OpenSats Work-Log 8

This is a copy of the 8th work-log I sent to OpenSats for my LTS grant.

Bitcoin Network Monitoring with b10c: SLP707

In this episode, Stephan Livera and I discusses my work in the Bitcoin ecosystem, focusing on the importance of censorship resistance, the role of …

Monitoring Bitcoin’s P2P network: Insights from the peer-observer Project

I presented about “Monitoring Bitcoin’s P2P network: Insights from the peer-observer Project” at the Chaincode Labs Bitcoin Research Day …

OpenSats Work-Log 7

This is a copy of the 7th work-log I sent to OpenSats for my LTS grant.

Support from LocalhostResearch for peer-observer

Localhost Research supported my peer-observer project by sponsoring three servers for a demo instance, which can be found on demo.peer.observer. …

OpenSats Work-Log 6

This is a copy of the 6th work-log I sent to OpenSats for my LTS grant.

peer-observer: A tool and infrastructure for monitoring the Bitcoin P2P network for attacks and anomalies

Over the past few years, I’ve been working on monitoring tools for the Bitcoin network. One of these projects is peer-observer: A tool and …

Notes on 'DoS due to inv-to-send sets growing too large' from May 2023

In October 2024, the Bitcoin Core project disclosed a Denial-of-Service due to inv-to-send sets growing too large, which I authored, for Bitcoin Core …

peer-observer: A tool and infrastructure for monitoring the Bitcoin P2P network for attacks and anomalies

I presented about my peer-observer project during the BTC Prague dev/hack/day 2025.

OpenSats Work-Log 5

This is a copy of the 5th work-log I sent to OpenSats for my LTS grant.

Bitcoin Mining Centralization in 2025

This post explores Bitcoin Mining Centralization in 2025 by looking at the hashrate share of the current five biggest mining pools. It presents a …

Invalid mining jobs by AntPool & friends during forks

Looking deeper into @boerst’s recent observation about invalid mining jobs by AntPool & friends to discuss his hypothesis about …

OpenSats Work-Log 4

This is a copy of the 4th work-log I sent to OpenSats for my LTS grant.

Fifteen OFAC-sanctioned transactions missing from blocks

My miningpool-observer project aims to detect when Bitcoin mining pools are not mining transactions they could have been mining. Over the past few …

OpenSats Work-Log 3

This is a copy of the 3rd work-log I sent to OpenSats for my LTS grant.

Episode 6: Discussing Pre-25.0 Bitcoin Core Vulnerability Disclosures

I joined Gloria and Niklas on the brink.dev podcast to talk about the recently disclosed Bitcoin Core pre-25.0 vulnerabilities.

Block Template Similarities between Mining Pools

Different mining pools sending out the same or a similar block template to miners is an indicator for proxy pooling. Knowing about proxy pools is …

Monitoring Bitcoin P2P network attacks and anomalies with eBPF and USDT tracepoints

I spoke at the eBPF Summit 2024 about how I’m using eBPF and the USDT tracepoints in Bitcoin Core to extract P2P network events to use them for, …

Bitcoin Core Development

At the “Bitcoin Burg Academy” I talked about Bitcoin Core development to an non-technical audience. Often when I talk to non-technical …

OpenSats Work-Log 2

This is a copy of the 2nd work-log I sent to OpenSats for my LTS grant.

Mining Pool Behavior during Forks

I have recently been looking at mining pool behavior during forks. Which block does a pool choose to mine on during a fork? Do they behave rationally …

OpenSats Work-Log 1

This is a copy of the 1st work-log I sent to OpenSats for my LTS grant.

Invalid F2Pool blocks 783426 and 784121 (April 2023)

My notes on the two bad-blk-sigops: too many sigops invalid blocks, 783426 and 784121, mined by F2Pool in April 2023.

