@scure/btc-signer
Advanced tools
Audited & minimal library for Bitcoin. Handle transactions, Schnorr, Taproot, UTXO & PSBT
Audited & minimal library for creating, signing & decoding Bitcoin transactions.
Initial development has been funded by Ryan Shea.
For discussions, questions and support, visit GitHub Discussions section of the repository.
Check out all web3 utility libraries: ETH, BTC, SOL, ordinals
scure — audited micro-libraries.
npm install @scure/btc-signer
We support all major platforms and runtimes. For Deno, ensure to use npm specifier. For React Native, you may need a polyfill for crypto.getRandomValues.
import * as btc from '@scure/btc-signer';
// import * as btc from "npm:@scure/btc-signer@1.0.0"; // Deno
BTC has several UTXO types:
For test examples, the usage is as following:
npm install @scure/btc-signer @scure/base assert
import * as btc from '@scure/btc-signer';
import { hex } from '@scure/base';
import { deepStrictEqual, throws } from 'assert';
Legacy script, doesn't have an address. Must be wrapped in P2SH / P2WSH / P2SH-P2WSH. Not recommended.
const uncompressed = hex.decode(
'04ad90e5b6bc86b3ec7fac2c5fbda7423fc8ef0d58df594c773fa05e2c281b2bfe877677c668bd13603944e34f4818ee03cadd81a88542b8b4d5431264180e2c28'
);
deepStrictEqual(btc.p2pk(uncompressed), {
type: 'pk',
script: hex.decode(
'4104ad90e5b6bc86b3ec7fac2c5fbda7423fc8ef0d58df594c773fa05e2c281b2bfe877677c668bd13603944e34f4818ee03cadd81a88542b8b4d5431264180e2c28ac'
),
});
Classic (pre-SegWit) address.
const PubKey = hex.decode('030000000000000000000000000000000000000000000000000000000000000001');
deepStrictEqual(btc.p2pkh(PubKey), {
type: 'pkh',
address: '134D6gYy8DsR5m4416BnmgASuMBqKvogQh',
script: hex.decode('76a914168b992bcfc44050310b3a94bd0771136d0b28d188ac'),
});
// P2SH-P2PKH
deepStrictEqual(btc.p2sh(btc.p2pkh(PubKey)), {
type: 'sh',
address: '3EPhLJ1FuR2noj6qrTs4YvepCvB6sbShoV',
script: hex.decode('a9148b530b962725af3bb7c818f197c619db3f71495087'),
redeemScript: hex.decode('76a914168b992bcfc44050310b3a94bd0771136d0b28d188ac'),
});
// P2WSH-P2PKH
deepStrictEqual(btc.p2wsh(btc.p2pkh(PubKey)), {
type: 'wsh',
address: 'bc1qhxtthndg70cthfasy8y4qlk9h7r3006azn9md0fad5dg9hh76nkqaufnuz',
script: hex.decode('0020b996bbcda8f3f0bba7b021c9507ec5bf8717bf5d14cbb6bd3d6d1a82defed4ec'),
witnessScript: hex.decode('76a914168b992bcfc44050310b3a94bd0771136d0b28d188ac'),
});
// P2SH-P2WSH-P2PKH
deepStrictEqual(btc.p2sh(btc.p2wsh(btc.p2pkh(PubKey))), {
type: 'sh',
address: '3EHxWHyLv5Seu5Cd6D1cH56jLKxSi3ps8C',
script: hex.decode('a9148a3d36fb710a9c7cae06cfcdf39792ff5773e8f187'),
redeemScript: hex.decode('0020b996bbcda8f3f0bba7b021c9507ec5bf8717bf5d14cbb6bd3d6d1a82defed4ec'),
witnessScript: hex.decode('76a914168b992bcfc44050310b3a94bd0771136d0b28d188ac'),
});
SegWit V0 version of P2PKH. Basic bech32 address. Can't be wrapped in P2WSH.
const PubKey = hex.decode('030000000000000000000000000000000000000000000000000000000000000001');
deepStrictEqual(btc.p2wpkh(PubKey), {
type: 'wpkh',
address: 'bc1qz69ej270c3q9qvgt822t6pm3zdksk2x35j2jlm',
script: hex.decode('0014168b992bcfc44050310b3a94bd0771136d0b28d1'),
});
// P2SH-P2WPKH
deepStrictEqual(btc.p2sh(btc.p2wpkh(PubKey)), {
type: 'sh',
address: '3BCuRViGCTXmQjyJ9zjeRUYrdZTUa38zjC',
script: hex.decode('a91468602f2db7b7d7cdcd2639ab6bf7f5bfe828e53f87'),
redeemScript: hex.decode('0014168b992bcfc44050310b3a94bd0771136d0b28d1'),
});
Classic (pre-SegWit) script address. Useful for multisig and other advanced use-cases. Consumes full output of other payments — NOT only script.
Required tx input fields to make it spendable: redeemScript
const PubKey = hex.decode('030000000000000000000000000000000000000000000000000000000000000001');
// Wrap P2PKH in P2SH
deepStrictEqual(btc.p2sh(btc.p2pkh(PubKey)), {
type: 'sh',
address: '3EPhLJ1FuR2noj6qrTs4YvepCvB6sbShoV',
script: hex.decode('a9148b530b962725af3bb7c818f197c619db3f71495087'),
redeemScript: hex.decode('76a914168b992bcfc44050310b3a94bd0771136d0b28d188ac'),
});
SegWit V0 version of P2SH.
