AdamISZ

We are working in pairs. One person is HOLDER. One person is RECEIVER.

Instructions for RECEIVER

As receiver, you don't know much about Bitcoin!! So:

1. Download a wallet on your phone. There are many apps, but we need to use signet. Please download Padawan wallet on Android or iPhone , which is signet by default and is very simple. If that fails, use the Electrum wallet on your computer, as instructed to the HOLDER.
2. Create a new wallet, write down the seedphrase on paper, (go to Settings->Recovery Phrase), and create a receiving address. Give the receiving address to your HOLDER.

AdamISZ

We are working in pairs. One person is HOLDER. One person is RECEIVER.

Instructions for HOLDER

You are going to die soon!! Hurry!

1. Download Electrum from https://electrum.org .
2. Run Electrum using ./electrum-4.5.8-x86_64.AppImage --signet on Linux or /Applications/Electrum.app/Contents/MacOS/run_electrum --signet on Mac. On Windows do the same; run the executable FROM THE COMMAND LINE: C:\Program Files (x86)\Electrum> electrum-4.5.8.exe --signet.
3. Go to File-> New/Restore, leave default (standard) wallet and enter a file name. Enter the 12 word seed phrase ("I already have a seed"), choose BIP39 in Options, and recover the wallet. It should contain a bit less than 10M sats.

AdamISZ

#!/usr/bin/env python3

""" Tool to take sets of Joinmarket coinjoin transactions,
    and do subset sum iteration to find possible sets of taker
    inputs, based on an assumed max possible value of maker fees
    (see tolerance).
"""

from itertools import combinations, chain, product
from jmbitcoin import CTransaction, is_jm_tx

AdamISZ

# A reminder of how to "prove" you're Satoshi.

# ("reminder" - this was done (with tongue in cheek, presumably)
# by someone on Twitter a few years ago).

# 1. We need the public key of the receiving address of (e.g.) block 1.

# it is on the blockchain in uncompressed form (P2PK):

block1_uncompressed_output_key_hex = "0496b538e853519c726a2c91e61ec11600ae1390813a627c66fb8be7947be63c52da7589379515d4e0a604f8141781e62294721166bf621e73a82cbf2342c858ee"

AdamISZ

# Replaced with this: https://github.com/AdamISZ/3roundmusig4fun

AdamISZ

Chaumian cash in a Bitcoin world - cashu, Fedimint

What's this for?

• More scalable/faster than a blockchain (not enough utxos)
• Much better privacy security model than a blockchain
• Same or better theft security model than TTP but much worse than a blockchain

If it's so great, why hasn't it been done yet?

AdamISZ

#!/usr/bin/env python
help = """
A demonstration of the algorithm of
the linkable ring signature algorithm in Goodall and Noether's
Triptych:
https://eprint.iacr.org/2020/018

To use, specify two arguments: n (integer) and m (integer), such
that N (size of ring) = n^m.

AdamISZ

#!/usr/bin/env python
help = """
A demonstration of the algorithm of:
Groth and Kohlweiss 2014 "How to leak a secret and spend a coin."
https://eprint.iacr.org/2014/764.pdf

This uses the Joinmarket bitcoin backend, mostly just for its encapsulation
of the package python-bitcointx (`pip install bitcointx` or github:
https://github.com/Simplexum/python-bitcointx).

AdamISZ

RIDDLE

Due to unexpected failures of github's LaTeX parsing (which were not evident until I published this, but have persisted afterwards), and since the mathematical parts are important in this, I have migrated this proposal to a blog post with identical content, but correctly formatted equations.

Please continue to put any comments here.

AdamISZ

As per footnote 2 in the draft BIP here, it is possible in MuSig2 to create a partial signature which verifies correctly to the other participants, even though the adversary does not know the secret key corresponding to the given public key, but only by the adversary taking the role of at least one other participant, and in that case it is not possible to create a partial signature for that other public key, even if the corresponding private key is known.

The purpose of this gist is to work through the mathematical details of the above statement, as it isn't, probably, obvious to most readers (although it may be at least somewhat intuitive - think about 'free variables').

Setup: keyset $L = X_1 , X_2 , X_3 , X_4 , X_5$. The adversary will take the roles of indices 4 and 5, and will forge a partial signature on key $X_4$, not knowing the corresponding secret $x_4$, on a given message $m$. Assume the adversary does kn