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Bitcoin Optech
_@bitcoinops.org
npub1hkuk...432p
We provide weekly newsletters, workshops, case studies, and research for the #Bitcoin community.
Yesterday @npub1j5mp...sd5c @schmidty spoke with Eugene Siegel, Chris Stewart, Bram Cohen, and Robin Linus: - A disclosed Bitcoin Core vulnerability - 64 bit arithmetic draft BIP - A new approach to recursive covenants - BitVM benefits from CTV and CSFS - And more Catch up:
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 Antoine Poinsot posted to the Bitcoin-Dev mailing list to announce a vulnerability affecting Bitcoin Core versions before 29.0... 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... 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)... 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... 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!
Bitcoin Optech newsletter #353 is here: - describes a recently discovered theoretical consensus failure vulnerability - links to a proposal to avoid reuse of BIP32 wallet paths - recaps the "Add bitcoin wrapper executable" PR Review Meeting - Optech Newsletter #353 Recap Ruben Somsen posted to the Bitcoin-Dev mailing list about a theoretical consensus failure that could occur now that checkpoints have been removed from Bitcoin Core... Kevin Loaec posted to Delving Bitcoin to discuss options for preventing the same BIP32 wallet path from being used with different wallets, which could lead to a loss of privacy due to output linking and a theoretical loss of security... "Add bitcoin wrapper executable" is a PR by ryanofsky that introduces a new bitcoin binary which can be used to discover and launch the various Bitcoin Core binaries... 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!
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 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... 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... 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!
Yesterday @npub1j5mp...sd5c and @schmidty had on Jonas Nick and Salvatore Ingala to cover Newsletter #351: - The DahLIAS Interactive aggregate signatures compatible with secp256k1 - Standardized backup for wallet descriptors - Stack Exchange questions including: half-aggregated schnorr signatures, OP_RETURN, reorg statistics, and more Catch up:
Bitcoin Optech newsletter #351 is here: - announces a new aggregate signature protocol compatible with secp256k1 - describes a standardized backup scheme for wallet descriptors - summarizes popular Q&A from Stack Exchange - Optech Newsletter #351 Recap Jonas Nick, Tim Ruffing, Yannick Seurin posted to the Bitcoin-Dev mailing list to announce a paper they’ve written about creating 64-byte aggregate signatures compatible with the cryptographic primitives already used by Bitcoin... Salvatore Ingala posted to Delving Bitcoin a summary of various tradeoffs related to backing up wallet descriptors and a proposed scheme that should be useful for many different types of wallets, including those using complex scripts... Selected Q&A from Bitcoin Stack Exchange: - Practicality of half-aggregated schnorr signatures? - What’s the largest size OP_RETURN payload ever created? - Non-LN explanation of pay-to-anchor? - Up-to-date statistics about chain reorganizations? - Are Lightning channels always P2WSH? - Child-pays-for-parent as a defense against a double spend? - What values does CHECKTEMPLATEVERIFY hash? - Why can’t Lightning nodes opt to reveal channel balances for better routing efficiency? - Does post-quantum require hard fork or soft fork? 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!
In Podcast #348 we had on Jonas Nick, Jameson Lopp, Steven Roose, Gregory Sanders, and Salvatore Ingala: - secp256k1lab - discussions about quantum computer theft and resistance - discussions about a CTV+CSFS soft fork - OP_CHECKCONTRACTVERIFY - Consensus cleanup draft BIP - And more! Catch up:
Bitcoin Optech newsletter #350 is here: - summarizes changes to services/client software - Bitcoin Core 29.0 - issues a correction to some details from our story last week about SwiftSync - Optech Newsletter #350 Recap Changes to services and client software: - Bitcoin Knots version 28.1.knots20250305 released - PSBTv2 explorer announced - LNbits v1.0.0 released - The Mempool Open Source Project® v3.2.0 released - Coinbase MPC library released - Lightning Network liquidity tool released - Versioned Storage Service announced - Fuzz testing tool for Bitcoin nodes - Bitcoin Control Board components open-sourced Bitcoin Core 29.0 is the latest major version of the network’s predominate full node. Its release notes describe several significant improvements... Correction Last week’s newsletter story about SwiftSync contained several errors and confusing statements... 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!
