcoin-Dev mailing list a link to a draft BIP he’s written for the consensus cleanup soft fork proposal. It includes several fixes...
https://bitcoinops.org/en/newsletters/2025/04/04/#draft-bip-published-for-consensus-cleanup
Bitcoin Optech will host an audio recap discussion of this newsletter on Riverside.fm Tuesday at 15:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-03-26 15:30:28 UTC

Yesterday @nprofile…d0r5 and @nprofile…tz3n were joined by Matt Morehouse, Yong Yu, Alejandro De La Torre, Jan B, and Marco De Leon to discuss Newsletter #346:
- LND's dynamic feerate adjustment system
- DMND launching pooled mining
- Bitcoin Core 29.0rc2 and testing guide
- Removing checkpoints in Bitcoin Core
- And more!
Catch up:
https://bitcoinops.org/en/podcast/2025/03/25/

2025-03-14 10:53:30 UTC

Bitcoin Optech newsletter #345 is here:
- looks at an analysis of P2P traffic experienced by a typical full node
- summarizes research into LN pathfinding
- describes a new approach for creating probabilistic payments
- recaps the "Stricter internal handling of invalid blocks " PR Review Meeting
- Optech Newsletter #345 Recap on Riverside
https://bitcoinops.org/en/newsletters/2025/03/14/
Developer Virtu posted to Delving Bitcoin an analysis of the network traffic generated and received by his node in four different modes: initial block download (IBD), non-listening (outbound connections only), non-archival (pruned) listening, and archival listening...
https://bitcoinops.org/en/newsletters/2025/03/14/#p2p-traffic-analysis
Sindura Saraswathi posted to Delving Bitcoin about research she conducted with Christian Kümmerle about finding optimal paths between LN nodes for sending payments in a single part...
https://bitcoinops.org/en/newsletters/2025/03/14/#research-into-single-path-ln-pathfinding
Robin Linus replied to the Delving Bitcoin thread about probabilistic payments with a conceptually simple script that allows two parties to each commit to an arbitrary amount of entropy that can later be revealed and xored together, to produce a value that can be used to determine which one of them receives a payment...
https://bitcoinops.org/en/newsletters/2025/03/14/#probabilistic-payments-using-different-hash-functions-as-an-xor-function
'Stricter internal handling of invalid blocks' is a PR by mzumsande that improves the correctness of two non-consensus-critical and expensive-to-calculate validation fields by immediately updating them when a block is marked as invalid...
https://bitcoinops.org/en/newsletters/2025/03/14/#bitcoin-core-pr-review-club
Bitcoin Optech will host an audio recap discussion of this newsletter on Riverside.fm Tuesday at 15:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-03-11 19:41:09 UTC

Earlier today @nprofile…d0r5 and @nprofile…tz3n were joined by Matt Morehouse , @nprofile…z2zr , and @nprofile…0g64 to discuss Newsletter #343:
- LND vulnerability
- Bitcoin Core’s priorities
- Bitcoin Forking Guide
- Update on BIP360 pay-to-quantum-resistant-hash (P2QRH)
- Private block template marketplace to prevent centralizing MEV
- and more!
Catch up:
https://bitcoinops.org/en/podcast/2025/03/11/

2025-02-18 20:07:06 UTC

Earlier today @nprofile…d0r5 and @nprofile…tz3n discussed Bitcoin Optech Newsletter #341:
- probabilistic payments
- ephemeral anchors
- Bitcoin network monitoring and orphan evictions
- BIP3
- cluster mempool
... and more!
Catch up:
https://bitcoinops.org/en/podcast/2025/02/18/

2025-02-15 10:06:19 UTC

Earlier this week Optech was joined by Matt Morehouse, Johan Halseth, Pieter Wuille, Sergi Delgado, Bastien Teinturier, Oleksandr Kurbatov, Antoine Poinsot and Bob McElrath to discuss Newsletter #340.
Catch up:
https://bitcoinops.org/en/podcast/2025/02/11/

2025-02-07 11:23:40 UTC

Bitcoin Optech newsletter #340 is here:
- announces a fixed vulnerability affecting LDK
- summarizes discussion about zero-knowledge gossip for LN channel announcements
- describes the discovery of previous research that can be applied to finding optimal cluster linearizations
- provides an update on the development of the Erlay protocol for reducing transaction relay bandwidth
- looks at tradeoffs between different scripts for implementing LN ephemeral anchors
- relays a proposal for emulating an OP_RAND opcode in a privacy-preserving manner with no consensus changes required
- points to renewed discussion about lowering the minimum transaction feerate
- Optech Newsletter #340 Recap on Riverside
https://bitcoinops.org/en/newsletters/2025/02/07/
Matt Morehouse posted to Delving Bitcoin to announce a vulnerability affecting LDK that he responsibly disclosed and which was fixed in LDK version 0.1.1...
https://bitcoinops.org/en/newsletters/2025/02/07/#channel-force-closure-vulnerability-in-ldk
Johan Halseth posted to Delving Bitcoin with an extension to the proposed 1.75 channel announcement protocol that would allow other nodes to verify that a channel was backed by a funding transaction, preventing multiple cheap DoS attacks, but without revealing which UTXO is the funding transaction—enhancing privacy...
https://bitcoinops.org/en/newsletters/2025/02/07/#zero-knowledge-gossip-for-ln-channel-announcements
Stefan Richter posted to Delving Bitcoin about a research paper from 1989 he found that has a proven algorithm that can be used to efficiently find the highest-feerate subset of a group of transactions that will be topologically valid if the subset is included in a block...
https://bitcoinops.org/en/newsletters/2025/02/07/#discovery-of-previous-research-for-finding-optimal-cluster-linearization
Sergi Delgado made several posts to Delving Bitcoin about his work over the past year implementing Erlay for Bitcoin Core...
https://bitcoinops.org/en/newsletters/2025/02/07/#erlay-update
Bastien Teinturier posted to Delving Bitcoin to ask for opinions about what ephemeral anchor script should be used as one of the outputs to TRUC-based LN commitment transactions as a replacement for existing anchor outputs...
https://bitcoinops.org/en/newsletters/2025/02/07/#tradeoffs-in-ln-ephemeral-anchor-scripts
Oleksandr Kurbatov posted to Delving Bitcoin about an interactive protocol that allows two parties to make a contract that will pay out in a way that neither can predict, which is functionally equivalent to randomly...
https://bitcoinops.org/en/newsletters/2025/02/07/#emulating-op-rand
Greg Tonoski posted to the Bitcoin-Dev mailing list about lowering the default minimum transaction relay feerate...
https://bitcoinops.org/en/newsletters/2025/02/07/#discussion-about-lowering-the-minimum-transaction-relay-feerate
Antoine Poinsot made several posts to the Delving Bitcoin thread about the consensus cleanup soft fork suggesting parameter changes...
https://bitcoinops.org/en/newsletters/2025/02/07/#updates-to-cleanup-soft-fork-proposal
Bob McElrath posted to Delving Bitcoin requesting developers working on covenant designs to consider how their favorite proposal, or a new proposal, could assist in the creation of an efficient decentralized mining pool...
https://bitcoinops.org/en/newsletters/2025/02/07/#request-for-a-covenant-design-supporting-braidpool
A thread from April 2024 received renewed attention this past month. Previously, Bob McElrath posted about having miners commit to the transactions in their mempool and then only allowing them to include transactions in their blocks that were deterministically selected from previous commitments...
https://bitcoinops.org/en/newsletters/2025/02/07/#deterministic-transaction-selection-from-a-committed-mempool
Developer Zawy posted to Delving Bitcoin about a mining difficulty adjustment algorithm (DAA) for a directed acyclic graph (DAG) type blockchain...
https://bitcoinops.org/en/newsletters/2025/02/07/#fast-difficulty-adjustment-algorithm-for-a-dag-blockchain
Difficulty adjustment algorithms
Difficulty adjustment algorithms (DAAs) are the methods by which mining difficulty is regulated, which affects the average time between blocks, the total amount of block space, and the rate of distribution of new bitcoins (the block subsidy)...
https://bitcoinops.org/en/topics/difficulty-adjustment-algorithms/
Bitcoin Optech will host an audio recap discussion of this newsletter with special guests Matt Morehouse, Bastien Teinturier, Bob McElrath, and Antoine Poinsot on Riverside.fm Tuesday at 15:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-01-31 14:08:50 UTC

