Bitcoin Optech newsletter #404 is here: - announces the responsible disclosure of a vulnerability that could allow an attacker with sufficient proof-of-work to crash Bitcoin Core nodes - describes a draft BIP proposal for sharing the UTXO set over the P2P network - Optech Newsletter #405 Podcast https://bitcoinops.org/en/newsletters/2026/05/15/ Niklas Gögge posted to the Bitcoin-Dev mailing list disclosing CVE-2024-52911, a vulnerability affecting versions of Bitcoin Core after version 0.14.0 and before 29.0... https://bitcoinops.org/en/newsletters/2026/05/15/#bitcoin-core-script-interpreter-remote-crash-disclosure Fabian Jahr posted to the Bitcoin-Dev mailing list about a draft BIP for sharing the UTXO set over the P2P layer... https://bitcoinops.org/en/newsletters/2026/05/15/#bip-proposal-for-utxo-set-sharing-over-p2p-network Bitcoin Optech will host an audio recap discussion of this newsletter streaming live on X/Twitter Tuesday at 16:30 UTC.

Bitcoin Optech newsletter #404 is here: - describes possible solutions to node fingerprinting - links to discussion of using public fraud proofs to improve incentives around just-in-time channels - Optech Newsletter #404 Podcast https://bitcoinops.org/en/newsletters/2026/05/08/ Naiyoma posted to Delving Bitcoin about possible solutions to the node fingerprinting issue that uses the addr message timestamp to identify the same node on multiple networks... https://bitcoinops.org/en/newsletters/2026/05/08/#possible-solutions-to-node-fingerprinting Thomas Voegtlin posted to Delving Bitcoin about a new proposal for improving the game theory behind just-in-time (JIT) channels by using public fraud proofs to demonstrate that an LSP is misbehaving... https://bitcoinops.org/en/newsletters/2026/05/08/#public-fraud-proof-for-just-in-time-channels Bitcoin Optech will host an audio recap discussion of this newsletter streaming live on X/Twitter Tuesday at 16:30 UTC.

Toby Sharp joined Optech to discuss Newsletter #402: - Hornet Node's declarative executable specification of Bitcoin consensus rules - Onion message jamming in the Lightning Network - Selected Q&A from the Bitcoin Stack Exchange - And more You can listen on our website: https://bitcoinops.org/en/podcast/2026/04/28/ Spotify: https://open.spotify.com/episode/6FMbkM46QhnGJYh064JhwA Apple Podcasts: https://podcasts.apple.com/us/podcast/bitcoin-optech-newsletter-402-recap/id1674626983?i=1000765658933

Bitcoin Optech newsletter #403 is here: - describes research around using binary fuse filters as an alternative to the GCS used in compact block filters - links to an idea for post-quantum HD wallets with fallback SPHINCS keys - summarizes discussion of a post-quantum output type - examines a proposal to embed post-quantum keys in tapscript without consensus changes - summarizes results of a BIP54 demonstration of slow blocks on signet - links to work on post-quantum BIP86 recovery using zk-STARK proofs of BIP32 seeds - Optech Newsletter #403 Podcast https://bitcoinops.org/en/newsletters/2026/05/01/ Csaba Purszki posted to Delving Bitcoin his research on finding a better alternative to Golomb-Rice Coded Sets (GCS) used for compact block filters as defined in BIP158... https://bitcoinops.org/en/newsletters/2026/05/01/#binary-fuse-filters-as-an-alternative-to-bip158-s-gcs In a post on the Bitcoin-Dev mailing list, Conduition described a design for post-quantum BIP32 congruent hierarchical deterministic wallets with fallback SPHINCS keys... https://bitcoinops.org/en/newsletters/2026/05/01/#post-quantum-hd-wallets-with-fallback-sphincs-keys Antoine Poinsot wrote to the Bitcoin-Dev mailing list defending a plain post-quantum output type (as opposed to a P2TR-like output type which allows quantum-vulnerable key spending to be disabled by a later soft fork)... https://bitcoinops.org/en/newsletters/2026/05/01/#discussion-of-a-post-quantum-output-type Daniel Buchner sent a proposal to the Bitcoin-Dev mailing list which describes a potential path to enabling flexible post-quantum wallet designs without fully describing the signature validation parameters... https://bitcoinops.org/en/newsletters/2026/05/01/#proposal-to-embed-post-quantum-keys-in-tapscript-without-consensus-changes On Delving Bitcoin, Antoine Poinsot wrote about a demonstration of the types of slow-to-validate blocks that BIP54 (consensus cleanup) prevents... https://bitcoinops.org/en/newsletters/2026/05/01/#bip54-demonstration-of-slow-blocks-on-signet Olaoluwa Osuntokun (roasbeef) posted on the Bitcoin-Dev mailing list his project to demonstrate zk-STARK recovery of quantum-vulnerable coins secured by keys derived using BIP32... https://bitcoinops.org/en/newsletters/2026/05/01/#post-quantum-bip86-recovery-using-zk-stark-proofs-of-bip32-seeds Bitcoin Optech will host an audio recap discussion of this newsletter streaming live on X/Twitter Tuesday at 16:30 UTC.

