Code used to create transaction 749fdc72f1c99398899425253875deb1d7e5e040db14014ea57db71c610dad26 - #FreeSamourai

tx-ascii-art.js

#! /usr/bin/env node

const fs = require("fs");
const bitcoin = require("bitcoinjs-lib");
const ecc = require("tiny-secp256k1");
const { ECPairFactory } = require("ecpair");
const ECPair = ECPairFactory(ecc);
bitcoin.initEccLib(ecc);

const network = bitcoin.networks.bitcoin;
const wif = "<to_be_filled>";

const keyPair = ECPair.fromWIF(wif, network);
const internalPubkey = keyPair.publicKey.subarray(1);
const { output } = bitcoin.payments.p2tr({ internalPubkey, network });

const tweakedKeyPair = keyPair.tweak(
    bitcoin.crypto.taggedHash("TapTweak", internalPubkey),
);

const inputValue = 3501;
const burnValue = 1;

const psbt = new bitcoin.Psbt({ network });
psbt.addInput({
    hash: "<to_be_filled>",
    index: 1,
    witnessUtxo: {
        script: output,
        value: inputValue
    },
    tapInternalKey: internalPubkey
});

const outputs = asciiFileToOutputs("art.txt");
psbt.addOutputs(outputs);

psbt.signAllInputs(tweakedKeyPair);
psbt.finalizeAllInputs();

const fee = inputValue - burnValue * outputs.length;
const tx = psbt.extractTransaction();
const size = tx.virtualSize();
const feeRate = (fee / size).toFixed(2);

console.log(`Size: ${size} vb`);
console.log(`Fee: ${fee} sats`);
console.log(`Fee: ${feeRate} sat/vb`);

console.log();
console.log("\nTransaction hex:")
console.log(tx.toHex());

function asciiFileToOutputs(filename) {
    const content = fs.readFileSync(filename).toString().trim().split("\n");
    const outputs = [];

    for (const line of content) {
        const data = Buffer.from(line, "utf8");
        const embed = bitcoin.payments.embed({ data: [data] });
        outputs.push({
            script: embed.output,
            value: burnValue,
        });
    }

    return outputs;
}