Oddbean

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