schmidty

Fuzzamoto is a fuzz testing tool for Bitcoin full nodes. For the last year, Niklas Gögge (@Niklas) has been building Fuzzamoto with the goal of: “an external testing suite that gets as close as possible to taking production binaries as input and producing bugs as output” Part 1 of Brink’s blog series on Fuzzamoto provides an introduction of Fuzzamoto including its motivation, a design overview, and the first bugs found. https://brink.dev/blog/2026/01/07/fuzzamoto-introduction/ See our previous discussion with Niklas for further background on fuzz testing: https://brink.dev/blog/2023/07/14/fuzzing/

Its that time of the year again Bitcoin Optech's 2025 Year-in-Review 📝 a1c16e11…

Murch and I cover a lot of Bitcoin technical developments on the Bitcoin Optech podcast each week. But there is a lot going on in Bitcoin that we don’t cover. What are you curious about? Drop a question below and join us for a Twitter/X Space tomorrow and we will get to as many as we can. https://x.com/i/spaces/1OwxWeWXMoVGQ

As part of Brink's mission to ensure the safety and robustness of the open-source Bitcoin Core software, we recently sponsored an independent security audit of the Bitcoin Core codebase. This represents the first public, third-party audit of Bitcoin Core. https://brink.dev/blog/2025/11/19/bitcoin-core-security-a… The assessment was conducted by Quarkslab and was coordinated with the help of the Open Source Technology Improvement Fund (OSTIF). Funding was provided by Brink with the support of our donors, with technical collaboration from Brink engineer, Niklas Gögge, and Chaincode Labs engineer, Antoine Poinsot. Why Brink funded this work The project has a strong security track record, but it has never undergone an external security assessment. We wanted to provide an additional layer of assurance for developers, node operators, holders, and businesses who rely on Bitcoin Core every day What the audit involved The focus was on the most security-critical components of the software, including the peer-to-peer networking layer, mempool, chain management, and consensus logic and included: - Manual code review - Static and dynamic analysis - Advanced fuzz testing What the auditors found The auditors at Quarkslab reported no critical, high, or medium-severity issues. They identified two low-severity findings and thirteen informational recommendations, none of which were classified as security vulnerabilities under Bitcoin Core’s criteria. Funding independent reviews like this is just one way we help ensure Bitcoin doesn’t break and continues to serve the world as a secure, reliable monetary network. Independent review only strengthens that confidence. Thank you to Quarkslab, the OSTIF, Niklas, and Antoine for their work on this project. The full report is publicly available here: https://ostif.org/wp-content/uploads/2025/11/25-05-2133-R…

Meanwhile… The decade-long engineering efforts toward libsecp256k1, a minimal from scratch Bitcoin-specific library, result in an 800% speed up over OpenSSL while also: - removing a problematic dependency - avoiding side channel attacks - being fully deterministic Sebastian Falbesoner via https://bitcoinops.org/en/newsletters/2025/11/07/#compari…

“Where is the public roadmap for Bitcoin Core?” This sentiment from Zach is common and Ill give my own thoughts on it https://x.com/zachherbert/status/1976726178376696016 The subprojects that individual Bitcoin Core engineers contribute to reflect the project’s *software development priorities* which can include things like testing improvements, refactors, features, maintenance, or performance improvements. These software engineering efforts are distinct from the Bitcoin *protocol*, whose consensus rules change only through broad community agreement and network adoption, not by decisions made exclusively within the Bitcoin Core repository. If I were looking to derive a shorter term “public roadmap for Bitcoin Core” (again, the Bitcoin Core software, not Bitcoin protocol), there are a few places to look. **Working Groups** Contributors actively working on similar efforts form working groups to implement and review projects in Bitcoin Core. A list of the current working groups is on the Bitcoin Core Wiki: https://github.com/bitcoin-core/bitcoin-devwiki/wiki/Work… From here we can see interest in: Erlay, Fuzzing, Kernel, Benchmarking, Silent Payments, Cluster Mempool, Stratum v2, Multiprocess, QML GUI, and Net Split These working groups also provide updates at the weekly Bitcoin Core developer meetings on IRC: https://bitcoincore.org/en/meetings/ This is another place to see current work. **Tracking issues** Many subprojects within Bitcoin Core have a place to track a todo list of code changes that roll up into that project. Here are just a few examples (search the GitHub for “tracking issue” for more): Multiprocess - https://github.com/bitcoin/bitcoin/issues/28722 Mining interface - https://github.com/bitcoin/bitcoin/issues/33777 MuSig2 - https://github.com/bitcoin/bitcoin/issues/31246 Cluster mempool - https://github.com/bitcoin/bitcoin/issues/30289 Erlay - https://github.com/bitcoin/bitcoin/issues/30249 Bitcoin Kernel Library - https://github.com/bitcoin/bitcoin/issues/27587 SENDTEMPLATE - https://github.com/bitcoin/bitcoin/issues/33691 **Core Dev meetups** What developers discuss at recent in-person meetings is another data point. Here are transcripts from the October 2025 meeting - https://btctranscripts.com/bitcoin-core-dev-tech/2025-10 February 2025 meeting - https://btctranscripts.com/bitcoin-core-dev-tech/2025-02 **Merged PRs** As code changes are merged into the Bitcoin Core GitHub before the next release you can see precisely what will be in the upcoming release. These code changes include PRs related to projects above, but also more general changes unrelated to a particular project, like maintenance work, additional testing, one-off features, etc. https://github.com/bitcoin/bitcoin/pulls?q=is%3Apr+is%3Am… Likewise Optech has a weekly notable code segment that picks interesting code merges to cover: https://bitcoinops.org/ **Release Milestones** As Bitcoin Core progresses toward a new release, PRs can be tagged with a milestone representing that release. For example, here are the items tagged for the previous v30 release: https://github.com/bitcoin/bitcoin/pulls?q=is%3Apr+milest… And here are considerations for the v31 release: https://github.com/bitcoin/bitcoin/pulls?q=is%3Apr+milest… **TLDR, just tell me what will be in v31** Sorry, there isn’t a definitive authoritative answer for a decentralized open source project like this. But also in the spirit of decentralization, I can provide my own guesses of what might be in there. Kernel API - modular use of Bitcoin’s consensus and validation logic outside the full node MuSig2 (in wallet) - fee-efficient, privacy-preserving multi-signature support Cluster mempool - makes transaction relay and block assembly more efficient, predictable, and network reliability. ASMap - help diversify peer connections, strengthening network resilience against eclipse attacks Static builds - reproducible, portable binaries that enhance security, verifiability, and ease of deployment I’ll emphasize that while these projects took a ton of work to get where they are, there will also be a majority of PRs in v31 that will not be part of a “project”. They will simply be general improvements, bug fixes, and maintenance work (see https://x.com/bitschmidty/status/1976692672023667057 for examples)

Jameson Lopp and Tim Ruffing on quantum Steven Roose on the OP_TEMPLATEHASH soft fork bundle David Gumberg on compact block prefilling Lauren Shareshian from Block on mempool fee estimation 📝 dbfccc69…