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Last active February 27, 2021 21:35 — forked from chris-belcher/coinswap-design.md
Design for a CoinSwap Implementation for Massively Improving Bitcoin Privacy and Fungibility

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.

{
"nonce": "0x0000000000000042",
"difficulty": "0x40000",
"alloc": {
"bbbbbaaaaa82db86a35502193b4c6ee9a76ebe8f": {
"balance": "10015200000000000000000"
},
},
"mixhash": "0x0000000000000000000000000000000000000000000000000000000000000000",
"coinbase": "0x0000000000000000000000000000000000000000",
#!/usr/bin/env python
import hmac
import hashlib
from sys import argv, exit, stderr
def hmac_sha512(key, message):
return hmac.new(key, message, hashlib.sha512).hexdigest()
def roll(server_seed, client_seed, nonce):
# Generate key and message strings.