Bitcoin Optech newsletter #339 is here:
- describes a vulnerability affecting older versions of LDK
- looks at a newly disclosed aspect of a vulnerability originally published in 2023
- summarizes renewed discussion about compact block reconstruction statistics
- summarizes popular Q&A from Stack Exchange
- Optech Newsletter #339 Recap on Riverside
Matt Morehouse posted to Delving Bitcoin to disclose a vulnerability affecting LDK that he responsibly disclosed and which was fixed in LDK version 0.1...
Antoine Riard posted to the Bitcoin-Dev mailing list to disclose an additional vulnerability possible with the replacement cycling attack he originally publicly disclosed in 2023...
Developer 0xB10C posted to Delving Bitcoin updated stats on the frequency at which his Bitcoin Core nodes needed to request additional transactions to perform compact block reconstruction...
Selected Q&A from Bitcoin Stack Exchange:
- Who uses or wants to use PSBTv2 (BIP370)?
- In the bitcoin’s block genesis, which parts can be filled arbitrarily?
- Lightning force close detection
- Is a segwit-formatted transaction with all inputs of non-witness program type valid?
- P2TR Security Question
- What exactly is being done today to make Bitcoin “quantum-safe”?
- What are the harmful effects of a shorter inter-block time?
- Could proof-of-work be used to replace policy rules?
- How does MuSig work in real Bitcoin scenarios?
- How does the -blocksxor switch that obfuscates the blocks.dat files work?
- How does the related key attack on Schnorr signatures work?
https://bitcoinops.org/en/newsletters/2025/01/31/
Bitcoin Optech will host an audio recap discussion of this newsletter with special guest Matt Morehouse on Riverside.fm Tuesday at 15:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2025-01-28 18:24:06 UTC

Earlier today @nprofile…d0r5 and @nprofile…tz3n sat down with Andrew Toth and @nprofile…cvw0 to discuss Newsletter #338:
- unspendable script descriptor expression
- who is using PSBTs v2 and why?
- Off chain rolling DLCs
-12 changes to services and client software
Catch up:
https://bitcoinops.org/en/podcast/2025/01/28/

2025-01-14 19:10:08 UTC

Earlier today Murch and Schmidty discussed Newsletter #336 with Abubakar Sadiq, Gregory Sanders, and Daniel Roberts:
- Double coinbase reservation
- LN-Symmetry
and more...
Catch up:
https://bitcoinops.org/en/podcast/2025/01/14/

2025-01-03 16:15:24 UTC

Bitcoin Optech would like your feedback!
Let us know in this survey what parts of the newsletter and website are valuable for you and how we can make Optech an even better Bitcoin technical resource.
https://forms.gle/RknVv5Etx4D5MVVt8

2025-01-03 15:22:07 UTC

Bitcoin Optech newsletter #335 is here:
- links to information about longstanding deanonymization vulnerabilities in software using centralized coinjoin protocols
- summarizes an update to a draft BIP about the ChillDKG distributed key generation protocol compatible with scriptless threshold signing
- adds a new monthly section summarizing proposals and discussion about changing Bitcoin’s consensus rules
- Optech Newsletter #335 Recap on Riverside
https://bitcoinops.org/en/newsletters/2025/01/03/
Yuval Kogman posted to the Bitcoin-Dev mailing list details about several privacy-reducing vulnerabilities in the centralized coinjoin protocols used by current versions of the Wasabi and Ginger wallets, plus past versions of the Samourai, Sparrow, and Trezor Suite software wallets...
https://bitcoinops.org/en/newsletters/2025/01/03/#deanonymization-attacks-against-centralized-coinjoin
Tim Ruffing and Jonas Nick posted to the Bitcoin-Dev mailing list a link to the current draft BIP for ChillDKG, which describes a distributed key generation protocol compatible with FROST scriptless threshold signatures for Bitcoin...
https://bitcoinops.org/en/newsletters/2025/01/03/#updated-chilldkg-draft
Changing consensus:
- CTV enhancement opcodes
- Adjusting difficulty beyond 256 bits
- Transitory soft forks for cleanup soft forks
- Quantum computer upgrade path
- Consensus cleanup timewarp grace period
https://bitcoinops.org/en/newsletters/2025/01/03/#changing-consensus
Bitcoin Optech will host an audio recap discussion of this newsletter with special guest Yuval Kogman on Riverside.fm Tuesday at 15:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2024-12-20 12:48:35 UTC

