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Add replaceInput to Transaction
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@MatthewLM
MatthewLM committed Oct 27, 2023
1 parent 097dc3d commit 2085b1b
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Showing 2 changed files with 230 additions and 33 deletions.
60 changes: 50 additions & 10 deletions coinlib/lib/src/tx/transaction.dart
View file
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ import 'package:coinlib/src/crypto/ec_private_key.dart';
import 'package:coinlib/src/crypto/hash.dart';
import 'package:coinlib/src/tx/inputs/taproot_key_input.dart';
import 'inputs/input.dart';
import 'inputs/input_signature.dart';
import 'inputs/legacy_input.dart';
import 'inputs/legacy_witness_input.dart';
import 'inputs/raw_input.dart';
Expand Down Expand Up @@ -184,7 +185,9 @@ class Transaction with Writable {

/// Sign the input at [inputN] with the [key] and [hashType] and return a new
/// [Transaction] with the signed input. The input must be a signable
/// P2PKH, P2WPKH or P2SH multisig input or [CannotSignInput] will be thrown.
/// [P2PKHInput], [P2WPKHInput], [P2SHMultisigInput] or [TaprootKeyInput].
/// Otherwise [CannotSignInput] will be thrown. Other inputs may be signed
/// seperately and inserted back into the transaction via [replaceInput].
/// [value] is only required for P2WPKH.
/// [prevOuts] is only required for Taproot inputs.
Transaction sign({
Expand Down Expand Up @@ -271,25 +274,62 @@ class Transaction with Writable {

}

/// Returns a new [Transaction] with the [input] added to the end of the input
/// list.
Transaction addInput(Input input) {

// For existing inputs, remove any signatures without ANYONECANPAY
final modifiedInputs = inputs.map(
(input) => input.filterSignatures((insig) => insig.hashType.anyOneCanPay),
);
/// Replaces the input at [n] with the new [input] and invalidates other
/// input signatures that have standard sighash types accordingly. This is
/// useful for signing or otherwise updating inputs that cannot be signed with
/// the [sign] method.
Transaction replaceInput(Input input, int n) {

final oldInput = inputs[n];

if (input == oldInput) return this;

final newPrevOut = input.prevOut != oldInput.prevOut;
final newSequence = input.sequence != oldInput.sequence;

final filtered = inputs.map(
(input) => input.filterSignatures(
(insig)
// Allow ANYONECANPAY
=> insig.hashType.anyOneCanPay
// Allow signature if previous output hasn't changed and the sequence
// has not changed for taproot inputs or when using SIGHASH_ALL.
|| !(
newPrevOut || (
newSequence
&& (insig.hashType.all || insig is SchnorrInputSignature)
)
),
),
).toList();

// Add new input to end of inputs of new transaction
return Transaction(
version: version,
inputs: [...modifiedInputs, input],
inputs: [...filtered.take(n), input, ...filtered.sublist(n+1)],
outputs: outputs,
locktime: locktime,
);

}

/// Returns a new [Transaction] with the [input] added to the end of the input
/// list.
Transaction addInput(Input input) => Transaction(
version: version,
inputs: [
// Only keep ANYONECANPAY signatures when adding a new input
...inputs.map(
(input) => input.filterSignatures(
(insig) => insig.hashType.anyOneCanPay,
),
),
input,
],
outputs: outputs,
locktime: locktime,
);

/// Returns a new [Transaction] with the [output] added to the end of the
/// output list.
Transaction addOutput(Output output) {
Expand Down
203 changes: 180 additions & 23 deletions coinlib/test/tx/transaction_test.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,8 @@ void main() {

setUpAll(loadCoinlib);

final keyVec = keyPairVectors[0];

expectVectorWithoutObj(Transaction tx, TxVector vec) {
expect(tx.toHex(), vec.hex);

Expand Down Expand Up @@ -306,9 +308,6 @@ void main() {
expect(() => tx.outputs[0] = exampleOutput, throwsA(anything));
});


final keyVec = keyPairVectors[0];

test("sign P2PKH", () {

expectP2PKH({
Expand Down Expand Up @@ -592,33 +591,191 @@ void main() {

});

