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feat: add tweakHash and extraEntropy optional params to signSchnorr() #6

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feat: add tweakHash and extraEntropy optional params to signSchnorr() #6

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9100c1d
feat: add `tweakHash` and `extraEntropy` optional params to` signSchn…
motorina0 Jan 29, 2022
8ef66c0
feat: add tweak for verifySchnorr()
motorina0 Jan 31, 2022
cb4cf46
chore: fix typo
motorina0 Feb 3, 2022
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6 changes: 3 additions & 3 deletions package-lock.json
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2 changes: 1 addition & 1 deletion package.json
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Original file line number Diff line number Diff line change
Expand Up @@ -71,7 +71,7 @@
"prettier": "^2.4.1",
"proxyquire": "^2.0.1",
"rimraf": "^2.6.3",
"tiny-secp256k1": "^2.1.2",
"tiny-secp256k1": "^2.2.0",
"ts-node": "^8.3.0",
"tslint": "^6.1.3",
"typescript": "^4.4.4"
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9 changes: 6 additions & 3 deletions src/ecpair.d.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -26,8 +26,8 @@ export interface ECPairInterface extends Signer {
privateKey?: Buffer;
toWIF(): string;
verify(hash: Buffer, signature: Buffer): boolean;
verifySchnorr(hash: Buffer, signature: Buffer): boolean;
signSchnorr(hash: Buffer): Buffer;
verifySchnorr(hash: Buffer, signature: Buffer, tweak?: Buffer): boolean;
signSchnorr(hash: Buffer, extraEntropy?: Buffer, tweak?: Buffer): Buffer;
}
export interface ECPairAPI {
isPoint(maybePoint: any): boolean;
Expand All @@ -39,8 +39,11 @@ export interface ECPairAPI {
export interface TinySecp256k1Interface {
isPoint(p: Uint8Array): boolean;
pointCompress(p: Uint8Array, compressed?: boolean): Uint8Array;
isPrivate(d: Uint8Array): boolean;
pointFromScalar(d: Uint8Array, compressed?: boolean): Uint8Array | null;
pointAddScalar(p: Uint8Array, tweak: Uint8Array, compressed?: boolean): Uint8Array | null;
isPrivate(d: Uint8Array): boolean;
privateAdd(d: Uint8Array, tweak: Uint8Array): Uint8Array | null;
privateNegate(d: Uint8Array): Uint8Array;
sign(h: Uint8Array, d: Uint8Array, e?: Uint8Array): Uint8Array;
signSchnorr?(h: Uint8Array, d: Uint8Array, e?: Uint8Array): Uint8Array;
verify(h: Uint8Array, Q: Uint8Array, signature: Uint8Array, strict?: boolean): boolean;
Expand Down
31 changes: 27 additions & 4 deletions src/ecpair.js
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Original file line number Diff line number Diff line change
Expand Up @@ -116,19 +116,42 @@ function ECPairFactory(ecc) {
return Buffer.from(sig);
}
}
signSchnorr(hash) {
signSchnorr(hash, e, tweak) {
if (!this.privateKey) throw new Error('Missing private key');
if (!ecc.signSchnorr)
throw new Error('signSchnorr not supported by ecc library');
return Buffer.from(ecc.signSchnorr(hash, this.privateKey));
if (!tweak) return Buffer.from(ecc.signSchnorr(hash, this.privateKey, e));
const privateKey =
this.publicKey[0] === 2
? this.privateKey
: ecc.privateNegate(this.privateKey);
const tweakedPrivateKey = ecc.privateAdd(privateKey, tweak);
if (!tweakedPrivateKey) {