Required tx input fields to make it spendable: witnessScript
const PubKey = hex.decode('030000000000000000000000000000000000000000000000000000000000000001');
deepStrictEqual(btc.p2wsh(btc.p2pkh(PubKey)), {
type: 'wsh',
address: 'bc1qhxtthndg70cthfasy8y4qlk9h7r3006azn9md0fad5dg9hh76nkqaufnuz',
script: hex.decode('0020b996bbcda8f3f0bba7b021c9507ec5bf8717bf5d14cbb6bd3d6d1a82defed4ec'),
witnessScript: hex.decode('76a914168b992bcfc44050310b3a94bd0771136d0b28d188ac'),
});
Not really script type, but construction of P2WSH inside P2SH.
Required tx input fields to make it spendable: redeemScript, witnessScript
const PubKey = hex.decode('030000000000000000000000000000000000000000000000000000000000000001');
deepStrictEqual(btc.p2sh(btc.p2wsh(btc.p2pkh(PubKey))), {
type: 'sh',
address: '3EHxWHyLv5Seu5Cd6D1cH56jLKxSi3ps8C',
script: hex.decode('a9148a3d36fb710a9c7cae06cfcdf39792ff5773e8f187'),
redeemScript: hex.decode('0020b996bbcda8f3f0bba7b021c9507ec5bf8717bf5d14cbb6bd3d6d1a82defed4ec'),
witnessScript: hex.decode('76a914168b992bcfc44050310b3a94bd0771136d0b28d188ac'),
});
Classic / segwit (pre-taproot) M-of-N Multisig. Doesn't have an address, must be wrapped in P2SH / P2WSH / P2SH-P2WSH.
Duplicate public keys are not accepted to reduce mistakes. Use flag allowSamePubkeys to override the behavior, for cases like 2-of-[A,A,B,C], which can be signed by A or (B and C).
const PubKeys = [
hex.decode('030000000000000000000000000000000000000000000000000000000000000001'),
hex.decode('030000000000000000000000000000000000000000000000000000000000000002'),
hex.decode('030000000000000000000000000000000000000000000000000000000000000003'),
];
// Multisig 2-of-3 wrapped in P2SH
deepStrictEqual(btc.p2sh(btc.p2ms(2, PubKeys)), {
type: 'sh',
address: '3G4AeQtzCLoDAyv2eb3UVTG5atfkyHtuRn',
script: hex.decode('a9149d91c6de4eacde72a7cc86bff98d1915b3c7818f87'),
redeemScript: hex.decode(
'5221030000000000000000000000000000000000000000000000000000000000000001210300000000000000000000000000000000000000000000000000000000000000022103000000000000000000000000000000000000000000000000000000000000000353ae'
),
});
// Multisig 2-of-3 wrapped in P2WSH
deepStrictEqual(btc.p2wsh(btc.p2ms(2, PubKeys)), {
type: 'wsh',
address: 'bc1qwnhzkn8wcyyrnfyfcp7555urssu5dq0rmnvg70hg02z3nxgg4f0qljmr2h',
script: hex.decode('002074ee2b4ceec10839a489c07d4a538384394681e3dcd88f3ee87a85199908aa5e'),
witnessScript: hex.decode(
'5221030000000000000000000000000000000000000000000000000000000000000001210300000000000000000000000000000000000000000000000000000000000000022103000000000000000000000000000000000000000000000000000000000000000353ae'
),
});
// Multisig 2-of-3 wrapped in P2SH-P2WSH
deepStrictEqual(btc.p2sh(btc.p2wsh(btc.p2ms(2, PubKeys))), {
type: 'sh',
address: '3HKWSo57kmcJZ3h43pXS3m5UESR4wXcWTd',
script: hex.decode('a914ab70ab84b12b891364b4b2a14ca813cac308b24287'),
redeemScript: hex.decode('002074ee2b4ceec10839a489c07d4a538384394681e3dcd88f3ee87a85199908aa5e'),
witnessScript: hex.decode(
'5221030000000000000000000000000000000000000000000000000000000000000001210300000000000000000000000000000000000000000000000000000000000000022103000000000000000000000000000000000000000000000000000000000000000353ae'
),
});
// Useful util: wraps P2MS in P2SH or P2WSH
deepStrictEqual(btc.p2sh(btc.p2ms(2, PubKeys)), btc.multisig(2, PubKeys));
deepStrictEqual(btc.p2wsh(btc.p2ms(2, PubKeys)), btc.multisig(2, PubKeys, undefined, true));
// Sorted multisig (BIP67)
deepStrictEqual(btc.p2sh(btc.p2ms(2, PubKeys)), btc.sortedMultisig(2, PubKeys));
deepStrictEqual(btc.p2wsh(btc.p2ms(2, PubKeys)), btc.sortedMultisig(2, PubKeys, true));
TapRoot (SegWit V1) script which replaces both public key and script types from previous versions.
Consumes p2tr(PubKey?, ScriptTree?) and works as PubKey OR ScriptTree, which means
if you use any spendable PubKey and ScriptTree of multi-sig, owner of private key for PubKey will
be able to spend output. If PubKey is undefined we use static unspendable PubKey by default, which leaks information about script type. However, any dynamic unspendable keys will require complex interaction
to sign multi-sig wallets, and there is no BIP/PSBT fields for that yet.
Required tx input fields to make it spendable: tapInternalKey, tapMerkleRoot, tapLeafScript
const PubKey = hex.decode('0101010101010101010101010101010101010101010101010101010101010101');
// Key Path Spend (owned of private key for PubKey can spend)
deepStrictEqual(btc.p2tr(PubKey), {
type: 'tr',
address: 'bc1p7yu5dsly83jg5tkxcljsa30vnpdpl22wr6rty98t6x6p6ekz2gkqzf2t2s',
script: hex.decode('5120f13946c3e43c648a2ec6c7e50ec5ec985a1fa94e1e86b214ebd1b41d66c2522c'),
tweakedPubkey: hex.decode('f13946c3e43c648a2ec6c7e50ec5ec985a1fa94e1e86b214ebd1b41d66c2522c'),
tapInternalKey: hex.decode('0101010101010101010101010101010101010101010101010101010101010101'),
});
const clean = (x) => ({ type: x.type, address: x.address, script: hex.encode(x.script) });
const PubKey2 = hex.decode('0202020202020202020202020202020202020202020202020202020202020202');
const PubKey3 = hex.decode('1212121212121212121212121212121212121212121212121212121212121212');
// Nested P2TR, owner of private key for any of PubKeys can spend whole
// By default P2TR expects binary tree, but btc.p2tr can build it if list of scripts passed.