Bitcoin Optech newsletter #334: 2024 Year-in-Review Special is here:
- notes Bitcoin developments during each month of 2024
- feature: Vulnerability disclosures
- feature: Cluster mempool
- feature: P2P transaction relay
- feature: Covenants and script upgrades
- feature: Major releases of popular infrastructure projects
- feature: Optech
https://bitcoinops.org/en/newsletters/2024/12/20/
In 2024, Optech summarized more than two dozen vulnerability disclosures...
https://bitcoinops.org/en/newsletters/2024/12/20/#vulnreports
An idea for a mempool redesign from 2023 became a particular focus for several Bitcoin Core developers throughout 2024...
https://bitcoinops.org/en/newsletters/2024/12/20/#cluster
Fee management has always been a challenge in the decentralized Bitcoin protocol, but widespread use of contract protocols such as LN-Penalty and ongoing research into newer and more complex protocols has made it more important than ever to ensure users can pay and increase fees on demand. Bitcoin Core contributors have been working on this problem for years, and 2024 saw the public release of several new features that significantly improve the situation...
https://bitcoinops.org/en/newsletters/2024/12/20/#p2prelay
Several developers devoted much of their time in 2024 towards advancing proposals for covenants, scripting upgrades, and other changes that would support advanced contract protocols such as joinpools and channel factories...
https://bitcoinops.org/en/newsletters/2024/12/20/#covs
Optech covered major releases of popular infrastructure projects throughout the year...
https://bitcoinops.org/en/newsletters/2024/12/20/#releases
In Optech’s seventh year, we published:
- 51 newsletters
- 35 new topic pages
- over 120,000 words, a 350pg book equivalent
- a wallet guide for developers
- over 59hr of podcasts, with 488,000 words of transcripts w/75 guests
- 200+ non-English translations
https://bitcoinops.org/en/newsletters/2024/12/20/#optech
Bitcoin Optech will host an audio recap discussion of this special newsletter with special guests Dave Harding, Niklas Gögge, Gloria Zhao, and Brandon Black on Riverside.fm Monday at 15:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2024-12-13 11:39:32 UTC

Bitcoin Optech newsletter #333 is here:
- describes a vulnerability that allowed stealing from old versions of various LN implementations
- announces a deanonymization vulnerability affecting Wasabi and related software
- summarizes a post and discussion about LN channel depletion
- links to a poll for opinions about selected covenant proposals
- describes two types of incentive-based pseudo-covenants
- references summaries of the periodic in-person Bitcoin Core developer meeting
- recaps the "Track and use all potential peers for orphan resolution" PR Review Meeting
- summarizes changes to services/client software
- summarizes popular Q&A from Stack Exchange
- Optech Newsletter #333 Recap on Riverside
https://bitcoinops.org/en/newsletters/2024/12/13/
David Harding announced to Delving Bitcoin a vulnerability he had responsibly disclosed earlier in the year. Old versions of Eclair, LDK, and LND with default settings allowed the party who opened a channel to steal up to 98% of channel value...
https://bitcoinops.org/en/newsletters/2024/12/13/#vulnerability-allowing-theft-from-ln-channels-with-miner-assistance
A developer of GingerWallet disclosed a method a coinjoin coordinator could use to prevent users from gaining any privacy during a coinjoin...
https://bitcoinops.org/en/newsletters/2024/12/13/#deanonymization-vulnerability-affecting-wasabi-and-related-software
René Pickhardt posted to Delving Bitcoin and participated, along with Christian Decker, in an Optech Deep Dive about his research into the mathematical foundations of payment channel networks...
https://bitcoinops.org/en/newsletters/2024/12/13/#insights-into-channel-depletion
/dev/fd0 posted to the Bitcoin-Dev mailing list a link to a public poll of developer opinions about selected covenant proposals...
https://bitcoinops.org/en/newsletters/2024/12/13/#poll-of-opinions-about-covenant-proposals
Jeremy Rubin posted to the Bitcoin-Dev mailing list a link to a paper he authored about oracle-assisted covenants. The model involves two oracles: a covenant oracle and an integrity oracle...
https://bitcoinops.org/en/newsletters/2024/12/13/#incentive-based-pseudo-covenants
Many Bitcoin Core developers met in person in October, and several notes from the meeting have now been published...
https://bitcoinops.org/en/newsletters/2024/12/13/#bitcoin-core-developer-meeting-summaries
'Track and use all potential peers for orphan resolution' is a PR by glozow that improves the reliability of orphan resolution by letting the node request missing ancestors from all peers instead of just the one that announced the orphan...
https://bitcoinops.org/en/newsletters/2024/12/13/#bitcoin-core-pr-review-club
Changes to services and client software:
- Java-based HWI released
- Saving Satoshi Bitcoin development education game announced
- Neovim Bitcoin Script plugin
- Proton Wallet adds RBF
https://bitcoinops.org/en/newsletters/2024/12/13/#changes-to-services-and-client-software
Selected Q&A from Bitcoin Stack Exchange:
- How long does Bitcoin Core store forked chains?
- What is the point of solo mining pools?
- Is there a point to using P2TR over P2WSH if I only want to use the script path?
https://bitcoinops.org/en/newsletters/2024/12/13/#selected-qa-from-bitcoin-stack-exchange
Bitcoin Optech will host an audio recap discussion of this newsletter with special guests Dave Harding and /dev/fd0 on Riverside.fm Tuesday at 15:30 UTC. Join us to discuss or ask questions!
https://riverside.fm/studio/bitcoin-optech

2024-12-03 13:56:21 UTC

- reply

We needed to move this discussion with AJ Towns to 14:30 UTC today.
Hope to see you there!
https://riverside.fm/studio/bitcoin-optech

2024-11-15 16:41:52 UTC

Bitcoin Optech newsletter #329 is here:
- summarizes a new offchain payment resolution protocol
- links to papers about potential IP-layer tracking and censorship of LN payments
- BTCPay Server security fixes
- adds an LN-Penalty topic
- adds a Timeout trees topic
- Optech Newsletter #329 Recap on Twitter Spaces
https://bitcoinops.org/en/newsletters/2024/11/15/
John Law posted to Delving Bitcoin the description of a micropayment protocol that requires both participants to contribute funds to a bond that can be effectively destroyed at any time by either participant...
https://bitcoinops.org/en/newsletters/2024/11/15/#mad-based-offchain-payment-resolution-opr-protocol
Charmaine Ndolo posted to Delving Bitcoin summaries of two recent papers about reducing the privacy of LN payments and potentially censoring them...
https://bitcoinops.org/en/newsletters/2024/11/15/#papers-about-ip-layer-censorship-of-ln-payments
BTCPay Server 2.0.3 and 1.13.7 are maintenance releases that include security critical fixes for users of certain plugins and features...
https://bitcoinops.org/en/newsletters/2024/11/15/#btcpay-server-2-0-3
LN-Penalty is a state protocol that penalizes a party who publishes a past state by allowing their funds to be seized by their counterparty...
https://bitcoinops.org/en/topics/ln-penalty/
Timeout trees are a type of trustless contract protocol that produces a tree of offchain transactions that only remain safe against counterparty theft for a limited period of time (i.e., they time out)...
https://bitcoinops.org/en/topics/timeout-trees/
Bitcoin Optech will host an audio recap discussion of this newsletter on Twitter Spaces Tuesday at 15:30 UTC. Join us to discuss or ask questions!
https://x.com/i/spaces/1lDxLlkMpnvxm