Update on LinkingLion: Reduced activity and a statement by LionLink Networks

This is an update on the LinkingLion entity, presumably linking Bitcoin transactions to IP addresses, I published about a year ago. Yesterday, …

Vulnerability Disclosure: Wasting ViaBTC's 60 EH/s hashrate by sending a P2P message

In January, while investigating a misbehaving client on the Bitcoin P2P network, I found a vulnerability in ViaBTC’s, the fourth largest Bitcoin …

ViaBTC's mutated blocks without witness data

I noticed multiple ERROR: AcceptBlock: bad-witness-nonce-size errors in the debug log of my Bitcoin Core node. These indicate that a block my node …

Long-Term-Support Grant from OpenSats for 2024 and 2025

OpenSats supported my work on Bitcoin in 2024 and 2025 with a Long-Term-Support grant.

Spiral Work-Log Q4 2023

This is a copy of the Q4 2023 work-log I sent to Spiral for my grant.

An overview of recent non-standard Bitcoin transactions

This blog post provides an overview of non-standard transactions that mining pools included in the last 117000 Bitcoin blocks.

CPU usage of Bitcoin Core peers

To help improve partition resistance, a medium-term goal is to increase the number block relay connections a Bitcoin Core node has (see #28462). …

Six OFAC-sanctioned transactions missing

My project, miningpool-observer, aims to detect when Bitcoin mining pools are not mining transactions they could have been mining. Over the past few …

FFM BTC Meetup: New features in Bitcoin Core v26.0

The upcoming Bitcoin Core v26.0 release will include new experimental features like AssumeUTXO and P2P transport v2.

Spiral Work-Log Q3 2023

This is a copy of the Q3 2023 work-log I sent to Spiral for my grant.

bitcoin++23 Workshop: Writing a NixOS Module for your_app

Instructions for my Writing a NixOS Module for your_app workshop. Slides can be found here.

Workshop: Writing a NixOS module for YOUR_APP

I held a workshop about “Writing a NixOS module for YOUR_APP”.

Invalid MARAPool block 809478

Notes on the invalid Bitcoin mainnet block at height 809478 mined by experimental, in-house MARAPool mining pool software on September 27, 2023.

Support from MIT DCI for peer-observer

The MIT DCI supported my peer-observer project with six monitoring Bitcoin nodes for 1.5 years.

GitHub Metadata Backup and Mirror

This year, the Bitcoin Core project will have its 13th anniversary being hosted on GitHub. 13 years of issues and pull requests with critical design …

Grant from Human Rights Foundation

The Human Rights Foundation supported my work on Bitcoin with a developer grant.

LinkingLion: An entity linking Bitcoin transactions to IPs?

This post describes and discusses the behavior of an entity I call LinkingLion. The entity opens connections to many Bitcoin nodes using four IP …

Grant from Spiral.xyz for 2023

Spiral.xyz supported my work on Bitcoin for the full year of 2023 with a developer grant.

2022 Review and 2023 Outlook

In this post, I revisit my plans and projects for 2022, and give an outlook for 2023. I plan to continue my current Bitcoin network monitoring efforts …

Inbound Connection Flooder Down (LinkingLion)

Over the past few months, I’ve repeatedly observed very short-lived P2P connections with fake user agents being made to my Bitcoin Core node in …

Are you a real Bitcoiner?

It’s well known that you are only a real Bitcoiner if you are a carnivore, eat red meat at least three times a week but never consume seed oils, …

P2TR spending transactions missing from F2Pool and AntPool blocks (2021)

My miningpool-observer project aims to detect when mining pools don’t mine transactions they could have mined. Right after taproot activation, …

bitcoin++ workshop: Tracing Bitcoin Core v23.0

These are the tasks of my “Tracing Bitcoin Core v23.0” workshop for bitcoin++ 2022. They might not make much sense on their own as …

Workshop: Tracing Bitcoin Core v23.0

I’ve held a workshop showcasing the new tracepoints and tracing functionallity included in Bitcoin Core release v23.0.

0xB10C – Tracepoints and monitoring the Bitcoin network

Jonas, Murch, and I chat about monitoring Bitcoin mining pools and tracing Bitcoin Core.

Monitoring Bitcoin mining pool transaction selection

Can we detect transaction censorship by mining pools on the Bitcoin network?