// Also, you can include {weight: N} to scripts to create differently balanced tree.
deepStrictEqual(
clean(btc.p2tr(undefined, [btc.p2tr_pk(PubKey), btc.p2tr_pk(PubKey2), btc.p2tr_pk(PubKey3)])),
{
type: 'tr',
// weights for bitcoinjs-lib: [3,2,1]
address: 'bc1pj2uvajyygyu2zw0rg0d6yxdsc920kzc5pamfgtlqepe30za922cqjjmkta',
script: '512092b8cec8844138a139e343dba219b0c154fb0b140f76942fe0c873178ba552b0',
}
);
// If scriptsTree is already binary tree, it will be used as-is
deepStrictEqual(
clean(btc.p2tr(undefined, [btc.p2tr_pk(PubKey2), [btc.p2tr_pk(PubKey), btc.p2tr_pk(PubKey3)]])),
{
type: 'tr',
// default weights for bitcoinjs-lib
address: 'bc1pvue6sk9efyvcvpzzqkg8at4qy2u67zj7rj5sfsy573m7alxavqjqucc26a',
script: '51206733a858b9491986044205907eaea022b9af0a5e1ca904c094f477eefcdd6024',
}
);
Taproot N-of-N multisig ([<PubKeys[0:n-1]> CHECKSIGVERIFY] <PubKeys[n-1]> CHECKSIG).
First arg is M, if M!=PubKeys.length, it will create a multi-leaf M-of-N taproot script tree.
This allows one to reveal only M PubKeys on spend, without any information about the others.
This is fast for cases like 15-of-20, but extremely slow for cases like 5-of-20.
Duplicate public keys are not accepted to reduce mistakes. Use flag allowSamePubkeys to override the behavior, for cases like 2-of-[A,A,B,C], which can be signed by A or (B and C).
const PubKey = hex.decode('0101010101010101010101010101010101010101010101010101010101010101');
const PubKey2 = hex.decode('0202020202020202020202020202020202020202020202020202020202020202');
const PubKey3 = hex.decode('1212121212121212121212121212121212121212121212121212121212121212');
// Simple 3-of-3 multisig
// Creates a single script that requires all three pubkeys: [PubKey, PubKey2, PubKey3]
deepStrictEqual(btc.p2tr_ns(3, [PubKey, PubKey2, PubKey3]), [
{
type: 'tr_ns',
script: hex.decode(
'200101010101010101010101010101010101010101010101010101010101010101ad200202020202020202020202020202020202020202020202020202020202020202ad201212121212121212121212121212121212121212121212121212121212121212ac'
),
},
]);
// Simple 2-of-3 multisig
// If M (pubkeys required) is less than N (# of pubkeys), then multiple scripts are created: [[PubKey, PubKey2], [PubKey, PubKey3], [PubKey2, PubKey3]]
const clean = (x) => ({ type: x.type, address: x.address, script: hex.encode(x.script) });
deepStrictEqual(clean(btc.p2tr(undefined, btc.p2tr_ns(2, [PubKey, PubKey2, PubKey3]))), {
type: 'tr',
address: 'bc1pevfcmnkqqq09a4n0fs8c7mwlc6r4efqpvgyqpjvegllavgw235fq3kz7a0',
script: '5120cb138dcec0001e5ed66f4c0f8f6ddfc6875ca401620800c99947ffd621ca8d12',
});
M-of-N single leaf TapRoot multisig (<PubKeys[0]> CHECKSIG [<PubKeys[1:n]> CHECKSIGADD] <M> NUMEQUAL)
Duplicate public keys are not accepted to reduce mistakes. Use flag allowSamePubkeys to override the behavior, for cases like 2-of-[A,A,B,C], which can be signed by A or (B and C).
Experimental, use at your own risk.
const PubKey = hex.decode('0101010101010101010101010101010101010101010101010101010101010101');
const PubKey2 = hex.decode('0202020202020202020202020202020202020202020202020202020202020202');
const PubKey3 = hex.decode('1212121212121212121212121212121212121212121212121212121212121212');
// 2-of-3 TapRoot multisig
deepStrictEqual(btc.p2tr_ms(2, [PubKey, PubKey2, PubKey3]), {
type: 'tr_ms',
script: hex.decode(
'200101010101010101010101010101010101010101010101010101010101010101ac200202020202020202020202020202020202020202020202020202020202020202ba201212121212121212121212121212121212121212121212121212121212121212ba529c'
),
});
// Creates a single script for [PubKey, PubKey2, PubKey3]
const clean = (x) => ({ type: x.type, address: x.address, script: hex.encode(x.script) });
deepStrictEqual(clean(btc.p2tr(undefined, btc.p2tr_ms(2, [PubKey, PubKey2, PubKey3]))), {
type: 'tr',
address: 'bc1p6m2xevckax9zucumnnyvu4xhxem66ugc5r2zlw2a20s0hxnutl8qfef23s',
script: '5120d6d46cb316e98a2e639b9cc8ce54d73677ad7118a0d42fb95d53e0fb9a7c5fce',
});
Specific case of p2tr_ns(1, [pubkey]), which is the same as the BTC descriptor: tr($H,pk(PUBKEY))
const PubKey = hex.decode('0101010101010101010101010101010101010101010101010101010101010101');
// P2PK for taproot
const clean = (x) => ({ type: x.type, address: x.address, script: hex.encode(x.script) });
deepStrictEqual(clean(btc.p2tr(undefined, [btc.p2tr_pk(PubKey)])), {
type: 'tr',
address: 'bc1pfj6w68w3v2f4pkzesc9tsqfvy5znw5qgydwa832v3v83vjn76kdsmr4360',
script: '51204cb4ed1dd1629350d859860ab8012c2505375008235dd3c54c8b0f164a7ed59b',
});
We support both PSBTv0 and draft PSBTv2 (there is no PSBTv1). If PSBTv2 transaction is encoded into PSBTv1, all PSBTv2 fields will be stripped.