2024-11-01 10:51:16 UTC

Bitcoin Optech newsletter #327 is here:
- describes a proposal for timeout tree channel factories
- summarizes a draft BIP for proofs of discrete log equivalence to be used when generating silent payments
- adds a discrete log equivalency (DLEQ) topic
- adds a duplex micropayment channels topic
- Optech Newsletter #327 Recap on Twitter Spaces
https://bitcoinops.org/en/newsletters/2024/11/01/
ZmnSCPxj posted to Delving Bitcoin and discussed with Optech contributors a proposal for a new multi-layer channel factory design named SuperScalar...
https://bitcoinops.org/en/newsletters/2024/11/01/#timeout-tree-channel-factories
Andrew Toth posted to the Bitcoin-Dev mailing list a draft BIP and a link to an implementation for generating and verifying proofs of discrete log equality (DLEQ) for the elliptic curve used by Bitcoin (secp256k1)...
https://bitcoinops.org/en/newsletters/2024/11/01/#draft-bip-for-dleq-proofs
Discrete log equivalency (DLEQ) or proofs of discrete log equivalency (PODLE) is the ability to prove two points on an elliptic curve were both derived from the same private value (such as a private key)...
https://bitcoinops.org/en/topics/discrete-log-equivalency/
Duplex micropayment channels are bi-directional micropayment channels that use deincrementing relative time locks to ensure the latest state is the first that can be confirmed.
https://bitcoinops.org/en/topics/duplex-micropayment-channels/
Bitcoin Optech will host an audio recap discussion of this newsletter with special guest Andrew Toth on Twitter Spaces Tuesday at 14:30 UTC. Join us to discuss or ask questions!
https://x.com/i/spaces/1lDxLlkZXaMxm

2024-10-10 20:09:34 UTC

Bitcoin Core 28.0 includes a number of new P2P and mempool policy features that may be useful for businesses and users.
In this blog post, Gregory Sanders summarizes the feature set and how they can be used individually or together.
The guide explains and provides command line samples for:
- One Parent One Child (1P1C) Relay
- TRUC Transactions
- 1P1C-topology Package RBF
- Pay To Anchor (P2A)
as well as describing common wallet patterns that can benefit: simple payments, coinjoins, LN, Ark, LN splicing
https://bitcoinops.org/en/bitcoin-core-28-wallet-integration-guide/

2024-09-20 10:42:26 UTC

Bitcoin Optech newsletter #321 is here:
- links to a proof-of-concept implementation for
proving in zero-knowledge that an output is part of the UTXO set
- describes one new and two previous proposals for allowing offline LN
payments
- summarizes research about DNS seeding for non-IP network
addresses
- summarizes changes to services/client software
- Optech Newsletter #321 Recap on Twitter Spaces
https://bitcoinops.org/en/newsletters/2024/09/20/
Johan Halseth posted to Delving Bitcoin to announce a proof-of-concept tool that allows someone to prove that they control one of the outputs in the current UTXO set without revealing which output...
https://bitcoinops.org/en/newsletters/2024/09/20/#proving-utxo-set-inclusion-in-zero-knowledge
Andy Schroder posted to Delving Bitcoin to sketch a communication process an LN wallet could use to generate tokens that could be provided to an internet-connected wallet in order to pay it...
https://bitcoinops.org/en/newsletters/2024/09/20/#ln-offline-payments
Virtu posted to Delving Bitcoin a survey of the availability of seed nodes on anonymity networks and discussed methods for allowing new nodes that exclusively use those networks to learn about peers through DNS seeders...
https://bitcoinops.org/en/newsletters/2024/09/20/#dns-seeding-for-non-ip-addresses
Changes to services and client software:
- Strike adds BOLT12 support
- BitBox02 adds silent payment support
- The Mempool Open Source Project v3.0.0 released
- ZEUS v0.9.0 released
- Live Wallet adds consolidation support
- Bisq adds Lightning support
https://bitcoinops.org/en/newsletters/2024/09/20/#changes-to-services-and-client-software
Bitcoin Optech will host an audio recap discussion of this newsletter on Twitter Spaces Tuesday at 14:30 UTC. Join us to discuss or ask questions!
https://twitter.com/i/spaces/1RDGlywwRREJL

2024-08-02 11:19:24 UTC

Bitcoin Optech newsletter #314 is here:
- announces the disclosure of two vulnerabilities affecting older versions of Bitcoin Core
- summarizes a proposed approach to optimizing miner transaction selection when cluster mempool is in use
- highlights a network event simulator for the Bitcoin P2P network
- Optech Newsletter #314 Recap on Twitter Spaces
https://bitcoinops.org/en/newsletters/2024/08/02/
Niklas Gögge posted to the Bitcoin-Dev mailing list a link to announcements of two vulnerabilities affecting versions of Bitcoin Core that have been past their end of life since at least October 2022...
https://bitcoinops.org/en/newsletters/2024/08/02/#disclosure-of-vulnerabilities-affecting-bitcoin-core-versions-before-0-21-0
Pieter Wuille posted to Delving Bitcoin about ensuring that miner block templates can include the best set of transactions when using cluster mempool...
https://bitcoinops.org/en/newsletters/2024/08/02/#optimizing-block-building-with-cluster-mempool
Sergi Delgado posted to Delving Bitcoin about Hyperion, a network simulator he’s written that tracks how data propagates through a simulated Bitcoin network...
https://bitcoinops.org/en/newsletters/2024/08/02/#hyperion-network-event-simulator-for-the-bitcoin-p2p-network
Bitcoin Optech will host an audio recap discussion of this newsletter on Twitter Spaces Tuesday at 14:30 UTC. Join us to discuss or ask questions!
https://twitter.com/i/spaces/1ynJODgpgawxR

