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Bitcoin Optech
_@bitcoinops.org
npub1hkuk...432p
We provide weekly newsletters, workshops, case studies, and research for the #Bitcoin community.
Bitcoin Optech newsletter #294 is here: - announces a project to create a BIP324 proxy for light clients - summarizes discussion about a proposed BTC Lisp language - summarizes changes to services/client software - adds a Kindred replace by fee topic - Optech #294 Recap Sebastian Falbesoner posted to Delving Bitcoin to announce a TCP proxy for translating between the version 1 (v1) Bitcoin P2P protocol and the v2 protocol defined in BIP324. This is especially intended to allow light client wallets written for v1 to take advantage of v2’s traffic encryption... Anthony Towns posted to Delving Bitcoin about his experiments over the past couple of years creating a variant of the Lisp language for Bitcoin, called BTC Lisp. See Newsletters #293 and #191 for previous discussions... Changes to services and client software: - BitGo adds RBF support - Phoenix Wallet v2.2.0 released - Bitkey hardware signing device released - Envoy v1.6.0 released - VLS v0.11.0 released - Portal hardware signing device announced - Braiins mining pool adds Lightning support - Ledger Bitcoin App 2.2.0 released Kindred replace by fee is the ability for a transaction to replace a related transaction in the mempool even if there’s no conflict between the two transactions... Bitcoin Optech will host an audio recap discussion of this newsletter with special guests Sebastian Falbesoner, Anthony Towns, and Russell O’Connor on Twitter Spaces Thursday at 14:30 UTC. Join us to discuss or ask questions! https://twitter.com/i/spaces/1ZkKzjEzkjyKv
Bitcoin Optech newsletter #293 is here: - summarizes a post about trustless onchain betting for potential soft forks - links to a detailed overview of Chia Lisp for Bitcoiners - recaps the "Re enable OP_CAT" PR Review Meeting - Core Lightning v24.02.1, Bitcoin Core 26.1rc1, Bitcoin Core 27.0rc1 release candidates ZmnSCPxj posted to Delving Bitcoin a protocol for giving control over a UTXO to a party that correctly predicts whether or not a particular soft fork will activate... Anthony Towns posted to Delving Bitcoin a detailed overview of the Lisp variant used by the Chia cryptocurrency... 'Re enable OP_CAT' is a PR by Armin Sabouri (GitHub 0xBEEFCAF3) that reintroduces the OP_CAT opcode but only on signet Bitcoin Inquisition and only for tapscript (taproot script)... Bitcoin Core 27.0rc1 is a release candidate for the next major version of the network’s predominant full node implementation. Bitcoin Optech will host an audio recap discussion of this newsletter on Twitter Spaces Thursday at 14:00 UTC (new time!). Join us to discuss or ask questions! https://twitter.com/i/spaces/1ynKOyNnAprJR
Bitcoin Optech newsletter #292 is here: - summarizes a discussion about updating the specification for BIP21 bitcoin: URIs - describes a proposal to manage multiple concurrent MuSig2 signing sessions with a minimum of state - links to a thread about adding editors for the BIPs repository - discusses a set of tools that allow quickly porting the Bitcoin Core GitHub project to a self-hosted GitLab project - Optech Newsletter #292 Recap on Twitter Spaces Josie Baker posted to Delving Bitcoin to discuss how BIP21 URIs are specified to be used, how they’re used today, and how they can be used in the future... Salvatore Ingala posted to Delving Bitcoin about minimizing the amount of state needed to perform multiple MuSig2 signing sessions in parallel... Ava Chow posted to the Bitcoin-Dev mailing list to suggest the addition of BIP editors to help the current editor... Fabian Jahr posted to Delving Bitcoin about maintaining a backup of the Bitcoin Core project’s GitHub account on a self-hosted GitLab instance. In case the project ever needed to leave GitHub suddenly, this would make all existing issues and pull requests accessible on GitLab within a short amount of time, allowing work to continue with only a brief interruption... Bitcoin Optech will host an audio recap discussion of this newsletter with special guests Josie Baker, Salvatore Ingala, and Fabian Jahr on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions! https://twitter.com/i/spaces/1mnxepjZboAJX
