Trent Brooks trentbrooks

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.

Firebase Topic Counter

This little script will output the amount of tokens subscribed to a topic.
You will need to replace the variables with your personal ones in order for it to work.

We used this function in a Lambda which sends the results to a monitoring dashboard.

How to get the variables

Screenshots in the comments.

Go to the Firebase Console.

S3 Static Sites

⚠ This post is fairly old. I don't keep it up to date. Be sure to see comments where some people have posted updates

What this will cover

Host a static website at S3
Redirect www.website.com to website.com
Website can be an SPA (requiring all requests to return index.html)
Free AWS SSL certs
Deployment with CDN invalidation

Installing Python 3.6 on Raspbian

As of January 2018, Raspbian does not yet include the latest Python release, Python 3.6. This means we will have to build it ourselves, and here is how to do it. There is also an ansible role attached that automates it all for you.

Install the required build-tools (some might already be installed on your system).

#!/usr/bin/env bash

# Assuming OS X Yosemite 10.10.4

# Install XCode and command line tools
# See https://itunes.apple.com/us/app/xcode/id497799835?mt=12#
# See https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/xcode-select.1.html
xcode-select --install

	import argparse
	import requests

	def get_allocation(address, blockchain):
	id = {
	"sol": 1,
	"eth": 2,
	"sui": 21,
	"aptos": 22,
	"inj": 19,

	"""
	Python code for fractional differencing of pandas time series
	illustrating the concepts of the article "Preserving Memory in Stationary Time Series"
	by Simon Kuttruf

	While this code is dedicated to the public domain for use without permission, the author disclaims any liability in connection with the use of this code.
	"""

	import numpy as np
	import pandas as pd

	contract random {
	/* Generates a random number from 0 to 100 based on the last block hash */
	function randomGen(uint seed) constant returns (uint randomNumber) {
	return(uint(sha3(block.blockhash(block.number-1), seed ))%100);
	}

	/* generates a number from 0 to 2^n based on the last n blocks */
	function multiBlockRandomGen(uint seed, uint size) constant returns (uint randomNumber) {
	uint n = 0;
	for (uint i = 0; i < size; i++){

	import Foundation
	import CryptoSwift

	extension String {

	func aesEncrypt(key: String, iv: String) throws -> String{
	let data = self.dataUsingEncoding(NSUTF8StringEncoding)
	let enc = try AES(key: key, iv: iv, blockMode:.CBC).encrypt(data!.arrayOfBytes(), padding: PKCS7())
	let encData = NSData(bytes: enc, length: Int(enc.count))
	let base64String: String = encData.base64EncodedStringWithOptions(NSDataBase64EncodingOptions(rawValue: 0));

	extension Array {

	func first() -> Element? {
	if isEmpty {
	return nil
	}
	return self[0]
	}

	func last() -> Element? {