2024-05-31 11:30:37 UTC

Bitcoin Optech newsletter #305 is here:
- describes a proposed light client protocol for silent payments
- summarizes two new proposed descriptors for taproot
- links to a discussion about whether opcodes with overlapping features should be added in a soft fork
- summarizes popular Q&A from Stack Exchange
- Optech Newsletter #305 Recap on Twitter Spaces
https://bitcoinops.org/en/newsletters/2024/05/31/
Setor Blagogee posted to Delving Bitcoin to describe a draft specification for a protocol to help lightweight clients receive silent payments (SPs)...
https://bitcoinops.org/en/newsletters/2024/05/31/#light-client-protocol-for-silent-payments
Oghenovo Usiwoma posted to Delving Bitcoin about two new proposed descriptors for constructing taproot spend conditions...
https://bitcoinops.org/en/newsletters/2024/05/31/#raw-taproot-descriptors
Pierre Rochard asks if proposed soft forks that can provide much of the same features at a similar cost should be considered mutually exclusive, or whether it would make sense to activate multiple proposals and let developers use whichever alternative they prefer...
https://bitcoinops.org/en/newsletters/2024/05/31/#should-overlapping-soft-fork-proposals-be-considered-mutually-exclusive
Selected Q&A from Bitcoin Stack Exchange:
- What’s the smallest possible coinbase tx / block size?
- Understanding Script’s number encoding, CScriptNum
- Is there a way to make an address public but hide how many BTC it contains?
- Testing increased feerates in regtest
- Why is my P2P_V2 peer connected over a v1 connection?
- Does a P2PKH tx send to the hash of the uncompressed or compressed key?
- What are different ways to broadcast a block to the Bitcoin network?
https://bitcoinops.org/en/newsletters/2024/05/31/#selected-qa-from-bitcoin-stack-exchange
Bitcoin Optech will host an audio recap discussion of this newsletter with special guests Oghenovo Usiwoma and Pierre Rochard on Twitter Spaces Tuesday at 14:30 UTC. Join us to discuss or ask questions!
https://twitter.com/i/spaces/1eaKbgnYgOBGX

2024-02-21 11:56:41 UTC

Bitcoin Optech newsletter #290 is here:
- describes a proposal for providing DNS-based human-readable Bitcoin payment instructions
- summarizes a post with thoughts about mempool incentive compatibility
- links to a thread discussing the design of Cashu and other ecash systems
- looks at continuing discussion about 64-bit arithmetic
- gives an overview of an improved reproducible ASMap creation process
- summarizes changes to services/client software
- Optech #290 Recap
https://bitcoinops.org/en/newsletters/2024/02/21/
Following previous discussions, Matt Corallo posted to Delving Bitcoin a draft BIP that will allow a string like example@example.com to resolve to DNS address such as example.user._bitcoin-payment.example.com...
https://bitcoinops.org/en/newsletters/2024/02/21/#dns-based-human-readable-bitcoin-payment-instructions
Suhas Daftuar posted to Delving Bitcoin several insights into the criteria full nodes can use to select which transactions to accept into their mempools, relay to other nodes, and mine for maximal revenue...
https://bitcoinops.org/en/newsletters/2024/02/21/#thinking-about-mempool-incentive-compatibility
Several weeks ago, developer Thunderbiscuit posted to Delving Bitcoin a description of the blind signature scheme behind the Chaumian ecash system used in Cashu, which denominates balances in satoshis and allows sending and receiving money using Bitcoin and LN...
https://bitcoinops.org/en/newsletters/2024/02/21/#cashu-and-other-ecash-system-design-discussion
Several developers have continued discussing a potential future soft fork that could add 64-bit arithmetic operations to Bitcoin.
This week, Chris Stewart created a new discussion thread for a draft BIP for an opcode originally proposed as part of OP_TAPLEAF_UPDATE_VERIFY, OP_INOUT_AMOUNT...
https://bitcoinops.org/en/newsletters/2024/02/21/#continued-discussion-about-64-bit-arithmetic-and-op-inout-amount-opcode
Fabian Jahr posted to Delving Bitcoin about advancements in creating a map of autonomous systems (ASMap) that each control the routing for large parts of the internet...
https://bitcoinops.org/en/newsletters/2024/02/21/#improved-reproducible-asmap-creation-process
Changes to services and client software:
- Multiparty coordination protocol NWC announced
- Mutiny Wallet v0.5.7 released
- GroupHug transaction batching service
- Boltz announces taproot swaps
https://bitcoinops.org/en/newsletters/2024/02/21/#changes-to-services-and-client-software
Bitcoin Optech will host an audio recap discussion of this newsletter with special guests callebtc, Chris Stewart, and Fabian Jahr on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions!
https://twitter.com/i/spaces/1kvJpvpWjwwKE

2024-02-07 14:21:38 UTC

Bitcoin Optech newsletter #288 is here:
- announces the disclosure of a block stalling bug in Bitcoin Core affecting LN
- relays a concern about how to securely open new zero-conf channels with version 3 relay
- describes a contract protocol rule when allowing an external party to contribute an input to a tx
- summarizes discussions about a proposal for new tx replacement rules to avoid pinning
- provides a brief update on the mailing list
- #288 Recap on Twitter Spaces
https://bitcoinops.org/en/newsletters/2024/02/07/
Eugene Siegel announced to Delving Bitcoin a bug in Bitcoin Core he had responsibly disclosed almost three years ago. Bitcoin Core 22 and higher contain fixes for the bug, but many people are still running affected versions...
https://bitcoinops.org/en/newsletters/2024/02/07/#public-disclosure-of-a-block-stalling-bug-in-bitcoin-core-affecting-ln
Matt Corallo posted to Delving Bitcoin to discuss how to securely allow zero-conf channel opening when the proposed v3 transaction relay policy is being used...
https://bitcoinops.org/en/newsletters/2024/02/07/#securely-opening-zero-conf-channels-with-v3-transactions
Bastien Teinturier posted to Delving Bitcoin to describe an easy-to-overlook requirement for protocols where a third party contributes an input to a transaction whose txid must not change after a different user contributes a signature to the transaction...
https://bitcoinops.org/en/newsletters/2024/02/07/#requirement-to-verify-inputs-use-segwit-in-protocols-vulnerable-to-txid-malleability
Peter Todd posted to the Bitcoin-Dev mailing list a proposal for a set of transaction replacement policies that can be used even when existing replace-by-fee (RBF) policies won’t allow a transaction to be replaced...
https://bitcoinops.org/en/newsletters/2024/02/07/#proposal-for-replace-by-feerate-to-escape-pinning
As of this writing, the Bitcoin-Dev mailing list is no longer accepting new emails as part of the process of migrating it to a different list server. Optech will provide an update when the migration is complete.
https://bitcoinops.org/en/newsletters/2024/02/07/#bitcoin-dev-mailing-list-migration-update
Bitcoin Optech will host an audio recap discussion of this newsletter with special guest Bastien Teinturier on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions!
https://twitter.com/i/spaces/1OyKAWlAaewJb