throw new Error('Invalid tweaked private key!');
}
return Buffer.from(ecc.signSchnorr(hash, tweakedPrivateKey, e));
}
verify(hash, signature) {
return ecc.verify(hash, this.publicKey, signature);
}
verifySchnorr(hash, signature) {
verifySchnorr(hash, signature, tweak) {
if (!ecc.verifySchnorr)
throw new Error('verifySchnorr not supported by ecc library');
return ecc.verifySchnorr(hash, this.publicKey.subarray(1, 33), signature);
if (!tweak)
return ecc.verifySchnorr(
hash,
this.publicKey.subarray(1, 33),
signature,
);
const tweakedPublicKey = ecc.pointAddScalar(this.publicKey, tweak);
if (!tweakedPublicKey) {
throw new Error('Invalid tweaked publc key!');
}
return ecc.verifySchnorr(
hash,
tweakedPublicKey.subarray(1, 33),
signature,
);
}
}
return {
Expand Down
75 changes: 75 additions & 0 deletions src/testecc.js
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Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,61 @@ function testEcc(ecc) {
h('fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364142'),
),
);
// 1 + 0 == 1
assert(
Buffer.from(
ecc.privateAdd(
h('0000000000000000000000000000000000000000000000000000000000000001'),
h('0000000000000000000000000000000000000000000000000000000000000000'),
),
).equals(
h('0000000000000000000000000000000000000000000000000000000000000001'),
),
);
// -3 + 3 == 0
assert(
ecc.privateAdd(
h('fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd036413e'),
h('0000000000000000000000000000000000000000000000000000000000000003'),
) === null,
);
assert(
Buffer.from(
ecc.privateAdd(
h('e211078564db65c3ce7704f08262b1f38f1ef412ad15b5ac2d76657a63b2c500'),
h('b51fbb69051255d1becbd683de5848242a89c229348dd72896a87ada94ae8665'),
),
).equals(
h('9730c2ee69edbb958d42db7460bafa18fef9d955325aec99044c81c8282b0a24'),
),
);
assert(
Buffer.from(
ecc.privateNegate(
h('0000000000000000000000000000000000000000000000000000000000000001'),
),
).equals(
h('fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364140'),
),
);
assert(
Buffer.from(
ecc.privateNegate(
h('fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd036413e'),
),
).equals(
h('0000000000000000000000000000000000000000000000000000000000000003'),
),
);
assert(
Buffer.from(
ecc.privateNegate(
h('b1121e4088a66a28f5b6b0f5844943ecd9f610196d7bb83b25214b60452c09af'),
),
).equals(
h('4eede1bf775995d70a494f0a7bb6bc11e0b8cccd41cce8009ab1132c8b0a3792'),
),
);
assert(
Buffer.from(
ecc.pointCompress(
Expand Down Expand Up @@ -90,6 +145,26 @@ function testEcc(ecc) {
),
),
);
assert(
Buffer.from(
ecc.pointAddScalar(
h('0379be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798'),
h('0000000000000000000000000000000000000000000000000000000000000002'),
),
).equals(
h('0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798'),
),
);
assert(
Buffer.from(
ecc.pointAddScalar(
h('0379be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798'),
h('fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364140'),
),
).equals(
h('03c6047f9441ed7d6d3045406e95c07cd85c778e4b8cef3ca7abac09b95c709ee5'),
),
);
assert(
Buffer.from(
ecc.pointFromScalar(
Expand Down
37 changes: 37 additions & 0 deletions test/ecpair.spec.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -315,6 +315,26 @@ describe('ECPair', () => {
);
});