});
test("invalid SIGHASH_SINGLE when adding corresponding output", () {

test("invalid SIGHASH_SINGLE when adding corresponding output", () {
final privkey = ECPrivateKey.generate();
final pubkey = privkey.pubkey;

final privkey = ECPrivateKey.generate();
final pubkey = privkey.pubkey;
var tx = Transaction(
inputs: [
P2PKHInput(prevOut: examplePrevOut, publicKey: pubkey),
P2PKHInput(prevOut: examplePrevOut, publicKey: pubkey),
],
outputs: [exampleOutput],
);

var tx = Transaction(
inputs: [
P2PKHInput(prevOut: examplePrevOut, publicKey: pubkey),
P2PKHInput(prevOut: examplePrevOut, publicKey: pubkey),
],
outputs: [exampleOutput],
);
for (int i = 0; i < 2; i++) {
expect(tx.complete, false);
tx = tx.sign(inputN: i, key: privkey, hashType: SigHashType.single());
}

for (int i = 0; i < 2; i++) {
expect(tx.complete, true);
tx = tx.addOutput(exampleOutput);
expect(tx.complete, false);
tx = tx.sign(inputN: i, key: privkey, hashType: SigHashType.single());
}

expect(tx.complete, true);
tx = tx.addOutput(exampleOutput);
expect(tx.complete, false);
// Added output for second input which is therefore invalidated
expect((tx.inputs[0] as P2PKHInput).insig, isNotNull);
expect((tx.inputs[1] as P2PKHInput).insig, isNull);

});

test("replaceInput", () {

// Create tx with 4 legacy (the 2nd to be replaced), 3 witness and 3
// taproot inputs to test invalidation when an input is replaced

final value = BigInt.from(1000000);
final taprootPrevOuts = [
...List.filled(
4,
Output.fromProgram(value, P2PKH.fromPublicKey(keyVec.publicObj)),
),
...List.filled(
3,
Output.fromProgram(value, P2WPKH.fromPublicKey(keyVec.publicObj)),
),
...List.filled(
3,
Output.fromProgram(value, P2TR.fromTweakedKey(keyVec.publicObj)),
),
];

final tx = Transaction(
inputs: [
// Legacy inputs
...List.generate(
4,
(i) => P2PKHInput(prevOut: examplePrevOut, publicKey: keyVec.publicObj),
),
// Witness inputs
...List.generate(
3,
(i) => P2WPKHInput(prevOut: examplePrevOut, publicKey: keyVec.publicObj),
),
// Taproot inputs
...List.generate(
3,
(i) => TaprootKeyInput(prevOut: examplePrevOut),
),
],
outputs: [exampleOutput],
)
// Sign legacy
.sign(inputN: 0, key: keyVec.privateObj)
.sign(
inputN: 2,
key: keyVec.privateObj,
hashType: SigHashType.all(anyOneCanPay: true),
)
.sign(
inputN: 3,
key: keyVec.privateObj,
hashType: SigHashType.single(),
)
// Sign witness
.sign(inputN: 4, key: keyVec.privateObj, value: value)
.sign(
inputN: 5,
key: keyVec.privateObj,
hashType: SigHashType.all(anyOneCanPay: true),
value: value,
)
.sign(
inputN: 6,
key: keyVec.privateObj,
hashType: SigHashType.none(),
value: value,
)
// Sign taproot
.sign(inputN: 7, key: keyVec.privateObj, prevOuts: taprootPrevOuts)
.sign(
inputN: 8,
key: keyVec.privateObj,
hashType: SigHashType.all(anyOneCanPay: true),
prevOuts: taprootPrevOuts,
)
.sign(
inputN: 9,
key: keyVec.privateObj,
hashType: SigHashType.none(),
prevOuts: taprootPrevOuts,
);

void expectComplete(Transaction tx, Iterable<bool> completes)
=> expect(tx.inputs.map((i) => i.complete), completes);

// All but the 2nd input is complete
expectComplete(tx, Iterable.generate(10, (i) => i != 1));

// Do not invalidate anything when prevout and sequence is the same
expectComplete(
tx.replaceInput(
RawInput(
prevOut: examplePrevOut,
scriptSig: hexToBytes("00"),
),
1,
),
Iterable.generate(10, (i) => true),
);

// Only invalidate SIGHASH_ALL or taproot inputs without ANYONECANPAY when
// sequence changes
expectComplete(
tx.replaceInput(
RawInput(
prevOut: examplePrevOut,
scriptSig: hexToBytes("00"),
sequence: 0,
),
1,
),
[
// Legacy
false, true, true, true,
// Witness
false, true, true,
// Taproot
false, true, false,
],
);


// Only keep ANYONECANPAY when prevout changes
expectComplete(
tx.replaceInput(
RawInput(
prevOut: OutPoint(examplePrevOut.hash, 1),
scriptSig: hexToBytes("00"),
),
1,
),
[
// Legacy
false, true, true, false,
// Witness
false, true, false,
// Taproot
false, true, false,
],
);

// Sign second input outside tx and check it is OK
final signedIn = (tx.inputs[1] as P2PKHInput).sign(
tx: tx,
inputN: 1,
key: keyVec.privateObj,
);
final signedTx = tx.replaceInput(signedIn, 1);

expectComplete(signedTx, Iterable.generate(10, (i) => true));

// Added output for second input which is therefore invalidated
expect((tx.inputs[0] as P2PKHInput).insig, isNotNull);
expect((tx.inputs[1] as P2PKHInput).insig, isNull);
expect(
signedTx.toHex(),
"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",
);

});

});

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