We strip 'unknown' keys inside PSBT, they needed for new version/features support, however any unsupported feature/new version can significantly break assumptions about code. If you have use-case where they are needed, create a github issue.
PSBTv2 features tx_modifiable and taproot+bip32 are not supported yet.
// Decode
Transaction.fromRaw(raw: Bytes, opts: TxOpts = {}); // Raw tx
Transaction.fromPSBT(psbt: Bytes, opts: TxOpts = {}); // PSBT tx
// Encode
tx.unsignedTx; // Bytes of raw unsigned tx
tx.hex; // hex encoded signed raw tx
tx.toPSBT(ver = this.PSBTVersion); // PSBT
We have txid (BE) instead of hash (LE) in transactions. We can support both, but txid is consistent across block explorers, while some explorers treat hash as txid - so hash is not consistent.
Use getInput and inputsLength to read information about inputs: they return a copy.
This is necessary to avoid accidental modification of internal structures without calling methods (addInput/updateInput) that will verify correctness.
type TransactionInput = {
txid?: Bytes,
index?: number,
nonWitnessUtxo?: <RawTransactionBytesOrHex>,
witnessUtxo?: {script?: Bytes; amount: bigint},
partialSig?: [Bytes, Bytes][]; // [PubKey, Signature]
sighashType?: P.U32LE,
redeemScript?: Bytes,
witnessScript?: Bytes,
bip32Derivation?: [Bytes, {fingerprint: number; path: number[]}]; // [PubKey, DeriviationPath]
finalScriptSig?: Bytes,
finalScriptWitness?: Bytes[],
porCommitment?: Bytes,
sequence?: number,
requiredTimeLocktime?: number,
requiredHeightLocktime?: number,
tapKeySig?: Bytes,
tapScriptSig?: [Bytes, Bytes][]; // [PubKeySchnorr, LeafHash]
// [ControlBlock, ScriptWithVersion]
tapLeafScript?: [{version: number; internalKey: Bytes; merklePath: Bytes[]}, Bytes];
tapInternalKey?: Bytes,
tapMerkleRoot?: Bytes,
};
tx.addInput(input: TransactionInput): number;
tx.updateInput(idx: number, input: TransactionInput);
// Input
tx.addInput({ txid: new Uint8Array(32), index: 0 });
deepStrictEqual(tx.inputs[0], {
txid: new Uint8Array(32),
index: 0,
sequence: btc.DEFAULT_SEQUENCE,
});
// Update basic value
tx.updateInput(0, { index: 10 });
deepStrictEqual(tx.inputs[0], {
txid: new Uint8Array(32),
index: 10,
sequence: btc.DEFAULT_SEQUENCE,
});
// Add value as hex
tx.addInput({
txid: '0000000000000000000000000000000000000000000000000000000000000000',
index: 0,
});
deepStrictEqual(tx.inputs[2], {
txid: new Uint8Array(32),
index: 0,
sequence: btc.DEFAULT_SEQUENCE,
});
// Update key map
const pubKey = hex.decode('030000000000000000000000000000000000000000000000000000000000000001');
const bip1 = [pubKey, { fingerprint: 5, path: [1, 2, 3] }];
const pubKey2 = hex.decode('030000000000000000000000000000000000000000000000000000000000000002');
const bip2 = [pubKey2, { fingerprint: 6, path: [4, 5, 6] }];
const pubKey3 = hex.decode('030000000000000000000000000000000000000000000000000000000000000003');
const bip3 = [pubKey3, { fingerprint: 7, path: [7, 8, 9] }];
// Add K-V
tx.updateInput(0, { bip32Derivation: [bip1] });
deepStrictEqual(tx.inputs[0].bip32Derivation, [bip1]);
// Add another K-V
tx.updateInput(0, { bip32Derivation: [bip2] });
deepStrictEqual(tx.inputs[0].bip32Derivation, [bip1, bip2]);
// Delete K-V
tx.updateInput(0, { bip32Derivation: [[pubKey, undefined]] });
deepStrictEqual(tx.inputs[0].bip32Derivation, [bip2]);
// Second add of same k-v does nothing
tx.updateInput(0, { bip32Derivation: [bip2] });
deepStrictEqual(tx.inputs[0].bip32Derivation, [bip2]);
// Second add of k-v with different value breaks
throws(() => tx.updateInput(0, { bip32Derivation: [[pubKey2, bip1[1]]] }));
tx.updateInput(0, { bip32Derivation: [bip1, bip2, bip3] });
// Preserves order (re-ordered on PSBT encoding)
deepStrictEqual(tx.inputs[0].bip32Derivation, [bip2, bip1, bip3]);
// PSBT encoding re-order k-v
const tx2 = btc.Transaction.fromPSBT(tx.toPSBT());
deepStrictEqual(tx2.inputs[0].bip32Derivation, [bip1, bip2, bip3]);
// Remove field
tx.updateInput(0, { bip32Derivation: undefined });
deepStrictEqual(tx.inputs[0], {
txid: new Uint8Array(32),
index: 10,
sequence: btc.DEFAULT_SEQUENCE,
});
// Read inputs
for (let i = 0; i < tx.inputsLength; i++) {
console.log('I', tx.getInput(i));
}
addOutputAddress uses bigint amounts, which means satoshis - NOT btc. If you need btc representation, use Decimal:
const amountSatoshi = btc.Decimal.decode('1.5'); // 1.5 btc in satoshi
Use getOutput and outputsLength to read outputs information. This methods returns copy of output, instead of internal representation.