Bitcoin Optech newsletter #291 is here: - describes a proposed contract for trustless miner feerate futures, - links to a coin selection algorithm for LN nodes providing dual funding liquidity - details a prototype for a vault using OP_CAT - discusses sending and receiving ecash using LN and ZKCPs - summarizes popular Q&A from Stack Exchange - adds an Ecash topic - Optech Newsletter #291 Recap on Twitter Spaces ZmnSCPxj posted to Delving Bitcoin a set of scripts that will allow two parties to conditionally pay each other based on the marginal feerate to include a transaction in a future block... Richard Myers posted to Delving Bitcoin about creating a coin selection algorithm that is optimized for LN nodes offering liquidity via liquidity advertisements... Developer Rijndael posted to Delving Bitcoin about a Rust-language proof-of-concept implementation he’s written for a vault that only depends on the current consensus rules plus the proposed OP_CAT opcode... Anthony Towns posted to Delving Bitcoin about linking “ecash mints to the lightning network without losing ecash’s anonymity or adding any additional trust”... Selected Q&A from Bitcoin Stack Exchange: - Why can’t nodes have the relay option to disallow certain transaction types? - What is the circular dependency in signing a chain of unconfirmed transactions? - How does Ocean’s TIDES payout scheme work? - What data does the Bitcoin Core wallet search for during a blockchain rescan? - How does transaction rebroadcasting for watch-only wallets work? Ecash is a type of centralized digital currency that uses blind signatures to prevent the centralized controlling party (the mint) from knowing the balance of any particular user or from learning which users were involved in any transactions... Bitcoin Optech will host an audio recap discussion of this newsletter with special guests Richard Myers and Rijndael on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions! https://twitter.com/i/spaces/1RDGllLMreoGL
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 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... 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... 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... 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... 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... 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 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
Bitcoin Optech newsletter #289 is here: - summarizes ideas for relay enhancements after cluster mempool is deployed - describes research into the topologies and sizes of LN-style anchor outputs in 2023 - announces a new host for the Bitcoin-Dev mailing list - encourages readers to celebrate I Love Free Software Day by thanking free software contributors - recaps the "Add maxfeerate and maxburnamount args to submitpackage" PR Review Meeting - Newsletter #289 Recap Gregory Sanders posted to Delving Bitcoin several ideas for allowing individual transactions to opt-in to certain mempool policies after cluster mempool support has been fully implemented, tested, and deployed... Suhas Daftuar posted to Delving Bitcoin about his research into the idea of automatically applying v3 transaction relay policy to anchors-style LN commitment and fee-bumping transactions... The Bitcoin protocol development discussion mailing list is now hosted on a new server with a new email address. Everyone who wishes to continue receiving posts needs to resubscribe... Every year on February 14th, organizations such as FSF and FSFE encourage users of free and open source software (FOSS) to “reach out and say ‘Thank you!’ to all the people maintaining and contributing to Free Software”... 'Add maxfeerate and maxburnamount args to submitpackage' is a PR by Greg Sanders (GitHub instagibbs) that adds functionality to the submitpackage RPC that is already present in the single-transaction RPCs sendrawtransaction and testmempoolaccept... Bitcoin Optech will host an audio recap discussion of this newsletter with special guest Gregory Sanders on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions! https://twitter.com/i/spaces/1DXxyjlmXrbKM
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 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... 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... 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... 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... 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. 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