I spoke at the MIT Bitcoin Expo 2022 about mining pool transaction …

Grant from Bitcoin Suisse (not accepted)

Bitcoin Suisse suprise-announced that they had selected me for a Research Grant.

P2P monitoring

I presented my planned P2P monitoring project to CoreDev attendees.

Grant from Brink for 2022

Brink.dev supported my work on Bitcoin for the full year of 2022 with a developer grant.

Extracting the Private Key from Schnorr Signatures that reuse a Nonce

Elliott (aka @robot__dreams) posted a Bitcoin-flavored cryptography challenge on Twitter. The goal is to extract the private key from two Schnorr …

Bitcoin Core PR Review Club: #20827

I’ve prepared and moderated a Bitcoin Core PR review club meeting on luke-jr’s PR #20827: During IBD, prune as much as possible until we …

Bitcoin Core PR Review Club: #23724

I’ve prepared and moderated a Bitcoin Core PR review club meeting on my PR #23724: add systemtap’s sys/sdt.h as depends for GUIX builds …

Monitoring Taproot Activation

In November 2021, the Taproot soft-fork activated on the Bitcoin network. I streamed my activation monitoring and helped pools not mining P2TR spends …

Updates on USDT in Bitcoin Core

I updated about my recent work on Userspace, Statically Defined Tracing (USDT) support for Bitcoin Core, and showed examples. We discussed where debug …

Update on Reorgs on SigNet

I updated about my recent work on reorgs on SigNet and showed a work-in-progress block tree visualization. Approach and reorg parameters were …

Userspace, Statically Defined Tracing support for Bitcoin Core

This report updates on what 0xB10C, Coinbase Crypto Community Fund grant recipient, has been working on over the first half of his year-long Bitcoin …

Contribution: Bitcoin Core Project

I list my contributions to the Bitcoin Core project and detail their context and background. Of course, not all contributions are worth mentioning …

On anyone-can-spend Pay-to-Taproot outputs before activation

While working on taproot support for transactionfee.info, it became apparent that there already exist a few Pay-to-Taproot (P2TR) outputs on mainnet. …

Summer of Bitcoin 2021

This is a placeholder for the Summer of Bitcoin mentoring I did. I plan to fill this in, once I get the time to do so.

bitcoind-observer

My experimental bitcoind-observer tool is a Bitcoin Core Prometheus metrics exporter utilizing and demonstrating the newly added tracepoints in …

Bitcoin Core PR Review Club: #22006

I’ve prepared and moderated a Bitcoin Core PR review club meeting on my PR #22006 Tracing: first tracepoints and documentation on User-Space, …

Regulatory conform mining on einundzwanzig Podcast (German)

Dennis Reimann and I chat about regulatory conform mining in the context of my miningpool.observer project.

miningpool-observer: Observing Bitcoin Mining Pools

My miningpool-observer project aims to bring transparency to mining pool transaction selection. The tool can detect missing and extra transactions in …

Grant from Coinbase for 2021

Coinbase Giving provided a Bitcoin developer grant my work on Bitcoin in 2021.

Evolution of the signature size in Bitcoin

Digital signatures are an essential building block of the Bitcoin protocol and account for a large part of the data stored on the blockchain. We …

Support from Samourai Wallet for mempool.observer

Samourai Wallet supported my work on mempool.observer with a one-time donation that payed for hosting costs.

Following the Blockchain.com feerate recommendations

Transactions sent with Blockchain.com wallets make up for about a third of all Bitcoin transactions. A methodology to identify these transactions is …

The daily BitMEX broadcast at 13:08 UTC

At around 13:00 UTC every day, BitMEX, a cryptocurrency exchange and derivative trading platform, broadcasts multiple megabytes of large transactions …

The stair-pattern in time-locked Bitcoin transactions

Some of the regularly used Bitcoin wallets, for example, the Bitcoin Core wallet and the Electrum Bitcoin Wallet, set the locktime of newly …

BIP42 on einundzwanzig Podcast (German)

