PSBT Faker

A simple program to create test PSBT files, that are plausible and self-consistent so that PSBT-signing tools will actually sign them. Does not involve any blockchains... completely made up inputs and output addresses are chosen at random.

You should use the XPUB of the Coldcard you want experiment against. This can be retrieved using ckcc xpub with the ckcc-protocol CLI tool, or by exporting the wallet (see Advanced > MicroSD > Export Wallet menu).

For the Coldcard Simulator, you could use tpubD6NzVbkrYhZ4XzL5Dhayo67Gorv1YMS7j8pRUvVMd5odC2LBPLAygka9p7748JtSq82FNGPppFEz5xxZUdasBRCqJqXvUHq6xpnsMcYJzeh

Installation

git clone https://github.com/Coldcard/psbt_faker.git
cd psbt_faker
python3 -m pip install -U pip setuptools
python3 -m pip install --editable .
rehash

Usage

$ psbt_faker --help

Usage: psbt_faker [OPTIONS] OUTPUT.PSBT [XPUB]

  Construct a valid PSBT which spends non-existant BTC to random addresses!

Options:
  -n, --num-outs INTEGER          Number of outputs (default 1)
  -c, --num-change INTEGER        Number of change outputs (default 1)
  -v, --value INTEGER             Total BTC value of inputs (integer, default
                                  3)
  -f, --fee INTEGER               Miner's fee in Satoshis
  -s, --segwit                    Make ins/outs be segwit style
  -a, --styles [p2wpkh|p2wsh|p2sh|p2pkh|p2wsh-p2sh|p2wpkh-p2sh|p2tr]
                                  Output address style (multiple ok)
  -6, --base64                    Output base64 (default binary)
  -t, --testnet                   Assume testnet3 addresses (default mainnet)
  -p, --partial                   Change first input so its different XPUB and
                                  result cannot be finalized
  -z, --zero-xfp                  Provide zero XFP and junk XPUB (cannot be
                                  signed, but should be decodable)
  --help                          Show this message and exit.

Examples

$ export XPUB=tpubD6NzVbkrYhZ4Xp6tGusznF6KMdYHy1JSCdDk3XVLDuAA7EgJKghA5J1FP4pDXb4sCypJjAYPB4uTTXkVo2iWzK8BsMaccXTNyShDx3gxagi

$ psbt_faker foo.psbt $XPUB -s -a p2wsh --fee 15000000 -c 0

Fake PSBT would send 3 BTC to: 
 2.85000000 => bc1qqalzjffzy9nwcd35t0phdyugdmmqpskldgcw3xd40qxh32z908msf5alem 
 0.15000000 => miners fee

$ psbt_faker foo.psbt $XPUB -n 10

Fake PSBT would send 3 BTC to: 
 0.27272636 => 17VardgvHiYjDEtpBRWpqQLgrvKDUiGGaW 
 0.27272636 => 1A1FDLRD1caNjbwpr4odqpcB2sGgZSgGqZ 
 0.27272636 => 1P3Zr4zQko2CDbDDiqrkMduSppNB3Pb1Aq 
 0.27272636 => 1LcDusCVB6KjjAcrk5NvscV4AQ3cRJTR8j 
 0.27272636 => 15oy1fAxnbYr6Vgz7eNwjBQfujdvssdRaG 
 0.27272636 => 1EkYuiLo9Tt3cYCJwMfDvX38MddTBMqPc1 
 0.27272636 => 185VxgHqCEYudH6XXwdDiQtqfEUXGMxSXJ 
 0.27272636 => 19dR12aRSj8nyUaJLM11ruExa7N6jdAmUJ 
 0.27272636 => 1Ppj73d7z6cQvKhzezmaBywbJRSUnrymPE 
 0.27272636 => 1CPCdAWTrVqgS8cHVTbDQwkCvASjTfcaTe 
 0.27272636 => 1F2WTuA3BRpYmM82gsLuAdyAiLPYoUYijP  (change back)
 0.00001000 => miners fee


$ psbt_faker foo.psbt $XPUB -n 3 -v 100 -c 10

Fake PSBT would send 100 BTC to: 
 7.69230692 => 13mRoGiQHzmPhaCgQZbjw42njWhV3ymqDw 
 7.69230692 => 1MMbuGuuaJ9GnRXh4ixa6xiKER3xzg52TJ 
 7.69230692 => 1NjnUBrWSSx8iK5TC3XJXqQ7grC23kpZX2 
 7.69230692 => 1Aq96VVsd2nocTqAYQ4PnD6XhotKqmrBNn  (change back)
 7.69230692 => 1Bj7KprFDJ1d1F1se3DKedASFYvjWNaZMT  (change back)
 7.69230692 => 1HVTgLgZF95tF4B1CJk4BEvkLmT3hYDrmA  (change back)
 7.69230692 => 17Uz3tHeG1Zf8W4hmst2kQtbH17tHe3UTN  (change back)
 7.69230692 => 1LyLjaPcXbo5TxJYMYyUT9HzCgkJnKef1j  (change back)
 7.69230692 => 19DasuH8grQGc4MrPPR5abYUZAKF9UbbwZ  (change back)
 7.69230692 => 1JpymwTGWfXpcurLnsFbLcPRnkkzvRiKsy  (change back)
 7.69230692 => 1PoFUSStjmogrv2eEtRjbpz8N5reETVVZn  (change back)
 7.69230692 => 1Q8yrQsHotMNkrsAyEynDAuqC8rDs7nG41  (change back)
 7.69230692 => 1AbiaE64hjUygVoqkedaLvneHht8bbvPgo  (change back)
 0.00001000 => miners fee

psbt_faker foo.psbt $XPUB -n 10 -a p2wpkh -a p2wsh -a p2sh -a p2pkh -a p2wsh-p2sh -a p2wpkh-p2sh

Fake PSBT would send 3 BTC to: 
 0.27272636 => bc1q2l0zgfksxacs8hdxwmq56ftpzagcyvq8z237qf 
 0.27272636 => bc1q4ru6vpngexl348we0fkydheat3azcvr96uc975tmvcy0z8kjaz6qz30498 
 0.27272636 => 37Axq8rmQGjEHVoCb877RiNfWnnMtFCZ6H 
 0.27272636 => 16JDSqRVvYdWV4KntQ5wjUK5es6CaiTyBc 
 0.27272636 => 3HXq92K1xvx6QMNmQTHPWPLNiEReez595d 
 0.27272636 => 3LyBpZ2aaTs1Qj1NFmGGttL8PyhEzB9iDW 
 0.27272636 => bc1qsplnzq8n500q4zg6a8m2nj4c8ygvlp8p8zuppc 
 0.27272636 => bc1qw9hery5rjcujuf3f09djlxepepx6luen7jq9t0hfsu44dv3t6x3s4k4aw5 
 0.27272636 => 3Ld1TUaWQouRRGGAc8PSzvqtgjfyxdM3Vr 
 0.27272636 => 1ABmPHMdqK4MqF9BkACv8PHHYL7McmbYAq 
 0.27272636 => 15mkVohf2A1g9nVo9tn2KtN2f4eBHQCche  (change back)
 0.00001000 => miners fee