Bitcoin Optech newsletter #287 is here: - describes a proposal to allow replacement of v3 transactions using RBF rules to ease the transition to cluster mempool - summarizes an argument against OP_CHECKTEMPLATEVERIFY based on it commonly requiring exogenous fees - summarizes popular Q&A from Stack Exchange - adds a Fee sourcing topic - adds a Simple taproot channels topic - Optech Newsletter #287 Recap on Twitter Spaces Gloria Zhao posted to Delving Bitcoin about allowing a transaction to replace a related transaction in the mempool even if there’s no conflict between the two transactions... Peter Todd posted to the Bitcoin-Dev mailing list an adaptation of his argument against exogenous fees (see Newsletter #284) applied to the OP_CHECKTEMPLATEVERIFY proposal... Selected Q&A from Bitcoin Stack Exchange: - How does block synchronization work in Bitcoin Core today? - How does headers-first prevent disk-fill attack? - Is BIP324 v2transport redundant on Tor and I2P connections? - What’s a rule of thumb for setting the maximum number of connections? - Why isn’t the upper bound (+2h) on the block timestamp set as a consensus rule? - Sigop count and its influence on transaction selection? Fee sourcing refers to the decisions made by designers of committed transactions (such as presigned transactions) about what sources of funds they’ll use for paying transaction fees... Simple taproot channels are LND funding and commitment transactions that use taproot (P2TR) with support for MuSig2 scriptless multisignature signing when both parties are cooperating... Bitcoin Optech will host an audio recap discussion of this newsletter with special guests Gloria Zhao and Brandon Black on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions! https://twitter.com/i/spaces/1lPJqblBqMexb
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 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... 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... 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... 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... Tom Briar posted to the Bitcoin-Dev mailing list an updated draft specification and proposed implementation of compressed Bitcoin transactions... Gregory Sanders posted to Delving Bitcoin to discuss concerns about ephemeral anchor outputs that contain more than 0 satoshis... 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... 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
Bitcoin Optech newsletter #284 is here: - summarizes discussion about LN anchors and elements of the v3 transaction relay proposal - announces a research implementation of LN-Symmetry - recaps the "Nuke adjusted time (attempt 2)" PR Review Meeting - adds an Out-of-band fees topic - Optech Newsletter #284 Recap on Twitter Spaces Antoine Poinsot posted to Delving Bitcoin to foster discussion about the proposals for v3 transaction relay policy and ephemeral anchors. We’ve divided the discussion into several parts... Gregory Sanders posted to Delving Bitcoin about a proof-of-concept implementation he made of the LN-Symmetry protocol (originally called eltoo) using a software fork of Core Lightning... Nuke adjusted time (attempt 2) is a PR by Niklas Gögge that modifies a block validity check related to the block’s timestamp... Out-of-band fees are payments made directly to a specific miner (or group of miners) in exchange for confirming one or more transactions. They can be contrasted with standard in-band fees that are paid using the fee implied by the difference in a transaction’s input and output value... Bitcoin Optech will host an audio recap discussion of this newsletter on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions! https://twitter.com/i/spaces/1mnxepPqnmQJX
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 Niklas Gögge posted to Delving Bitcoin about two vulnerabilities he had previously responsibly disclosed, which led to fixed versions of LND being released... 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... 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... 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)... 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... 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... 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... 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)... 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... 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
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 This year saw much discussion and many proposals around potential soft forks... Optech reported on three significant security vulnerabilities this year... Optech covered major releases of popular infrastructure projects throughout the year... 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... 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