Bitcoin Optech newsletter #349 is here: - describes a proposal for speeding up Bitcoin Core initial block download, with a proof-of-concept implementation that shows a roughly 5x speed up compared to Bitcoin Core’s defaults - recaps the "Stricter internal handling of invalid blocks " PR Review Meeting - Optech Newsletter #349 Recap on Riverside Sebastian Falbesoner posted to Delving Bitcoin a sample implementation and performance results for SwiftSync, an idea proposed by Ruben Somsen during a recent Bitcoin Core developers meeting and later posted to the mailing list... 'Add Fee rate Forecaster Manager' is a PR by ismaelsadeeq that upgrades the transaction fee forecasting (fee estimation) logic... 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!
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 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... Several conversations examined how Bitcoiners could respond to quantum computers becoming powerful enough to allow stealing bitcoins... Several conversations examined various aspects of soft forking in the OP_CHECKTEMPLATEVERIFY (CTV) and OP_CHECKSIGFROMSTACK (CSFS) opcodes... 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... 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... 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!
Earlier today, nprofile1qqsf2ds69dp2ympzhtpmdd46f3w2cnfkjphtpnaesf5xs8z95vqu2xqytd0r5 and @schmidty were joined by Sjors Provoost and Antoine Poinsot to discuss Newsletter #347: - Fee-Based Spam Prevention For Lightning - Testnets 3, Testnet 4 - Taproot annexes - BIP30, BIP34, witness commitments, and the block 1,983,702 problem - Malleating any 64-byte transactions - And more! Catch up:
Bitcoin Optech newsletter #347 is here: - describes upfront and hold fees in LN based on burnable outputs - summarizes discussion about testnets 3 and 4 - announces a plan to relay certain transactions containing taproot annexes - summarizes popular Q&A from Stack Exchange - Bitcoin Core 29.0rc2 - Optech Newsletter #347 Recap John Law posted to Delving Bitcoin the summary of a paper he’s written about a protocol nodes can use to charge two additional types of fees for forwarding payments... Sjors Provoost posted to the Bitcoin-Dev mailing list to ask whether anyone was still using testnet3 now that testnet4 has been available for about six months... Peter Todd announced to the Bitcoin-Dev mailing list his plan to update his Bitcoin Core-based node, Libre Relay, to begin relaying transactions containing taproot annexes if they follow particular rules... Selected Q&A from Bitcoin Stack Exchange: - Why is the witness commitment optional? - Can all consensus valid 64 byte transactions be (third party) malleated to change their size? - How long does it take for a transaction to propagate through the network? - Utility of longterm fee estimation - Why are two anchor outputs are used in the LN? - Why are there no BIPs in the 2xx range? - Why doesn’t Bech32 use the character “b”? - Bech32 error detection and correction reference implementation - How to safely spend/burn dust? - How is the refund transaction in Asymmetric Revocable Commitments constructed? - Which applications use ZMQ with Bitcoin Core? Bitcoin Core 29.0rc2 is a release candidate for the next major version of the network’s predominate full node. Please see the version 29 testing guide. 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!
Yesterday @npub1j5mp...sd5c and @schmidty 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:
Last week @npub1j5mp...sd5c and @schmidty were joined by Sindura Saraswathi, Christian Kümmerle, and Stéphan Vuylsteke to discuss Newsletter #345: - P2P traffic analysis - Research into single-path LN pathfinding - Probabilistic payments using different hash functions as an xor function - A Bitcoin Core PR Review Club on invalid blocks - Notarizing macOS and codesigning Bitcoin Core on Windows and macOS - and more… Catch up:
Bitcoin Optech newsletter #346 is here: - summarizes a discussion about LND’s updated dynamic feerate adjustment system - summarizes changes to services/client software - Bitcoin Core 29.0rc2 - Optech Newsletter #346 Recap Matt Morehouse posted to Delving Bitcoin a description of LND’s recently-rewritten sweeper system, which determines the feerates to use for onchain transactions (including RBF fee bumps)... Changes to services and client software: - Wally 1.4.0 released - Bitcoin Core Config Generator announced - A regtest development environment container - Explora transaction visualization tool - Hashpool v0.1 tagged - DMND launching pooled mining - Krux adds taproot and miniscript - Source-available secure element announced - Nunchuk launches Group Wallet - FROSTR protocol announced - Bark launches on signet - Cove Bitcoin wallet announced Bitcoin Core 29.0rc2 is a release candidate for the next major version of the network’s predominate full node. Bitcoin Optech will host an audio recap discussion of this newsletter streaming on Riverside.fm and X/Twitter Tuesday at 15:30 UTC. Join us to discuss or ask questions!
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 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... 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... 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... '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... 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!