@bsv/sdk
Version:
BSV Blockchain Software Development Kit
155 lines • 6.54 kB
JavaScript
import Signature from './Signature.js';
import BigNumber from './BigNumber.js';
import * as Hash from './Hash.js';
import { toArray, Writer } from './utils.js';
export default class TransactionSignature extends Signature {
static SIGHASH_ALL = 0x00000001;
static SIGHASH_NONE = 0x00000002;
static SIGHASH_SINGLE = 0x00000003;
static SIGHASH_FORKID = 0x00000040;
static SIGHASH_ANYONECANPAY = 0x00000080;
scope;
static format(params) {
const currentInput = {
sourceTXID: params.sourceTXID,
sourceOutputIndex: params.sourceOutputIndex,
sequence: params.inputSequence
};
const inputs = [...params.otherInputs];
inputs.splice(params.inputIndex, 0, currentInput);
const getPrevoutHash = () => {
const writer = new Writer();
for (const input of inputs) {
if (typeof input.sourceTXID === 'undefined') {
if (input.sourceTransaction == null) {
throw new Error('Missing sourceTransaction for input');
}
writer.write(input.sourceTransaction.hash());
}
else {
writer.writeReverse(toArray(input.sourceTXID, 'hex'));
}
writer.writeUInt32LE(input.sourceOutputIndex);
}
const buf = writer.toArray();
const ret = Hash.hash256(buf);
return ret;
};
const getSequenceHash = () => {
const writer = new Writer();
for (const input of inputs) {
const sequence = input.sequence ?? 0xffffffff; // Default to max sequence number
writer.writeUInt32LE(sequence);
}
const buf = writer.toArray();
const ret = Hash.hash256(buf);
return ret;
};
function getOutputsHash(outputIndex) {
const writer = new Writer();
if (typeof outputIndex === 'undefined') {
for (const output of params.outputs) {
const satoshis = output.satoshis ?? 0; // Default to 0 if undefined
writer.writeUInt64LE(satoshis);
const script = output.lockingScript?.toBinary() ?? [];
writer.writeVarIntNum(script.length);
writer.write(script);
}
}
else {
const output = params.outputs[outputIndex];
if (output === undefined) { // ✅ Explicitly check for undefined
throw new Error(`Output at index ${outputIndex} does not exist`);
}
const satoshis = output.satoshis ?? 0; // Default to 0 if undefined
writer.writeUInt64LE(satoshis);
const script = output.lockingScript?.toBinary() ?? [];
writer.writeVarIntNum(script.length);
writer.write(script);
}
const buf = writer.toArray();
const ret = Hash.hash256(buf);
return ret;
}
let hashPrevouts = new Array(32).fill(0);
let hashSequence = new Array(32).fill(0);
let hashOutputs = new Array(32).fill(0);
if ((params.scope & TransactionSignature.SIGHASH_ANYONECANPAY) === 0) {
hashPrevouts = getPrevoutHash();
}
if ((params.scope & TransactionSignature.SIGHASH_ANYONECANPAY) === 0 &&
(params.scope & 31) !== TransactionSignature.SIGHASH_SINGLE &&
(params.scope & 31) !== TransactionSignature.SIGHASH_NONE) {
hashSequence = getSequenceHash();
}
if ((params.scope & 31) !== TransactionSignature.SIGHASH_SINGLE &&
(params.scope & 31) !== TransactionSignature.SIGHASH_NONE) {
hashOutputs = getOutputsHash();
}
else if ((params.scope & 31) === TransactionSignature.SIGHASH_SINGLE &&
params.inputIndex < params.outputs.length) {
hashOutputs = getOutputsHash(params.inputIndex);
}
const writer = new Writer();
// Version
writer.writeInt32LE(params.transactionVersion);
// Input prevouts/nSequence (none/all, depending on flags)
writer.write(hashPrevouts);
writer.write(hashSequence);
// outpoint (32-byte hash + 4-byte little endian)
writer.writeReverse(toArray(params.sourceTXID, 'hex'));
writer.writeUInt32LE(params.sourceOutputIndex);
// scriptCode of the input (serialized as scripts inside CTxOuts)
const subscriptBin = params.subscript.toBinary();
writer.writeVarIntNum(subscriptBin.length);
writer.write(subscriptBin);
// value of the output spent by this input (8-byte little endian)
writer.writeUInt64LE(params.sourceSatoshis);
// nSequence of the input (4-byte little endian)
const sequenceNumber = currentInput.sequence;
writer.writeUInt32LE(sequenceNumber);
// Outputs (none/one/all, depending on flags)
writer.write(hashOutputs);
// Locktime
writer.writeUInt32LE(params.lockTime);
// sighashType
writer.writeUInt32LE(params.scope >>> 0);
const buf = writer.toArray();
return buf;
}
// The format used in a tx
static fromChecksigFormat(buf) {
if (buf.length === 0) {
// allow setting a "blank" signature
const r = new BigNumber(1);
const s = new BigNumber(1);
const scope = 1;
return new TransactionSignature(r, s, scope);
}
const scope = buf[buf.length - 1];
const derbuf = buf.slice(0, buf.length - 1);
const tempSig = Signature.fromDER(derbuf);
return new TransactionSignature(tempSig.r, tempSig.s, scope);
}
constructor(r, s, scope) {
super(r, s);
this.scope = scope;
}
/**
* Compares to bitcoind's IsLowDERSignature
* See also Ecdsa signature algorithm which enforces this.
* See also Bip 62, "low S values in signatures"
*/
hasLowS() {
if (this.s.ltn(1) ||
this.s.gt(new BigNumber('7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0', 'hex'))) {
return false;
}
return true;
}
toChecksigFormat() {
const derbuf = this.toDER();
return [...derbuf, this.scope];
}
}
//# sourceMappingURL=TransactionSignature.js.map