This is necessary to avoid accidental modification of internal structures without calling methods (addOutput/updateOutput) that will verify correctness.
type TransactionOutput = {
script?: Bytes,
amount?: bigint,
redeemScript?: Bytes,
witnessScript?: Bytes,
bip32Derivation?: [Bytes, {fingerprint: number; path: number[]}]; // [PubKey, DeriviationPath]
tapInternalKey?: Bytes,
};
tx.addOutput(o: TransactionOutput): number;
tx.updateOutput(idx: number, output: TransactionOutput);
tx.addOutputAddress(address: string, amount: bigint, network = NETWORK): number;
const compressed = hex.decode(
'030000000000000000000000000000000000000000000000000000000000000001'
);
const script = btc.p2pkh(compressed).script;
tx.addOutput({ script, amount: 100n });
deepStrictEqual(tx.outputs[0], {
script,
amount: 100n,
});
// Update basic value
tx.updateOutput(0, { amount: 200n });
deepStrictEqual(tx.outputs[0], {
script,
amount: 200n,
});
// Add K-V
tx.updateOutput(0, { bip32Derivation: [bip1] });
deepStrictEqual(tx.outputs[0].bip32Derivation, [bip1]);
// Add another K-V
tx.updateOutput(0, { bip32Derivation: [bip2] });
deepStrictEqual(tx.outputs[0].bip32Derivation, [bip1, bip2]);
// Delete K-V
tx.updateOutput(0, { bip32Derivation: [[pubKey, undefined]] });
deepStrictEqual(tx.outputs[0].bip32Derivation, [bip2]);
// Second add of same k-v does nothing
tx.updateOutput(0, { bip32Derivation: [bip2] });
deepStrictEqual(tx.outputs[0].bip32Derivation, [bip2]);
// Second add of k-v with different value breaks
throws(() => tx.updateOutput(0, { bip32Derivation: [[pubKey2, bip1[1]]] }));
tx.updateOutput(0, { bip32Derivation: [bip1, bip2, bip3] });
// Preserves order (re-ordered on PSBT encoding)
deepStrictEqual(tx.outputs[0].bip32Derivation, [bip2, bip1, bip3]);
// PSBT encoding re-order k-v
const tx3 = btc.Transaction.fromPSBT(tx.toPSBT());
deepStrictEqual(tx3.outputs[0].bip32Derivation, [bip1, bip2, bip3]);
// Remove field
tx.updateOutput(0, { bip32Derivation: undefined });
deepStrictEqual(tx.outputs[0], {
script,
amount: 200n,
});
// Read outputs
for (let i = 0; i < tx.outputsLength; i++) {
console.log('O', tx.getOutput(i));
}
const privKey = hex.decode('0101010101010101010101010101010101010101010101010101010101010101');
const txP2WPKH = new btc.Transaction();
for (const inp of TX_TEST_INPUTS) {
txP2WPKH.addInput({
txid: inp.txid,
index: inp.index,
witnessUtxo: {
amount: inp.amount,
script: btc.p2wpkh(secp256k1.getPublicKey(privKey, true)).script,
},
});
}
for (const [address, amount] of TX_TEST_OUTPUTS) txP2WPKH.addOutputAddress(address, amount);
deepStrictEqual(hex.encode(txP2WPKH.unsignedTx), RAW_TX_HEX);
txP2WPKH.sign(privKey);
txP2WPKH.finalize();
deepStrictEqual(txP2WPKH.id, 'cbb94443b19861df0824914fa654212facc071854e0df6f7388b482a6394526d');
deepStrictEqual(
txP2WPKH.hex,
'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'
);
const testnet = {
wif: 0xef,
bip32: {
public: 0x043587cf,
private: 0x04358394,
},
};
// The private keys in the tests below are derived from the following master private key:
const epriv =
'tprv8ZgxMBicQKsPd9TeAdPADNnSyH9SSUUbTVeFszDE23Ki6TBB5nCefAdHkK8Fm3qMQR6sHwA56zqRmKmxnHk37JkiFzvncDqoKmPWubu7hDF';
const hdkey = bip32.HDKey.fromExtendedKey(epriv, testnet.bip32);
// const seed = 'cUkG8i1RFfWGWy5ziR11zJ5V4U4W3viSFCfyJmZnvQaUsd1xuF3T';
const tx = new btc.Transaction();
// A creator creating a PSBT for a transaction which creates the following outputs:
tx.addOutput({
script: '0014d85c2b71d0060b09c9886aeb815e50991dda124d',
amount: btc.Decimal.decode('1.49990000'),
});
tx.addOutput({
script: '001400aea9a2e5f0f876a588df5546e8742d1d87008f',
amount: btc.Decimal.decode('1.00000000'),
});
// and spends the following inputs:
tx.addInput({
txid: '75ddabb27b8845f5247975c8a5ba7c6f336c4570708ebe230caf6db5217ae858',
index: 0,
});
tx.addInput({
txid: '1dea7cd05979072a3578cab271c02244ea8a090bbb46aa680a65ecd027048d83',
index: 1,
});
// must create this PSBT:
const psbt1 = tx.toPSBT();
// Given the above PSBT, an updater with only the following:
const tx2 = btc.Transaction.fromPSBT(psbt1);
tx2.updateInput(0, {
nonWitnessUtxo:
'0200000001aad73931018bd25f84ae400b68848be09db706eac2ac18298babee71ab656f8b0000000048473044022058f6fc7c6a33e1b31548d481c826c015bd30135aad42cd67790dab66d2ad243b02204a1ced2604c6735b6393e5b41691dd78b00f0c5942fb9f751856faa938157dba01feffffff0280f0fa020000000017a9140fb9463421696b82c833af241c78c17ddbde493487d0f20a270100000017a91429ca74f8a08f81999428185c97b5d852e4063f618765000000',
redeemScript:
'5221029583bf39ae0a609747ad199addd634fa6108559d6c5cd39b4c2183f1ab96e07f2102dab61ff49a14db6a7d02b0cd1fbb78fc4b18312b5b4e54dae4dba2fbfef536d752ae',
bip32Derivation: [
[
'029583bf39ae0a609747ad199addd634fa6108559d6c5cd39b4c2183f1ab96e07f',
{ fingerprint: hdkey.fingerprint, path: btc.bip32Path("m/0'/0'/0'") },
],
[
'02dab61ff49a14db6a7d02b0cd1fbb78fc4b18312b5b4e54dae4dba2fbfef536d7',
{ fingerprint: hdkey.fingerprint, path: btc.bip32Path("m/0'/0'/1'") },
],
],
});
tx2.updateInput(1, {
// use witness utxo ({script, amount})
witnessUtxo: btc.RawTx.decode(
hex.decode(
'0200000000010158e87a21b56daf0c23be8e7070456c336f7cbaa5c8757924f545887bb2abdd7501000000171600145f275f436b09a8cc9a2eb2a2f528485c68a56323feffffff02d8231f1b0100000017a914aed962d6654f9a2b36608eb9d64d2b260db4f1118700c2eb0b0000000017a914b7f5faf40e3d40a5a459b1db3535f2b72fa921e88702483045022100a22edcc6e5bc511af4cc4ae0de0fcd75c7e04d8c1c3a8aa9d820ed4b967384ec02200642963597b9b1bc22c75e9f3e117284a962188bf5e8a74c895089046a20ad770121035509a48eb623e10aace8bfd0212fdb8a8e5af3c94b0b133b95e114cab89e4f7965000000'
)
).outputs[1],
redeemScript: '00208c2353173743b595dfb4a07b72ba8e42e3797da74e87fe7d9d7497e3b2028903',
witnessScript:
'522103089dc10c7ac6db54f91329af617333db388cead0c231f723379d1b99030b02dc21023add904f3d6dcf59ddb906b0dee23529b7ffb9ed50e5e86151926860221f0e7352ae',
bip32Derivation: [
[
'03089dc10c7ac6db54f91329af617333db388cead0c231f723379d1b99030b02dc',
{ fingerprint: hdkey.fingerprint, path: btc.bip32Path("m/0'/0'/2'") },
],
[
'023add904f3d6dcf59ddb906b0dee23529b7ffb9ed50e5e86151926860221f0e73',
{ fingerprint: hdkey.fingerprint, path: btc.bip32Path("m/0'/0'/3'") },
],
],
});
tx2.updateOutput(0, {
bip32Derivation: [
[
'03a9a4c37f5996d3aa25dbac6b570af0650394492942460b354753ed9eeca58771',
{ fingerprint: hdkey.fingerprint, path: btc.bip32Path("m/0'/0'/4'") },
],
],
});
tx2.updateOutput(1, {
bip32Derivation: [
[
'027f6399757d2eff55a136ad02c684b1838b6556e5f1b6b34282a94b6b50051096',
{ fingerprint: hdkey.fingerprint, path: btc.bip32Path("m/0'/0'/5'") },
],
],
});
// Must create this PSBT:
const psbt2 = tx2.toPSBT();
// An updater which adds SIGHASH_ALL to the above PSBT must create this PSBT:
const tx3 = btc.Transaction.fromPSBT(psbt2);
for (let i = 0; i < tx3.inputs.length; i++) tx3.updateInput(i, { sighashType: btc.SigHash.ALL });
const psbt3 = tx3.toPSBT();
/*
Given the above updated PSBT, a signer that supports SIGHASH_ALL for P2PKH and P2WPKH spends and uses RFC6979 for nonce generation and has the following keys:
- cP53pDbR5WtAD8dYAW9hhTjuvvTVaEiQBdrz9XPrgLBeRFiyCbQr (m/0'/0'/0')
- cR6SXDoyfQrcp4piaiHE97Rsgta9mNhGTen9XeonVgwsh4iSgw6d (m/0'/0'/2')
*/
// We don't use HDKey, because it will everything because of bip32 derivation
const tx4 = btc.Transaction.fromPSBT(psbt3);
tx4.sign(btc.WIF(testnet).decode('cP53pDbR5WtAD8dYAW9hhTjuvvTVaEiQBdrz9XPrgLBeRFiyCbQr'));
tx4.sign(btc.WIF(testnet).decode('cR6SXDoyfQrcp4piaiHE97Rsgta9mNhGTen9XeonVgwsh4iSgw6d'));
// must create this PSBT:
const psbt4 = tx4.toPSBT();
// Given the above updated PSBT, a signer with the following keys:
// cT7J9YpCwY3AVRFSjN6ukeEeWY6mhpbJPxRaDaP5QTdygQRxP9Au (m/0'/0'/1')
// cNBc3SWUip9PPm1GjRoLEJT6T41iNzCYtD7qro84FMnM5zEqeJsE (m/0'/0'/3')
const tx5 = btc.Transaction.fromPSBT(psbt3);
tx5.sign(btc.WIF(testnet).decode('cT7J9YpCwY3AVRFSjN6ukeEeWY6mhpbJPxRaDaP5QTdygQRxP9Au'));
tx5.sign(btc.WIF(testnet).decode('cNBc3SWUip9PPm1GjRoLEJT6T41iNzCYtD7qro84FMnM5zEqeJsE'));
// must create this PSBT:
const psbt5 = tx5.toPSBT();
// Given both of the above PSBTs, a combiner must create this PSBT:
const psbt6 = btc.PSBTCombine([psbt4, psbt5]);
// Given the above PSBT, an input finalizer must create this PSBT:
const tx7 = btc.Transaction.fromPSBT(psbt6);
tx7.finalize();
const psbt7 = tx7.toPSBT();
// Given the above PSBT, a transaction extractor must create this Bitcoin transaction:
const tx8 = btc.Transaction.fromPSBT(psbt7);
deepStrictEqual(
tx8.extract(),
hex.decode(
'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'
)
);
UTXO selection is the process of choosing which UTXOs to use as inputs when making an on-chain bitcoin payment. The library:
Taproot estimation is precise, but you have to pass sighash if you want to use non-default one, because it changes signature size. For complex taproot trees you need to filter tapLeafScript to include only leafs which you can sign we estimate size with smallest leaf (same as finalization), but in specific case keys for this leaf can be unavailable (complex multisig)
Oldest / Newest expects UTXO provided in historical order (oldest first),
otherwise we have no way to detect age of tx.
