Skip to content

Instantly share code, notes, and snippets.

Avatar

chris-belcher

View GitHub Profile
@chris-belcher
chris-belcher / sorted-merkle-tree-issue693.md
Last active Nov 19, 2022
Sorted merkle tree as solution to issue #693
View sorted-merkle-tree-issue693.md

The Problem

JoinMarket has a problem where it assumes different nicknames have different bitcoin wallets. This can be exploited by people running multiple yield generator bots from the same wallet, so they get a higher rate of profit at the expense of de-legitimizing the system for privacy.

Crypto primitive 1: Merkle Tree

A merkle tree is a way of producing a commitment to a set, which can later can prove that elements are contained within the set using only O(logN) data, and only revealing one other element in the set.

For example here is a merkle tree commiting to a set of numbers {6, 3, 9, 0, 8, 4, 7, 2}

@chris-belcher
chris-belcher / work-diary.md
Last active Nov 17, 2022
Chris Belcher work diary
View work-diary.md
@chris-belcher
chris-belcher / coinswap-design.md
Last active Sep 10, 2022
Design for a CoinSwap Implementation for Massively Improving Bitcoin Privacy and Fungibility
View coinswap-design.md

Design for a CoinSwap Implementation for Massively Improving Bitcoin Privacy and Fungibility

25/5/2020

Abstract

Imagine a future where a user Alice has bitcoins and wants to send them with maximal privacy, so she creates a special kind of transaction. For anyone looking at the blockchain her transaction appears completely normal with her coins seemingly going from address A to address B. But in reality her coins end up in address Z which is entirely unconnected to either A or B.

Now imagine another user, Carol, who isn't too bothered by privacy and sends her bitcoin using a regular wallet which exists today. But because Carol's transaction looks exactly the same as Alice's, anybody analyzing the blockchain must now deal with the possibility that Carol's transaction actually sent her coins to a totally unconnected address. So Carol's privacy is improved even though she didn't change her behaviour, and perhaps had never even heard of this software.

@chris-belcher
chris-belcher / pro-decentralization-link-list.md
Last active Jun 11, 2022
pro-decentralization-link-list
View pro-decentralization-link-list.md
@chris-belcher
chris-belcher / financial-mathematics-of-joinmarket-fidelity-bonds.md
Last active Jun 2, 2022
Financial mathematics of joinmarket fidelity bonds
View financial-mathematics-of-joinmarket-fidelity-bonds.md
@chris-belcher
chris-belcher / JMalert.md
Last active May 15, 2022
JoinMarket release 0.2.0 ameliorates this snooping attack.
View JMalert.md
@chris-belcher
chris-belcher / design-for-improving-joinmarkets-resistance-to-sybil-attacks-using-fidelity-bonds.md
Last active Dec 4, 2021
Design for improving JoinMarket's resistance to sybil attacks using fidelity bonds
View design-for-improving-joinmarkets-resistance-to-sybil-attacks-using-fidelity-bonds.md

Design for improving JoinMarket's resistance to sybil attacks using fidelity bonds

13/7/2019

tl;dr

JoinMarket can be sybil attacked today at relatively low cost which can destroy its privacy. Bitcoins can be sacrificed with burner outputs and time-locked addresses (also called fidelity bonds), and this can be used to greatly improve JoinMarket's resistance to sybil attacks.

With real-world data and realistic assumptions we calculate that under such a fidelity bond system an adversary would need to lock up 30,000-80,000 bitcoins for months, or send 45-120 bitcoins to burner addresses to have a good chance of sybil attacking the system if it were added to JoinMarket.

@chris-belcher
chris-belcher / alectryon.py
Last active Nov 7, 2021
bitcoin-blockchain-feed-bot
View alectryon.py
#jsonrpc.py from https://github.com/JoinMarket-Org/joinmarket/blob/master/joinmarket/jsonrpc.py
#copyright # Copyright (C) 2013,2015 by Daniel Kraft <d@domob.eu> and phelix / blockchained.com
import base64
import httplib
import json
class JsonRpcError(Exception):
def __init__(self, obj):
self.message = obj
@chris-belcher
chris-belcher / privacy-liquidity-divisibility.md
Last active Jun 3, 2021
How Wasabi Wallet and Samourai Wallet slightly degrade the divisibility of bitcoin
View privacy-liquidity-divisibility.md

How Wasabi Wallet and Samourai-Wallet-Whirlpool slightly degrade the divisibility of bitcoin

December 2018

I made this claim on twitter recently and many people wanted me to go into more detail.

Lots of privacy tech in bitcoin like coinjoin, coinswap, tumblebit and Lightning Network require many entities to come together to agree to make certain kinds of transactions. This creates a requirement that the right resources (coins) have to be in the right place,