Brink is excited to announce that Martin Zumsande has (re)joined Brink to continue his work on Bitcoin Core including P2P networking, validation, testing, and review! Martin will focus on researching address relay propagation, improving block download reliability, closing a privacy leak in wallet transaction rebroadcast, and expanding validation fuzz testing, in addition to continued code review.

Welcoming back Martin Zumsande

Martin Zumsande has joined Brink to continue his work on Bitcoin Core

Reproducing rare bugs found during fuzz testing is hard because software can run slightly differently every time. Bedrock is a hypervisor that controls that randomness, so given the same inputs a program runs identically on every execution. Niklas outlines an approach and a solution, bedrock, for this problem of determinism. He focuses on the challenge of emulating time and pausing a VM at an exact instruction count, something CPUs aren't designed to do.

Introducing Bedrock: A Deterministic Hypervisor

Bedrock: A general solution to achieving full determinism in software testing by building a deterministic hypervisor to emulate time and trigger vi...

The result is an open source tool, bedrock: an experimental hypervisor purpose-built for deterministic software testing.

GitHub

GitHub - oss-garage/bedrock: Experimental Hypervisor Purpose-Built for Deterministic Software Testing

Experimental Hypervisor Purpose-Built for Deterministic Software Testing - oss-garage/bedrock

Toby Sharp joined Brink engineers to present Hornet, an executable specification for Bitcoin consensus. In his presentation, he discussed: * “The code is the spec” * How Hornet differs from libbitcoinkernel * Properties of a good specification * The 35 semantic rules that define block validity * A declarative C++ implementation of the rules * A custom UTXO database designed for Bitcoin * Approaches to block validation * Ideas of a domain specific language (DSL) for consensus * Differential and adversarial testing * Q&A with the audience

Toby Sharp on Hornet, an executable specification for Bitcoin consensus

Toby Sharp presents Hornet, an executable specification for Bitcoin consensus.

Brink has always funded remote engineers, since our inception. Our London office is there for those who want an in-person space to collaborate, but it's always been optional. In fact, most of the engineers we've funded over the years have worked remotely. The mix shifts over time. Right now it's 5 in office and 4 remote. Wherever you are and whatever lets you do your best work on Bitcoin is what we're here to support.

Two research interns, Dongjia Zhang and Stratos, recently wrapped up their 3 months of work on fuzz testing for Bitcoin Core. Under the guidance of Niklas Gögge, each conducted independent research & experimentation on Fuzzamoto. Dongjia is a Ph.D. researcher specializing in software security and fuzzing, and is the maintainer of LibAFL, a popular fuzzing framework. His extensive background in fuzzing made him well suited to contribute to several of Fuzzamoto’s engineering and testing challenges. Stratos is a vulnerability researcher and approached Bitcoin Core security from a systems and protocol security perspective. Both engineers made meaningful contributions to Fuzzamoto. Their work extended protocol support, improved benchmarking infrastructure, scaled coverage analysis, and broadened target coverage for the testing platform. Read more on their achievements during the internship:

Fuzz Testing Research Interns: Dongjia Zhang and Stratos

A summary of Dongjia Zhang and Stratos

Thank you Dongjia and Stratos for your contributions!

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

Bitcoin Optech

Bitcoin Optech Newsletter #379

This week’s newsletter shares an analysis comparing the historical performance of the OpenSSL and libsecp256k1 libraries. Also included are our r...

The topic of non-developer contributions to Bitcoin and Bitcoin Core came up in a thread the other day. So I wanted to elevate this list, in case people are interested. Ways to contribute other than code: Education / Outreach Optech Conferences Saving Satoshi Fundraising Bitdevs User feedback Reproducing issues Priorities? Security Dependency auditing CVE disclosure Mailing list Pen testing Dev Tooling CI Signet Fuzzing Drahtbot Corecheck,dev Bitcoin dev wiki Mentoring Developer hubs Review clubs Release Process Testing guide Building binaries Signing binaries translations Packaging for distro Monitoring b10c stuff etc Standardization BIPs Bolts etc Events Coredev Online communication channels Mailing list Delving IRC Twitter / etc Stack exchange

Bitcoin Core

Bitcoin

Bitcoin

Backups of stuff Dev Infrastructure Fuzzing Devops stuff Dns seeds User feedback Outward Talk to miners? Exchanges? Surveys Research BRW Janitor work Reproducing Other items listed: Coredev conference BIPs (review, reading) Stack exchange CI Fuzzer machines Devops Monitoring

Bitcoin Core

Bitcoin

Bitcoin

maintaining/hosting Signet / inquisition Utilities for interacting with Bitcoin (Core) Educational stuff like saving satoshi Delving Mailing list Backup of delving/mailing list/github comments IRC and logs Drahtbot / meetingbot Bitcoinacks (?) Fundraising Developer hubs Review clubs Technical talks / podcasts / outreach Bitdevs Deterministic builds (running) Dns seed Dependency auditing/pruning Architecture CI doesn’t account for Reproducing issues Moderation of github Research Week Twitter threads Translations Security Security mailing list CVE management / disclosure etc Pen testing

corecheck - Test Coverage

Core dev wiki Bitcoin wiki Summaries of communal knowledge Optech Release packaging for distros Janitoring old issues/PRs BOSS program Summer of Bitcoin Original:

Non-development Contributions

Eric Voskuil joined Bitcoin engineers to discuss architectural and performance differences between libbitcoin and Bitcoin Core: - libbitcoin’s history/latest updates - libbitcoin architecture - Initial block download (IBD) performance - IBD workflow - SwiftSync - Q&A Watch the 90 minute discussion:

Eric Voskuil on Bitcoin Core

Eric Voskuil contrasts UTXO approaches in libbitcoin and Bitcoin Core.

There is a lot going on in the OP_RETURN debate, but I definitely agree with this: "What the OP_RETURN debate has demonstrated is that Bitcoin Core and the Bitcoin technical community have not done a good job communicating their value – not to mention the rationale behind their decisions – to the average bitcoin user." https://blockspace.media/insight/op_return-debate-the-influencers-vs-the-devs/ The Bitcoin Core developers have produced artifacts and content on these matters already, but those of us closely observing need to do a better job of disseminating that information to a broader set of Bitcoin ecosystem participants. "The single biggest problem in communication is the illusion that it has taken place." I need to do better.

Is there a way to stream video via RTMP to nostr?

Which way, quantum Bitcoiner?

Consensus Cleanup soft fork BIP draft dropped https://github.com/bitcoin/bips/pull/1800

If you’ve thought about contributing to Bitcoin open source, I cannot recommend enough applying for the ‘Start your career in Bitcoin open source’ program. The lowest risk path to contribute to the projects you use, know, and love: Bitcoin Core, Lightning, BDK, rust-bitcoin, and more It's a 2 month, online program that is completely FREE (thank you, Chaincode) Don't wait another year. Don't wait to watch another couple Bitcoin development YT videos Get in the arena. Help build magic internet money Applications close December 31 Agenda: Week 0: RPC Scavenger Hunt Week 1: Build a wallet Week 2: Wallet management Week 3: P2P & Mining Week 4: Lightning Bring a proof of concept to life Explore the ₿OSS ecosystem Meet ₿OSS maintainers Choose a ₿OSS project and provide value Get coaching on the next step

₿OSS Challenge

₿OSS Challenge - start your career in bitcoin open source

I get the impression that this is pretty common for Optech readers. Would some periodic less-technical “Optech decoded” or “Optech translated” summary be helpful?

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