Strategy selection is complicated. Best should be: exactBiggest/accumSmallest.
exactBiggest/accumBiggest creates tx with smallest fees,
but it breaks big outputs to small ones, which in the end will create
a lot of outputs close to dust.
default: good for privacy, same as exactBiggest/accumBiggestall: send all coins to change address (consolidation)accum: accumulates inputs until the target value (+fees) is reached, skipping detrimental inputsexact: accumulates inputs until the target value (+fees) is matched, does not accumulate inputs
that go over the target value (within a threshold)accumNewestaccumOldestaccumSmallestaccumBiggestexactNewest/accumNewestexactNewest/accumOldestexactNewest/accumSmallestexactNewest/accumBiggestexactOldest/accumNewestexactOldest/accumOldestexactOldest/accumSmallestexactOldest/accumBiggestexactSmallest/accumNewestexactSmallest/accumOldestexactSmallest/accumSmallestexactSmallest/accumBiggestexactBiggest/accumNewestexactBiggest/accumOldestexactBiggest/accumSmallestexactBiggest/accumBiggestconst privKey = hex.decode('0101010101010101010101010101010101010101010101010101010101010101');
const pubKey = secp256k1.getPublicKey(privKey, true);
const spend = btc.p2wpkh(pubKey, regtest);
const utxo = [
{
...spend, // add witness/redeem scripts from spend
// Get txid, index from explorer/network
txid: hex.decode('0af50a00a22f74ece24c12cd667c290d3a35d48124a69f4082700589172a3aa2'),
index: 0,
// utxo tx information
// script can be used from spend itself or from explorer
witnessUtxo: { script: spend.script, amount: 100_000n }, // value in satoshi
},
{
...spend,
txid: hex.decode('0af50a00a22f74ece24c12cd667c290d3a35d48124a69f4082700589172a3aa2'),
index: 1,
witnessUtxo: { script: spend.script, amount: btc.Decimal.decode('1.5') }, // value in btc
},
// {
// ...spend,
// txid: hex.decode('75ddabb27b8845f5247975c8a5ba7c6f336c4570708ebe230caf6db5217ae858'),
// index: 0,
// // tx hex from blockchain (required for non-SegWit UTXO)
// nonWitnessUtxo: hex.decode(
// '0200000001aad73931018bd25f84ae400b68848be09db706eac2ac18298babee71ab656f8b0000000048473044022058f6fc7c6a33e1b31548d481c826c015bd30135aad42cd67790dab66d2ad243b02204a1ced2604c6735b6393e5b41691dd78b00f0c5942fb9f751856faa938157dba01feffffff0280f0fa020000000017a9140fb9463421696b82c833af241c78c17ddbde493487d0f20a270100000017a91429ca74f8a08f81999428185c97b5d852e4063f618765000000'
// ),
// },
];
const outputs = [
{ address: '2MvpbAgedBzJUBZWesDwdM7p3FEkBEwq3n3', amount: 50_000n }, // amount in satoshi
{
address: 'bcrt1pw53jtgez0wf69n06fchp0ctk48620zdscnrj8heh86wykp9mv20q7vd3gm',
amount: btc.Decimal.decode('0.5'), // amount in btc
},
];
// Send all utxo to specific address (consolidation):
// const selected = btc.selectUTXO(utxo, [], 'all', {
// changeAddress: 'bcrt1pea3850rzre54e53eh7suwmrwc66un6nmu9npd7eqrhd6g4lh8uqsxcxln8', ...
const selected = btc.selectUTXO(utxo, outputs, 'default', {
changeAddress: 'bcrt1pea3850rzre54e53eh7suwmrwc66un6nmu9npd7eqrhd6g4lh8uqsxcxln8', // required, address to send change
feePerByte: 2n, // require, fee per vbyte in satoshi
bip69: true, // lexicographical Indexing of Transaction Inputs and Outputs
createTx: true, // create tx with selected inputs/outputs
network: regtest,
});
// NOTE: 'selected' will 'undefined' if there is not enough funds
deepStrictEqual(selected.fee, 394n); // estimated fee
deepStrictEqual(selected.change, true); // change address used
deepStrictEqual(selected.outputs, [
{ address: '2MvpbAgedBzJUBZWesDwdM7p3FEkBEwq3n3', amount: 50000n },
{
address: 'bcrt1pw53jtgez0wf69n06fchp0ctk48620zdscnrj8heh86wykp9mv20q7vd3gm',
amount: 50_000_000n,
},
// Change address
// NOTE: with bip69 it is not necessarily last item in outputs
{
address: 'bcrt1pea3850rzre54e53eh7suwmrwc66un6nmu9npd7eqrhd6g4lh8uqsxcxln8',
amount: 99_949_606n,
},
]);
// No need to create tx manually!