Bitcoin Optech newsletter #281 is here: - summarizes a discussion about griefing liquidity advertisements - summarizes changes to services/client software - summarizes popular Q&A from Stack Exchange - Optech Newsletter #281 Recap on Twitter Spaces Bastien Teinturier posted to the Lightning-Dev mailing list about a potential problem with timelocks on dual-funded channels created from liquidity advertisements... Changes to services and client software: - Stratum v2 mining pool launches - Bitcoin network simulation tool warnet announced - Payjoin client for Bitcoin Core released - Call for community block arrival timestamps - Envoy 1.4 released - BBQr encoding scheme announced - Zeus v0.8.0 released Selected Q&A from Bitcoin Stack Exchange: - What are all the rules related to CPFP fee bumping? - How is the total number of RBF replaced transactions calculated? - What types of RBF exist and which one does Bitcoin Core support and use by default? - What is the Block 1,983,702 Problem? - What are hash functions used for in bitcoin? 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/1YpJkwPgyBjJj
Bitcoin Optech newsletter #279 is here: - summarizes an update to the liquidity advertisements specification - summarizes popular Q&A from Stack Exchange - Bitcoin Core 26.0rc3 - Optech Newsletter #279 Recap on Twitter Spaces Lisa Neigut posted to the Lightning-Dev mailing list to announce an update to the specification for liquidity advertisements... Selected Q&A from Bitcoin Stack Exchange: - Is Schnorr a multisignature interactive scheme? - Is it advisable to operate a release candidate full node on mainnet? - What is the relation between nLockTime and nSequence? - What would happen if we provide to OP_CHECKMULTISIG more than threshold number (m) of signatures? - What is “(mempool) policy”? - What does Pay to Contract (P2C) mean? - Can a non-segwit transaction be serialized in the segwit format? Bitcoin Core 26.0rc3 is a release candidate for the next major version of the predominant full-node implementation. There’s a testing guide available. Bitcoin Optech will host an audio recap discussion of this newsletter with special guest Lisa Neigut on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions! https://twitter.com/i/spaces/1OwGWYZdqaWxQ
Bitcoin Optech newsletter #278 is here: - describes a proposal to allow retrieval of LN offers using specific DNS addresses similar to lightning addresses - summarizes changes to services/client software - Bitcoin Core 26.0rc2 release candidate - Optech Newsletter #278 Recap on Twitter Spaces Bastien Teinturier posted to the Lightning-Dev mailing list about creating email-style addresses for LN users in a way that takes advantage of the features of the offers protocol... Changes to services and client software: - BitMask Wallet 0.6.3 released - Opcode documentation website announced - Athena Bitcoin adds Lightning support - Blixt v0.6.9 released - Durabit whitepaper announced - BitStream whitepaper announced - BitVM proof of concepts - Bitkit adds taproot send support Bitcoin Core 26.0rc2 is a release candidate for the next major version of the predominant full-node implementation. There’s a testing guide available. Bitcoin Optech will host an audio recap discussion of this newsletter with special guests Dave Harding, Bastien Teinturier, and Robin Linus on Twitter Spaces today (Wednesday) at 15:00 UTC. Join us to discuss or ask questions! https://twitter.com/i/spaces/1ypKdkaaXDvxW
Bitcoin Optech newsletter #277 is here: - describes an update to the proposal for ephemeral anchors - includes a contributed field report that outlines miniscript's ecosystem adoption - provides Bitcoin Core 26.0rc2 testing materials - Optech Newsletter #277 Recap on Twitter Spaces Gregory Sanders posted to the Delving Bitcoin forum about a tweak to the ephemeral anchors proposal. That proposal would allow transactions to include a zero-value output with an anyone-can-spend output script... Field Report: A Miniscript Journey Antoine Poinsot from Wizardsardine describes their perspectives on miniscript adoption Bitcoin Core 26.0rc2 is a release candidate for the next major version of the predominant full node implementation. There’s a testing guide and a scheduled meeting of the Bitcoin Core PR Review Club dedicated to testing on 15 November 2023. Bitcoin Optech will host an audio recap discussion of this newsletter with special guests Dave Harding, Gregory Sanders, Antoine Poinsot, and Max Edwards on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions! https://twitter.com/i/spaces/1RDGlljdDeOGL
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 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... 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... '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... 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. 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