Dennis Reimann and I chat about BIP42. We talk about the background of BIP42, Satoshi’s implementation of the subsidy function, the bug in the …

Interview on einundzwanzig Podcast (German)

Dennis Reimann and I talk about my projects, the Chaincode Labs Residency, and more on the German einundzwanzig Podcast.

transactionfee.info (2020 version)

The website transactionfee.info shows Bitcoin protocol layer statistics. This includes statistics about Bitcoin transactions, their in- and outputs, …

Contribution: Colab version of the Optech Schnorr / Taproot Workshop

Bitcoin Optech created a workshop explaining the Schnorr and Taproot upgrade to engineers. However, users needed to compile a patched version of …

Frequently Asked Questions: Bitcoin Transaction Monitor

The Bitcoin Transaction Monitor provides deeper insights into the usage of the Bitcoin network by showing transactions by time and feerate. This post …

Bitcoin Transaction Monitor

Whenever you, an exchange or somebody else sends a Bitcoin transaction, it gets broadcast to all nodes in the Bitcoin network. Each broadcast …

ShiftCrypto sponsoring mempool.observer

ShiftCrypto sponsored some of my work on mempool.observer.

rawtx library

The rawtx Golang module helps you (and me) to answer questions about raw Bitcoin transactions, their inputs, outputs, and scripts. I use the rawtx …

The Incomplete History of Bitcoin Development

To fully understand the rationale behind the current state of Bitcoin development, knowledge about historical events is essential. This blog post …

Timeline: Historical events in the development of Bitcoin

To fully understand the rationale behind the current state of Bitcoin development, knowledge about historical events is essential. I created an …

A List of Public Bitcoin Feerate Estimation APIs

My search for a list of public Bitcoin feerate estimation APIs ended without any real results. Jameson Lopp has a section on feerate estimators on his …

How Bitcoin Core works: LoadMempool() and DumpMempool()

I’ve talked about the LoadMempool() and DumpMempool() functions of Bitcoin Core at the 2019 Chaincode Labs Summer Residency seminar. These …

BIP-42: A finite monetary supply for Bitcoin

I’ve talked about BIP-42 at the 2019 Chaincode Labs Summer Residency seminar. With BIP-42 a fix for a bug in the block subsidy calculation of …

BIP-125: Opt-in Full Replace-by-Fee Signaling

I’ve presented about BIP-125 Replace-by-Fee at the 2019 Chaincode Labs Summer Residency seminar. This talk was about the motivation, the …

Building mempool.observer - mempool stats and visualizations

I’ve presented my mempool.observer project at the 93rd NYC BitDevs Socratic Seminar. This included past challenges, current todo’s and …

mempool.observer (2019 version)

The mempool.observer website displays visualizations about my Bitcoin mempool. For example, a visualization of my current mempool and the historical …

mempool-dat

A Golang package that can deserialize Bitcoin Core’s mempool.dat files. This is a toy project. I developed this to learn more about Golang and …

c-lightning plugin: csvexportpays

A toy plugin for c-lightning to export all payments made with a c-lightning node to a .csv file. I build this a few days after Blockstream released …

Support from Bitrefill for transactionfee.info

Bitrefill supported my work on transactionfee.info (now mainnet.observer).

lnplays.com

Konstantin Nick (@sputn1ck) and I build lnplays.com for the Lighting Hackday in June 2018. You could play Pokémon via the Lightning Network build. …

Plotting the Bitcoin Feerate Distribution

How did the median Bitcoin feerate evolve from 2013 to 2015? When were the feerate spikes in 2017? Visualizing the Bitcoin feerate distribution per …

transactionfee.info (2018 version)

We build transactionfee.info in 2018 to raise awareness about the inefficient use of block space by exchanges, services, and wallets. The project is a …

The 300 MB default maxmempool Problem

Unconfirmed transactions are quite a hassle for bitcoin users. I recently came across an interesting problem which is not the usual “my …

mempool.observer (2017 version)

The mempool.observer website displays statistics about my Bitcoin mempool. This covers the 2017 version which I iterated on in 2019.