2024-01-17 12:12:38 UTC

Bitcoin Optech newsletter #285 is here:
- discloses a past vulnerability affecting Core Lightning
- announces two new soft fork proposals
- provides an overview of the cluster mempool proposal
- relays information about an updated specification and implementation of transaction compression
- summarizes a discussion about Miner Extractable Value (MEV) in non-zero ephemeral anchors
- adds an Ark topic
- Optech Newsletter #285 Recap on Twitter Spaces
https://bitcoinops.org/en/newsletters/2024/01/17/
Matt Morehouse used Delving Bitcoin to announce a vulnerability he had previously responsibly disclosed that affected Core Lightning versions 23.02 through 23.05.2...
https://bitcoinops.org/en/newsletters/2024/01/17/#disclosure-of-past-vulnerability-in-core-lightning
Brandon Black posted to Delving Bitcoin details about a soft fork that combines previous proposals for OP_CHECKTEMPLATEVERIFY (CTV) and OP_CHECKSIGFROMSTACK (CSFS) with a new proposal for an OP_INTERNALKEY that places the taproot internal key on the stack...
https://bitcoinops.org/en/newsletters/2024/01/17/#new-lnhance-combination-soft-fork-proposed
Chris Stewart posted a draft BIP to Delving Bitcoin for enabling 64-bit arithmetic operations on Bitcoin in a future soft fork. Bitcoin currently only allows 32-bit operations...
https://bitcoinops.org/en/newsletters/2024/01/17/#proposal-for-64-bit-arithmetic-soft-fork
Suhas Daftuar posted a summary of the cluster mempool proposal to Delving Bitcoin. Optech attempted to summarize the current state of cluster mempool discussion in Newsletter #280 but we would strongly recommend reading the overview by Daftuar, who is one of the architects of the proposal...
https://bitcoinops.org/en/newsletters/2024/01/17/#overview-of-cluster-mempool-proposal
Tom Briar posted to the Bitcoin-Dev mailing list an updated draft specification and proposed implementation of compressed Bitcoin transactions...
https://bitcoinops.org/en/newsletters/2024/01/17/#updated-specification-and-implementation-of-bitcoin-transaction-compression
Gregory Sanders posted to Delving Bitcoin to discuss concerns about ephemeral anchor outputs that contain more than 0 satoshis...
https://bitcoinops.org/en/newsletters/2024/01/17/#discussion-of-miner-extractable-value-mev-in-non-zero-ephemeral-anchors
Ark is a trustless joinpool-style protocol where a large number of users share a UTXO by accepting a counterparty as a co-signer on all transactions within a certain time period. This spreads the cost of onchain fees from using that UTXO across many users, minimizing their individual costs...
https://bitcoinops.org/en/topics/ark/
Bitcoin Optech will host an audio recap discussion of this newsletter with special guests Brandon Black, Chris Stewart, and Gregory Sanders on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions!
https://twitter.com/i/spaces/1ypKdkjOkoYxW

2024-01-03 11:14:09 UTC

Bitcoin Optech newsletter #283 is here:
- shares the disclosure of past vulnerabilities in LND
- summarizes a proposal for fee-dependent timelocks
- describes an idea for improving fee estimation using transaction clusters
- discusses how to specify unspendable keys in descriptors
- examines the cost of pinning in the v3 transaction relay proposal
- mentions a proposed BIP to allow descriptors to be included in PSBTs
- announces a tool that can be used with the MATT proposal to prove a program executed correctly
- looks at a proposal for allowing highly efficient group exits from a pooled UTXO
- points to new coin selection strategies being proposed for Bitcoin Core
- Optech Newsletter #283 Recap on Twitter Spaces
https://bitcoinops.org/en/newsletters/2024/01/03/
Niklas Gögge posted to Delving Bitcoin about two vulnerabilities he had previously responsibly disclosed, which led to fixed versions of LND being released...
https://bitcoinops.org/en/newsletters/2024/01/03/#disclosure-of-past-lnd-vulnerabilities
John Law posted to the Bitcoin-Dev and Lightning-Dev mailing lists with a rough proposal for a soft fork that could allow transaction timelocks to optionally only unlock (expire) when median block feerates are below a user-chosen level...
https://bitcoinops.org/en/newsletters/2024/01/03/#fee-dependent-timelocks
Abubakar Sadiq Ismail posted to Delving Bitcoin about using some of the tools and insights from the design of cluster mempool to improve fee estimation in Bitcoin Core...
https://bitcoinops.org/en/newsletters/2024/01/03/#cluster-fee-estimation
Salvatore Ingala started a discussion on Delving Bitcoin about how to allow descriptors, particularly those for taproot, to specify a key for which no private key is known (preventing spending from that key)...
https://bitcoinops.org/en/newsletters/2024/01/03/#how-to-specify-unspendable-keys-in-descriptors
Peter Todd posted to the Bitcoin-Dev mailing list an analysis of the proposed v3 transaction relay policy on transaction pinning for contract protocols such as LN...
https://bitcoinops.org/en/newsletters/2024/01/03/#v3-transaction-pinning-costs
The SeedHammer team posted a draft BIP to the Bitcoin-Dev mailing list for including descriptors in PSBTs. The main intended use seems to be encapsulating descriptors in the PSBT format for transfer between wallets, as the proposed standard allows PSBTs to omit transaction data when a descriptor is enclosed...
https://bitcoinops.org/en/newsletters/2024/01/03/#descriptors-in-psbt-draft-bip
Johan Torås Halseth posted to Delving Bitcoin about elftrace, a proof of concept program that can use the OP_CHECKCONTRACTVERIFY opcode from the MATT soft fork proposal to allow a party in a contract protocol to claim money if an arbitrary program executed successfully...
https://bitcoinops.org/en/newsletters/2024/01/03/#verification-of-arbitrary-programs-using-proposed-opcode-from-matt
Salvatore Ingala posted to Delving Bitcoin a proposal that can improve multiparty contracts where several users share a UTXO, such as a joinpool or channel factory, and some of the users want to exit the contract at a time when other users are unresponsive (whether unintentionally or deliberately)...
https://bitcoinops.org/en/newsletters/2024/01/03/#pool-exit-payment-batching-with-delegation-using-fraud-proofs
Mark Erhardt posted to Delving Bitcoin about edge-cases users may have experienced with Bitcoin Core’s coin selection strategy and proposes two new strategies that address the edge cases by attempting to reduce the number of inputs used in wallet transactions at high feerates...
https://bitcoinops.org/en/newsletters/2024/01/03/#new-coin-selection-strategies
Bitcoin Optech will host an audio recap discussion of this newsletter with special guests Niklas Gögge, Antoine Riard, Abubakar Sadiq Ismail, Salvatore Ingala, and Gloria Zhao on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions!
https://twitter.com/i/spaces/1YqKDgrwgONxV