it('creates signature for tweaked private key', () => {
const kP = ECPair.fromPrivateKey(ONE, {
compressed: true,
});
const h = Buffer.alloc(32, 2);
const tweak = Buffer.from(
'3cf5216d476a5e637bf0da674e50ddf55c403270dd36494dfcca438132fa30e7',
'hex',
);
const schnorrTweakedSig = Buffer.from(
'c2cc6ba5ac926ae7a99b2dc4d410532c05787c562e5ae02fb4f204e8a4e86384ef4b436597bbc1808dcfa9f3e4223e0c2a9ab6fd4b43ab2c6d18405c43b8f0a6',
'hex',
);

assert.deepStrictEqual(
kP.signSchnorr(h, undefined, tweak).toString('hex'),
schnorrTweakedSig.toString('hex'),
);
});

it(
'wraps tinysecp.signSchnorr',
hoodwink(function (this: any): void {
Expand Down Expand Up @@ -386,6 +406,23 @@ describe('ECPair', () => {
assert.strictEqual(kP.verifySchnorr(h, schnorrsig), true);
});

it('checks signature for tweaked pubic key', () => {
const kP = ECPair.fromPrivateKey(ONE, {
compressed: false,
});
const h = Buffer.alloc(32, 2);
const tweak = Buffer.from(
'3cf5216d476a5e637bf0da674e50ddf55c403270dd36494dfcca438132fa30e7',
'hex',
);
const schnorrsig = Buffer.from(
'c2cc6ba5ac926ae7a99b2dc4d410532c05787c562e5ae02fb4f204e8a4e86384ef4b436597bbc1808dcfa9f3e4223e0c2a9ab6fd4b43ab2c6d18405c43b8f0a6',
'hex',
);

assert.strictEqual(kP.verifySchnorr(h, schnorrsig, tweak), true);
});

it(
'wraps tinysecp.verifySchnorr',
hoodwink(function (this: any): void {
Expand Down
47 changes: 40 additions & 7 deletions ts_src/ecpair.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -40,8 +40,8 @@ export interface ECPairInterface extends Signer {
privateKey?: Buffer;
toWIF(): string;
verify(hash: Buffer, signature: Buffer): boolean;
verifySchnorr(hash: Buffer, signature: Buffer): boolean;
signSchnorr(hash: Buffer): Buffer;
verifySchnorr(hash: Buffer, signature: Buffer, tweak?: Buffer): boolean;
signSchnorr(hash: Buffer, extraEntropy?: Buffer, tweak?: Buffer): Buffer;
}

export interface ECPairAPI {
Expand All @@ -55,8 +55,16 @@ export interface ECPairAPI {
export interface TinySecp256k1Interface {
isPoint(p: Uint8Array): boolean;
pointCompress(p: Uint8Array, compressed?: boolean): Uint8Array;
isPrivate(d: Uint8Array): boolean;
pointFromScalar(d: Uint8Array, compressed?: boolean): Uint8Array | null;
pointAddScalar(
p: Uint8Array,
tweak: Uint8Array,
compressed?: boolean,
): Uint8Array | null;

isPrivate(d: Uint8Array): boolean;
privateAdd(d: Uint8Array, tweak: Uint8Array): Uint8Array | null;
privateNegate(d: Uint8Array): Uint8Array;

sign(h: Uint8Array, d: Uint8Array, e?: Uint8Array): Uint8Array;
signSchnorr?(h: Uint8Array, d: Uint8Array, e?: Uint8Array): Uint8Array;
Expand Down Expand Up @@ -204,21 +212,46 @@ export function ECPairFactory(ecc: TinySecp256k1Interface): ECPairAPI {
}
}

signSchnorr(hash: Buffer): Buffer {
signSchnorr(hash: Buffer, e?: Buffer, tweak?: Buffer): Buffer {
if (!this.privateKey) throw new Error('Missing private key');
if (!ecc.signSchnorr)
throw new Error('signSchnorr not supported by ecc library');
return Buffer.from(ecc.signSchnorr(hash, this.privateKey));
if (!tweak) return Buffer.from(ecc.signSchnorr(hash, this.privateKey, e));

const privateKey =
this.publicKey[0] === 2
? this.privateKey
: ecc.privateNegate(this.privateKey!);

const tweakedPrivateKey = ecc.privateAdd(privateKey, tweak);
if (!tweakedPrivateKey) {
throw new Error('Invalid tweaked private key!');
}
return Buffer.from(ecc.signSchnorr(hash, tweakedPrivateKey, e));
}

verify(hash: Buffer, signature: Buffer): boolean {
return ecc.verify(hash, this.publicKey, signature);
}

verifySchnorr(hash: Buffer, signature: Buffer): boolean {
verifySchnorr(hash: Buffer, signature: Buffer, tweak?: Buffer): boolean {
if (!ecc.verifySchnorr)
throw new Error('verifySchnorr not supported by ecc library');
return ecc.verifySchnorr(hash, this.publicKey.subarray(1, 33), signature);
if (!tweak)
return ecc.verifySchnorr(
hash,
this.publicKey.subarray(1, 33),
signature,
);
const tweakedPublicKey = ecc.pointAddScalar(this.publicKey, tweak);
if (!tweakedPublicKey) {
throw new Error('Invalid tweaked publc key!');
}
return ecc.verifySchnorr(
hash,
tweakedPublicKey.subarray(1, 33),
signature,
);
}
}

Expand Down
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