| 1 | import { _0n, BN, bnToU8a, hasBigInt, isU8a, nToU8a, u8aToBigInt } from '@polkadot/util';
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| 2 | import { BigInt } from '@polkadot/x-bigint';
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| 3 | import { BN_BE_256_OPTS, BN_BE_OPTS } from '../bn.js';
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| 4 | const N = 'ffffffff ffffffff ffffffff fffffffe baaedce6 af48a03b bfd25e8c d0364141'.replace(/ /g, '');
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| 5 | const N_BI = BigInt(`0x${N}`);
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| 6 | const N_BN = new BN(N, 'hex');
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| 7 | function addBi(seckey, tweak) {
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| 8 | let res = u8aToBigInt(tweak, BN_BE_OPTS);
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| 9 | if (res >= N_BI) {
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| 10 | throw new Error('Tweak parameter is out of range');
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| 11 | }
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| 12 | res += u8aToBigInt(seckey, BN_BE_OPTS);
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| 13 | if (res >= N_BI) {
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| 14 | res -= N_BI;
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| 15 | }
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| 16 | if (res === _0n) {
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| 17 | throw new Error('Invalid resulting private key');
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| 18 | }
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| 19 | return nToU8a(res, BN_BE_256_OPTS);
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| 20 | }
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| 21 | function addBn(seckey, tweak) {
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| 22 | const res = new BN(tweak);
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| 23 | if (res.cmp(N_BN) >= 0) {
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| 24 | throw new Error('Tweak parameter is out of range');
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| 25 | }
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| 26 | res.iadd(new BN(seckey));
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| 27 | if (res.cmp(N_BN) >= 0) {
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| 28 | res.isub(N_BN);
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| 29 | }
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| 30 | if (res.isZero()) {
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| 31 | throw new Error('Invalid resulting private key');
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| 32 | }
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| 33 | return bnToU8a(res, BN_BE_256_OPTS);
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| 34 | }
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| 35 | export function secp256k1PrivateKeyTweakAdd(seckey, tweak, onlyBn) {
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| 36 | if (!isU8a(seckey) || seckey.length !== 32) {
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| 37 | throw new Error('Expected seckey to be an Uint8Array with length 32');
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| 38 | }
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| 39 | else if (!isU8a(tweak) || tweak.length !== 32) {
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| 40 | throw new Error('Expected tweak to be an Uint8Array with length 32');
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| 41 | }
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| 42 | return !hasBigInt || onlyBn
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| 43 | ? addBn(seckey, tweak)
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| 44 | : addBi(seckey, tweak);
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| 45 | }
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