2023-12-20 13:47:30 UTC

Bitcoin Optech newsletter #282: 2023 Year-in-Review Special is here:
- notes Bitcoin developments during each month of 2023
- feature: Soft fork proposals
- feature: Security disclosures
- feature: Major releases of popular infrastructure projects
- feature: Bitcoin Optech
https://bitcoinops.org/en/newsletters/2023/12/20/
This year saw much discussion and many proposals around potential soft forks...
https://bitcoinops.org/en/newsletters/2023/12/20/#softforks
Optech reported on three significant security vulnerabilities this year...
https://bitcoinops.org/en/newsletters/2023/12/20/#security
Optech covered major releases of popular infrastructure projects throughout the year...
https://bitcoinops.org/en/newsletters/2023/12/20/#releases
In Optech’s sixth year, we published 51 weekly newsletters, published a 10-part series about mempool policy, and added 15 new pages to our topics index. Optech published over 86,000 English words about Bitcoin research and development this year, the equivalent of a 250-page book.
Every newsletter this year was accompanied by a podcast episode, totaling over 50 hours in audio form and 450,000 words in transcript form with a total of 62 different guests in 2023...
https://bitcoinops.org/en/newsletters/2023/12/20/#optech
Bitcoin Optech will host an audio recap discussion of this special newsletter with special guest and Optech contributor Dave Harding on Twitter Spaces Thursday at 15:00 UTC. Join us to celebrate, discuss, or ask questions!
https://twitter.com/i/spaces/1BRJjPaAMNeKw

2023-11-08 11:23:47 UTC

Bitcoin Optech newsletter #276 is here:
- announces an upcoming change to the Bitcoin-Dev mailing list
- briefly summarizes a proposal to allow aggregating multiple HTLCs together
- recaps the "Fee Estimator updates from Validation Interface/CScheduler thread" PR Review Meeting
- Bitcoin Core 26.0rc2 release candidate
- Optech Newsletter #276 Recap on Twitter Spaces
https://bitcoinops.org/en/newsletters/2023/11/08/
Administrators for the Bitcoin-Dev mailing list announced that the organization hosting the list plans to cease hosting any mailing lists after the end of the year.
The administrators sought feedback from the community about options...
https://bitcoinops.org/en/newsletters/2023/11/08/#mailing-list-hosting
Johan Torås Halseth posted to the Lightning-Dev mailing list a suggestion for using a covenant to aggregate multiple HTLCs into a single output that could be spent all at once if a party knew all the preimages...
https://bitcoinops.org/en/newsletters/2023/11/08/#htlc-aggregation-with-covenants
'Fee Estimator updates from Validation Interface/CScheduler thread' is a PR by Abubakar Sadiq Ismail (ismaelsadeeq) that modifies the way the transaction fee estimator data is updated. It moves fee estimator updates from occurring synchronously during mempool updates to instead occur asynchronously...
https://bitcoinops.org/en/newsletters/2023/11/08/#bitcoin-core-pr-review-club
Bitcoin Core 26.0rc2 is a release candidate for the next major version of the predominant full node implementation.
There’s a scheduled meeting of the Bitcoin Core PR Review Club dedicated to testing on 15 November 2023.
https://bitcoincore.reviews/v26-rc-testing
Bitcoin Optech will host an audio recap discussion of this newsletter with special guests Johan Torås Halseth and Abubakar Ismail on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions!
https://twitter.com/i/spaces/1gqxvQwkqOgJB

2023-09-27 08:48:03 UTC

Bitcoin Optech newsletter #270 is here:
- describes a proposal to use covenants to significantly improve LN’s scalability
- summarizes popular Q&A from Stack Exchange
- Optech Newsletter #270 Recap on Twitter Spaces
https://bitcoinops.org/en/newsletters/2023/09/27/
John Law posted to the Bitcoin-Dev and Lightning-Dev mailing lists the summary of a paper he’s written about creating very large channel factories using covenants and managing the resultant channels using adaptations of several previous protocols he’s described...
https://bitcoinops.org/en/newsletters/2023/09/27/#using-covenants-to-improve-ln-scalability
Selected Q&A from Bitcoin Stack Exchange:
- How did peer discovery work in Bitcoin v0.1?
- Could reorgs cause Bitcoin to break because of the 2-hour block time restriction?
- Is there a way to download blocks from scratch without downloading block headers first?
- Where is the 21 million hard cap stated? - Are blocks containing non-standard transactions relayed through the network?
- When does Bitcoin Core allow you to “Abandon transaction”?
https://bitcoinops.org/en/newsletters/2023/09/27/#selected-qa-from-bitcoin-stack-exchange
Bitcoin Optech will host an audio recap discussion of this newsletter with special guest Anthony Towns on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions!
https://twitter.com/i/spaces/1yNGaZaYOWbJj

2023-09-20 09:26:29 UTC

Bitcoin Optech newsletter #269 is here:
- shares the announcement of an upcoming research event
- summarizes changes to services/client software
- Optech Newsletter #269 Recap on Twitter Spaces
https://bitcoinops.org/en/newsletters/2023/09/20/
Sergi Delgado Segura and Clara Shikhelman posted to the Bitcoin-Dev and Lightning-Dev mailing lists to announce a Bitcoin Research Day event to be held in New York City on October 27th...
https://bitcoinops.org/en/newsletters/2023/09/20/#bitcoin-research-event
Changes to services and client software:
- Bitcoin-like Script Symbolic Trace (B’SST) released
- STARK header chain verifier demo
- JoinMarket v0.9.10 released
- BitBox adds miniscript
- Machankura announces additive batching feature
- SimLN Lightning simulation tool
https://bitcoinops.org/en/newsletters/2023/09/20/#changes-to-services-and-client-software
Bitcoin Optech will host an audio recap discussion of this newsletter with special guest Sergi Delgado Segura on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions!
https://twitter.com/i/spaces/1OwGWYavZpkxQ?s=20