Bitcoin Optech newsletter #275 is here: - follows up on several recent discussions about proposed changes to Bitcoin’s scripting language - LDK 0.0.118, Rust Bitcoin 0.31.1 releases There were several replies on the Bitcoin-Dev mailing list to proposed scripting change discussions we’ve previously covered. Anthony Towns compares Rusty Russell’s approach to other approaches specifically for covenant-based vaults and finds it unappealing. Several people replied to Ethan Heilman’s post announcing a proposed BIP for OP_CAT... Bitcoin Optech will host an audio recap discussion of this newsletter on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions! https://twitter.com/i/spaces/1PlKQDwepbqxE
Bitcoin Optech newsletter #274 is here: - describes the replacement cycling attack against HTLCs used in LN and other systems, examines the mitigations deployed, and summarizes proposals for additional mitigations - notes a bug affecting a Bitcoin Core RPC - describes research into covenants with minimal changes to Bitcoin Script - announces a proposed BIP for an OP_CAT opcode - summarizes popular Q&A from Stack Exchange - Optech Newsletter #274 Recap on Twitter Spaces As briefly mentioned in last week’s newsletter, Antoine Riard posted to the Bitcoin-Dev and Lightning-Dev mailing lists about a responsibly disclosed vulnerability affecting all LN implementations. It’s possible to use transaction replacement to remove one or more inputs of a multi-input transaction from node mempools... Several mitigations have been deployed by LN implementations for replacement cycling... There have been over 40 separate posts made to the Bitcoin-Dev and Lightning-Dev mailing lists in response to the disclosure of the replacement cycling attack. Suggested responses included proposed additional mitigations... Fabian Jahr posted to the Bitcoin-Dev mailing list to announce that a bug had been discovered in Bitcoin Core’s calculation of the hash of the current UTXO set... Rusty Russell posted to the Bitcoin-Dev mailing list a link to some research he has performed about using a few simple new opcodes to allow a script being executed in a transaction to inspect the output scripts being paid in that same transaction, a powerful form of introspection... Ethan Heilman posted to the Bitcoin-Dev mailing list a proposed BIP to add an OP_CAT opcode to tapscript... Selected Q&A from Bitcoin Stack Exchange: - How does the Branch and Bound coin selection algorithm work? - Why is each transaction broadcast twice in the Bitcoin network? - Why are OP_MUL and OP_DIV disabled in Bitcoin? - Why are hashSequence and hashPrevouts computed separately? - Why does Miniscript add an extra size check for hash preimage comparisons? - How can the next block fee be less than the mempool purging fee rate? Bitcoin Core 26.0rc1 is a release candidate for the next major version of the predominant full node implementation... Bitcoin Optech will host an audio recap discussion of this newsletter with special guests Fabian Jahr and Ethan Heilman on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions! https://twitter.com/i/spaces/1rmxPMZzbYQKN
Bitcoin Optech newsletter #273 is here: - mentions a recent security disclosure affecting LN users - describes a paper about making payments contingent on the result of running arbitrary programs - announces a proposed BIP to add fields to PSBTs for MuSig2 - summarizes changes to services/client software - Bitcoin Core 24.2rc2 and Bitcoin Core 25.1rc1 release candidates - Optech Newsletter #273 Recap on Twitter Spaces Antoine Riard posted to the Bitcoin-Dev and Lightning-Dev mailing lists the full disclosure of an issue he had previously responsibly disclosed to developers working on the Bitcoin protocol and various popular LN implementations... Robin Linus posted to the Bitcoin-Dev mailing list a paper he’s written about BitVM, a combination of methods that allows bitcoins to be paid to someone who successfully proves that an arbitrary program executed successfully. Notably, this is possible on Bitcoin today—no consensus change is required... Andrew Chow posted to the Bitcoin-Dev mailing list with a draft BIP, partly based on prior work by Sanket Kanjalkar, for adding several fields to all versions of PSBTs for the “keys, public nonces, and partial signatures produced with MuSig2.” Bitcoin Core 24.2rc2 and Bitcoin Core 25.1rc1 are release candidates for maintenance versions of Bitcoin Core. Bitcoin Optech will host an audio recap discussion of this newsletter with special guests Robin Linus and Antoine Poinsot on Twitter Spaces Thursday at 15:00 UTC. Join us to discuss or ask questions! https://twitter.com/i/spaces/1vAGRvZRgrvGl