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View GitHub Profile
View rbtc-censorship.md

r/btc markets itself as a "censorship-free" sub. In reality it attempts to silence the voices of people it disagrees with.

A few screenshot examples of censorship https://imgur.com/a/rHrtC

this article was deleted when posted, which describes how the mods of r/btc are roger ver's employees at bitcoin.com https://medium.com/@WhalePanda/the-curious-relation-between-bitcoin-com-anti-segwit-propaganda-26c877249976#.4mfo9qn3e

"Exploit code for the recent BTU attack - apparently this was posted to /r/btc, and of course, got censored. :)"

@chris-belcher
chris-belcher / sorted-merkle-tree-issue693.md
Last active Nov 20, 2019
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 / improvement-plan-for-joinmarket-tumbler.md
Last active Nov 3, 2019
Plan to improve the privacy of JoinMarket's tumbler script
View improvement-plan-for-joinmarket-tumbler.md

Plan to improve the privacy of JoinMarket's tumbler script

24/02/2019

JoinMarket has a tumbler application which aims to send bitcoins in a way that delinks the origin and destination.

I have some thoughts on how and why to improve the tumbler algorithm.

Feel free to bikeshed some of these parameters (averages, counts, etc), as my important points are about other stuff.

@chris-belcher
chris-belcher / design-for-improving-joinmarkets-resistance-to-sybil-attacks-using-fidelity-bonds.md
Last active Oct 7, 2019
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 / financial-mathematics-of-joinmarket-fidelity-bonds.md
Last active Aug 23, 2019
Financial mathematics of joinmarket fidelity bonds
View financial-mathematics-of-joinmarket-fidelity-bonds.md

Financial mathematics of JoinMarket fidelity bonds

13/7/2019

To read the context see the main document Design for improving joinmarket's resistance to sybil attacks using fidelity bonds.

Valuing fidelity bonds

We want to come up with a mathematical formula which gives the value of a fidelity bond. We want this function to be in the best interests of takers who use it. We aim for them to get the best possible sybil resistance.

View pro-decentralization-link-list.md
@chris-belcher
chris-belcher / sybil-attack-success-prob.py
Created Jul 13, 2019
Sybil attack success probability
View sybil-attack-success-prob.py
#! /usr/bin/python3
##this file calculates the success probability of a sybil attack on the
# orderbook with fidelity bonds used in joinmarket
# see https://gist.github.com/chris-belcher/87ebbcbb639686057a389acb9ab3e25b
from scipy.optimize import brentq
from time import time
from datetime import timedelta
@chris-belcher
chris-belcher / privacy-liquidity-tech.md
Last active Jul 9, 2019
Notes on paying for liquidity for privacy tech: regarding JoinMarket and Wasabi Wallet
View privacy-liquidity-tech.md

Notes on paying for liquidity for privacy tech: regarding JoinMarket, Wasabi Wallet and P2EP

December 2018

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, at the right time, in the right quantity. This isn't a software or tech problem, its an economic problem of liquidity.

View block-probability.py
import matplotlib
import numpy.random
import matplotlib.pyplot as plt
from matplotlib.ticker import FuncFormatter
#https://www.reddit.com/r/Bitcoin/comments/4gp28d/how_to_avoid_getting_ripped_off_in_large_btc/
#https://en.bitcoin.it/wiki/Confirmation
cumulative = True
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