const { tx } = selected;
tx.sign(privKey);
tx.finalize();
deepStrictEqual(tx.id, 'b702078d65edd65a84b2a97a669df5631b06f42a67b0d7090e540b02cc65aed5');
// real tx fee, can be bigger than estimated, since we expect signatures of maximal size
deepStrictEqual(tx.fee, 394n);
We support custom scripts. You can pass it as last argument to p2tr.
We've developed separate micro-ordinals package, which contains:
import { pubSchnorr, signSchnorr } from '@scure/btc-signer/utils';
import { pubECDSA, signECDSA } from '@scure/btc-signer/utils';
import { randomPrivateKeyBytes } from '@scure/btc-signer/utils';
const priv = randomPrivateKeyBytes();
const pub = pubSchnorr(priv);
Returns common addresses from privateKey
const privKey = hex.decode('0101010101010101010101010101010101010101010101010101010101010101');
deepStrictEqual(btc.getAddress('pkh', privKey), '1C6Rc3w25VHud3dLDamutaqfKWqhrLRTaD'); // P2PKH (legacy address)
deepStrictEqual(btc.getAddress('wpkh', privKey), 'bc1q0xcqpzrky6eff2g52qdye53xkk9jxkvrh6yhyw'); // SegWit V0 address
deepStrictEqual(
btc.getAddress('tr', priv),
'bc1p33wm0auhr9kkahzd6l0kqj85af4cswn276hsxg6zpz85xe2r0y8syx4e5t'
); // TapRoot KeyPathSpend
Encoding/decoding of WIF privateKeys. Only compressed keys are supported for now.
const privKey = hex.decode('0101010101010101010101010101010101010101010101010101010101010101');
deepStrictEqual(btc.WIF().encode(privKey), 'KwFfNUhSDaASSAwtG7ssQM1uVX8RgX5GHWnnLfhfiQDigjioWXHH');
deepStrictEqual(
hex.encode(btc.WIF().decode('KwFfNUhSDaASSAwtG7ssQM1uVX8RgX5GHWnnLfhfiQDigjioWXHH')),
'0101010101010101010101010101010101010101010101010101010101010101'
);
Encoding/decoding bitcoin scripts
deepStrictEqual(
btc.Script.decode(
hex.decode(
'5221030000000000000000000000000000000000000000000000000000000000000001210300000000000000000000000000000000000000000000000000000000000000022103000000000000000000000000000000000000000000000000000000000000000353ae'
)
).map((i) => (P.isBytes(i) ? hex.encode(i) : i)),
[
'OP_2',
'030000000000000000000000000000000000000000000000000000000000000001',
'030000000000000000000000000000000000000000000000000000000000000002',
'030000000000000000000000000000000000000000000000000000000000000003',
'OP_3',
'CHECKMULTISIG',
]
);
deepStrictEqual(
hex.encode(
btc.Script.encode([
'OP_2',
hex.decode('030000000000000000000000000000000000000000000000000000000000000001'),
hex.decode('030000000000000000000000000000000000000000000000000000000000000002'),
hex.decode('030000000000000000000000000000000000000000000000000000000000000003'),
'OP_3',
'CHECKMULTISIG',
])
),
'5221030000000000000000000000000000000000000000000000000000000000000001210300000000000000000000000000000000000000000000000000000000000000022103000000000000000000000000000000000000000000000000000000000000000353ae'
);
Encoding / decoding of output scripts
deepStrictEqual(
btc.OutScript.decode(
hex.decode(
'5221030000000000000000000000000000000000000000000000000000000000000001210300000000000000000000000000000000000000000000000000000000000000022103000000000000000000000000000000000000000000000000000000000000000353ae'
)
),
{
type: 'ms',
m: 2,
pubkeys: [
'030000000000000000000000000000000000000000000000000000000000000001',
'030000000000000000000000000000000000000000000000000000000000000002',
'030000000000000000000000000000000000000000000000000000000000000003',
].map(hex.decode),
}
);
deepStrictEqual(
hex.encode(
btc.OutScript.encode({
type: 'ms',
m: 2,
pubkeys: [
'030000000000000000000000000000000000000000000000000000000000000001',
'030000000000000000000000000000000000000000000000000000000000000002',
'030000000000000000000000000000000000000000000000000000000000000003',
].map(hex.decode),
})
),
'5221030000000000000000000000000000000000000000000000000000000000000001210300000000000000000000000000000000000000000000000000000000000000022103000000000000000000000000000000000000000000000000000000000000000353ae'
);
The library has been independently audited:
UTXO selection functionality has not been audited yet. Commit 58d4554 split the library from one into several files to ease future maintainability.
npm-diffWe consider infrastructure attacks like rogue NPM modules very important; that's why it's crucial to minimize the amount of 3rd-party dependencies & native bindings. If your app uses 500 dependencies, any dep could get hacked and you'll be downloading malware with every install. Our goal is to minimize this attack vector.
If you see anything unusual: investigate and report.
MIT (c) Paul Miller (https://paulmillr.com), see LICENSE file.
FAQs
Audited & minimal library for Bitcoin. Handle transactions, Schnorr, Taproot, UTXO & PSBT
We found that @scure/btc-signer demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 0 open source maintainers collaborating on the project.
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