2023-09-13 10:52:49 UTC

Bitcoin Optech newsletter #268 is here:
- links to draft specifications related to taproot assets - describes a summary of several alternative message protocols for LN that can help enable the use of PTLCs - recaps the BIP324 "Transport abstraction" PR Review Meeting - adds a Client-side validation topic - Optech Newsletter #268 Recap on Twitter Spaces
https://bitcoinops.org/en/newsletters/2023/09/13/
Olaoluwa Osuntokun posted separately to the Bitcoin-Dev and Lightning-Dev mailing lists about the Taproot Assets client-side validation protocol. To the Bitcoin-Dev mailing list, he announced seven draft BIPs...
https://bitcoinops.org/en/newsletters/2023/09/13/#specifications-for-taproot-assets
As the first LN implementation with experimental support for channels using P2TR and MuSig2 is expected to be released soon, Greg Sanders posted to the Lightning-Dev mailing list a summary of several different previously-discussed changes to LN messages to allow them to support sending payments with PTLCs instead of HTLCs...
https://bitcoinops.org/en/newsletters/2023/09/13/#ln-messaging-changes-for-ptlcs
'Transport abstraction' is a recently-merged PR by Pieter Wuille (sipa) that introduces a transport abstraction (interface class). This PR is part of the BIP324 Version 2 P2P Encrypted Transport Protocol project...
https://bitcoinops.org/en/newsletters/2023/09/13/#bitcoin-core-pr-review-club
Client-side validation protocols allow a Bitcoin transaction to commit to some data whose validity is determined separate from the validity of the transaction under Bitcoin’s consensus rules. The client-side validation can take advantage of consensus rules, such as only allowing an output to be spent once within a valid block chain, but it may also impose additional rules known only to those interested in the validation...
https://bitcoinops.org/en/topics/client-side-validation/
Bitcoin Optech will host an audio recap discussion of this newsletter with special guests Olaoluwa Osuntokun, Greg Sanders, and Pieter Wuille on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions!
https://twitter.com/i/spaces/1ypKddqdRLjKW

2023-07-26 11:03:49 UTC

Bitcoin Optech newsletter #261 is here:
- describes a protocol for simplifying the communication related to mutual closing of LN channels
- summarizes notes from a recent meeting of LN developers
- summarizes popular Q&A from Stack Exchange
- Adds Topics for: Channel announcements, Cluster mempool, Redundant overpayments
- Optech Newsletter #261 Recap on Twitter Spaces
https://bitcoinops.org/en/newsletters/2023/07/26/
Rusty Russell posted to the Lightning-Dev mailing list a proposal that simplifies the process of two LN nodes mutually closing a channel they share...
https://bitcoinops.org/en/newsletters/2023/07/26/#simplified-ln-closing-protocol
Carla Kirk-Cohen posted to the Lightning-Dev mailing list a summary of several discussions from the recent meeting of LN developers in New York City...
https://bitcoinops.org/en/newsletters/2023/07/26/#ln-summit-notes
Selected Q&A from Bitcoin Stack Exchange:
- How can I manually (on paper) calculate a Bitcoin public key from a private key?
- Why are there 17 native segwit versions?
- Does 0 OP_CSV force the spending transaction to signal BIP125 replaceability?
- How do route hints affect pathfinding?
- What does it mean that the security of 256-bit ECDSA, and therefore Bitcoin keys, is 128 bits?
https://bitcoinops.org/en/newsletters/2023/07/26/#selected-qa-from-bitcoin-stack-exchange
Channel announcements are advertisements that a channel is available to forward payments. The advertisements are relayed through the LN gossip network...
https://bitcoinops.org/en/topics/channel-announcements/
Cluster mempool is a proposal to associate each unconfirmed transaction in a mempool with related transactions, creating a cluster. Each cluster of transactions, whether it be a single transaction or several transactions, can be ordered from most desirable to mine to least desirable, allowing operations for adding or removing new clusters to complete fast enough to use them in P2P network code...
https://bitcoinops.org/en/topics/cluster-mempool/
Redundant overpayments are LN payments split into parts where the spender sends a greater amount and more parts than necessary to pay the receiver’s invoice.
Even if some of the parts fail to arrive at the receiver’s node on the first try due to forwarding failures, enough of the other parts may arrive to allow the receiver to claim their invoiced amount...
https://bitcoinops.org/en/topics/redundant-overpayments/
Bitcoin Optech will be hosting an audio recap discussion of this newsletter with special guests Greg Sanders and Bastien Teinturier on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions!
https://twitter.com/i/spaces/1DXGyvjzgXNJM

2023-07-19 10:23:10 UTC

Bitcoin Optech newsletter #260 is here:
- includes 'Waiting for confirmation #10: Get Involved' from our series about policies for transaction relay and mempool inclusion
- summarizes changes to services/client software
- Optech Newsletter #260 Recap on Twitter Spaces
https://bitcoinops.org/en/newsletters/2023/07/19/
Waiting for confirmation #10: Get Involved
We hope this series has given readers a better idea of what’s going on while they are waiting for confirmation. We started with a discussion about how some of the ideological values of Bitcoin translate to its structure and design goals. The distributed structure of the peer-to-peer network offers increased censorship resistance and privacy over a typical centralized model...
https://bitcoinops.org/en/newsletters/2023/07/19/#waiting-for-confirmation-10-get-involved
Changes to services and client software:
- Wallet 10101 beta testing pooling funds between LN and DLCs
- LDK Node announced
- Payjoin SDK announced
- Validating Lightning Signer (VLS) beta announced
- BitGo adds MuSig2 support
- Peach adds RBF support
- Phoenix wallet adds splicing support
- Mining Development Kit call for feedback
- Binance adds Lightning support
- Nunchuk adds CPFP support
https://bitcoinops.org/en/newsletters/2023/07/19/#changes-to-services-and-client-software
Bitcoin Optech will be hosting an audio recap discussion of this newsletter with special guest Gloria Zhao on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions!
https://twitter.com/i/spaces/1OdKrzzpmLkKX

2023-06-07 11:04:42 UTC

- reply

Johan Torås Halseth posted to the Bitcoin-Dev mailing list about using the OP_CHECKOUTPUTCONTRACTVERIFY opcode (COCV) from the Merklize All The Things (MATT) proposal to replicate the functionality of the OP_CHECKTEMPLATEVERIFY proposal.
https://bitcoinops.org/en/newsletters/2023/06/07/#using-matt-to-replicate-ctv-and-manage-joinpools