Bitcoin Optech newsletter #402 is here: - describes work on a declarative executable specification of consensus rules - summarizes a discussion about onion message jamming in the Lightning Network - summarizes popular Q&A from Stack Exchange - Optech Newsletter #402 Podcast https://bitcoinops.org/en/newsletters/2026/04/24/ Toby Sharp posted to Delving Bitcoin and the Bitcoin-Dev mailing list an update on the Hornet node project... https://bitcoinops.org/en/newsletters/2026/04/24/#hornet-node-s-declarative-executable-specification-of-bitcoin-consensus-rules Erick Cestari posted to Delving Bitcoin about the onion message jamming problem affecting the Lightning Network... https://bitcoinops.org/en/newsletters/2026/04/24/#onion-message-jamming-in-the-lightning-network Selected Q&A from Bitcoin Stack Exchange - Why did BIP342 replace CHECKMULTISIG with a new opcode, instead of just removing FindAndDelete from it? - Does SIGHASH_ANYPREVOUT commit to the tapleaf hash or the full taproot merkle path? - What does the BIP86 tweak guarantee in a MuSig2 Lightning channel, beyond address format? https://bitcoinops.org/en/newsletters/2026/04/24/#selected-qa-from-bitcoin-stack-exchange Bitcoin Optech will host an audio recap discussion of this newsletter streaming live on X/Twitter Tuesday at 16:30 UTC.

Remix7531 and Luis Schwab joined Optech to discuss Newsletter #401: - Nested MuSig2 for k-of-n multisignature Lightning nodes - Formal verification of secp256k1 modular scalar multiplication - Changes to services and client software including Utreexo software and others - And more You can listen on our website: https://bitcoinops.org/en/podcast/2026/04/21/ Spotify: https://open.spotify.com/episode/4A7d3nR1mDvGi1zPA6pZZC Apple Podcasts: https://podcasts.apple.com/us/podcast/bitcoin-optech-newsletter-401-recap/id1674626983?i=1000763037535

Bitcoin Optech newsletter #401 is here: - describes an idea for nested MuSig2 Lightning nodes - summarizes a project formally verifying secp256k1’s modular scalar multiplication - summarizes changes to services/client software - Optech Newsletter #401 Podcast https://bitcoinops.org/en/newsletters/2026/04/17/ ZmnSCPxj posted to Delving Bitcoin about the idea to create k-of-n multisignature Lightning nodes by leveraging nested MuSig2... https://bitcoinops.org/en/newsletters/2026/04/17/#discussion-of-using-nested-musig2-in-the-lightning-network Remix7531 posted to the Bitcoin-Dev mailing list about formally verifying secp256k1’s modular scalar multiplication... https://bitcoinops.org/en/newsletters/2026/04/17/#formal-verification-of-secp256k1-modular-scalar-multiplication Changes to services and client software: - Coldcard 6.5.0 adds MuSig2 and miniscript - Frigate 1.4.0 released - Bitcoin Backbone updates - Utreexod 0.5 released https://bitcoinops.org/en/newsletters/2026/04/17/#changes-to-services-and-client-software Bitcoin Optech will host an audio recap discussion of this newsletter streaming live on X/Twitter Tuesday at 16:30 UTC.