AdamISZ

Described here is a variant of what has previously been published under the name "P2EP" or Pay-to-endpoint, in which A pays B but B contributes utxos, i.e. it's a coinjoin-payment.

I'm using the term "payjoin" here to refer to using that idea, but not including a URI/endpoint specific to B, and not allowing (as a merchant would) arbitrary payments, which opens up certain problems around snooping attackers (more on this below). So payjoin just means "A pays B but B actively participates and passes across utxos as extra inputs".

I'll defer a more features-focused and non-tech friendly description of what this means to a later blogpost.

AdamISZ

Looking for optimally minimal data transfer to send a transaction.

Just throwing this out there; I'm sure we can do better.

Some stuff should be pre-agreed by anyone following this protocol. For example:

• Preagreed: script type (say legacy P2PKH)
• Preagreed: version 1, locktime 0, sequence maxint-1, fee 10K sats (tweak this later)

Receiver has address AR, requests X sats.

AdamISZ

from __future__ import (absolute_import, division,
                        print_function, unicode_literals)
from builtins import * # noqa: F401
import os
from optparse import OptionParser
from jmbase import jmprint
from jmclient import load_program_config, open_test_wallet_maybe

def get_wallet_path(file_name, wallet_dir):
    # TODO: move default wallet path to ~/.joinmarket

AdamISZ

General idea; generalise the Schnorr scriptless script atomic swap of A Poelstra to multiple parties.

We consider 3-party case with trivial generalisation. Parties are Alice, Bob, Charlie, A, B, C. Payment destinations are D_x. Transactions are TX_x. Adaptor signature secrets are t_x (scalar), T_x (point). Signatures are "sigma", adaptor signatures will be marked with '.

(

AdamISZ

#!/usr/bin/env python
from __future__ import print_function
"""
Find/count JM transactions in blocks.
Ensure your joinmarket-clientserver virtualenv (jmvenv) is activated,
make sure your Bitcoin Core node is available and joinmarket.cfg is appropriately set.

Pass start and end block number:
`python jmtxfinder.py 400000 400200`.

AdamISZ

  BIP: ??
  Layer: Applications
  Title: SNICKER - Simple Non-Interactive Coinjoin with Keys for Encryption Reused
  Author&#58; Adam Gibson <AdamISZ@protonmail.com>
  Comments&#45;Summary&#58; No comments yet.
  Comments&#45;URI&#58; &#45;
  Status&#58; Proposed
  Type&#58; Informational
  Created&#58; &#45;

AdamISZ

Fidelity Bonds in an Anonymity set

If timelocked outputs are used as fidelity bonds, there is some inevitable degradation in the anonymity of users of a system that requires such bonds. Part of this would be entirely unavoidable - in that when the utxo is spent, the CLTV nature of the scriptPubKey must be revealed, and in most scenarios this would probably watermark that the utxo was being used for a fidelity bond purpose. But what might be avoided is the tracing, or linking, of a particular utxo used repeatedly for the same purpose.

Concrete case: Joinmarket maker

To make the issue clearer, consider the specific case of Joinmarket, and the recent proposal on fidelity bonds by Chris Belcher [1]. Here, the fidelity bond would be used to sign an ephemeral identity used on a message channel. The user, having committed funds to the bond, would perforce re-use that same bond every time he reconnects to the trading pit and so what is currently a completely ephemeral identity (it can be changed as often as

AdamISZ

#!/usr/bin/env python3

""" This represents a brief check of mainnet transaction:
ba29e5c66bc0ce15a0228d47514f1de2a5737f2eb185c30589bfd4a735d78c1f

in particular, assuming the four inputs identified below as "known_ins",
i.e. there is an assumption they are co-owned by one entity, this identifies
possible combinations of the other inputs, with this set of inputs,
that matches the change output according to taker/maker role, applying a sudoku.

AdamISZ

Some blue sky thinking about Joinmarket architecture (this is about the "client" side of "client-server" in the sense used in the name of the repo; there, the "server" is the communications daemon which can run somewhere else, and I'm not suggesting changing that).

Though the idea has cropped up several times (because it is a very natural concept in software engineering, and is widely used), I started today thinking again about having something like an RPC API for a Joinmarket long-running daemon (this would be *another* daemon to the one mentioned above). Let's call it jmwalletd to distinguish from existing joinmarketd (badly named in retrospect), and called that because as you see below the idea is to bundle the services around the wallet.

The reason I started thinking about it today again, was because of SNICKER; and I'll use that as an example of how this might create benefits (along with some benefits that would exist without new functionality).

Imagine then that jmwalletd.py runs as a service or simi

AdamISZ

Setup paying hot wallet btcpayserver to joinmarket all on one machine, on regtest:

1. Follow installation instructions from scratch as per: https://docs.btcpayserver.org/LocalDevelopment/ (note, there is another setup description, but it is specifically for coding and debugging, using visual studio, here: https://docs.btcpayserver.org/Contribute/ContributeDev/ContributeDevCode/#visual-studio-setup)

2. after the docker-compose up dev command specified there, run dotnet run --launch-profile Bitcoin from BTCPayServer directory (should not need to change any config)

3. Load http://127.0.0.1:14142 to get the BTCPayServer UI

4. Create an Admin account (check the option) with a random email and password. New screen should show 'Regtest' and 'Server Settings'.