diff options
| -rw-r--r-- | package.json | 2 | ||||
| -rw-r--r-- | src/ts/0x.js.ts | 15 | ||||
| -rw-r--r-- | test/0x.js.ts | 13 |
3 files changed, 30 insertions, 0 deletions
diff --git a/package.json b/package.json index f6740b268..950ad0d38 100644 --- a/package.json +++ b/package.json @@ -37,6 +37,7 @@ "@types/mocha": "^2.2.41", "@types/node": "^7.0.22", "awesome-typescript-loader": "^3.1.3", + "bignumber.js": "^4.0.2", "chai": "^3.5.0", "mocha": "^3.4.1", "npm-run-all": "^4.0.2", @@ -55,6 +56,7 @@ "bignumber.js": "^4.0.2", "ethereumjs-util": "^5.1.1", "jsonschema": "^1.1.1", + "lodash": "^4.17.4", "web3": "^0.19.0" } } diff --git a/src/ts/0x.js.ts b/src/ts/0x.js.ts index 8de87e96e..1cc2d8b44 100644 --- a/src/ts/0x.js.ts +++ b/src/ts/0x.js.ts @@ -12,6 +12,8 @@ export interface ECSignature { s: string; } +const MAX_DIGITS_IN_UNSIGNED_256_INT = 78; + export class ZeroEx { /** * Verifies that the elliptic curve signature `signature` was generated @@ -35,4 +37,17 @@ export class ZeroEx { return false; } } + /** + * Generates pseudo-random 256 bit salt. + * The salt is used to ensure that the 0x order generated has a unique orderHash that does + * not collide with any other outstanding orders. + */ + public static generatePseudoRandomSalt(): BigNumber.BigNumber { + // BigNumber.random returns a pseudo-random number between 0 & 1 with a passed in number of decimal places. + // Source: https://mikemcl.github.io/bignumber.js/#random + const randomNumber = BigNumber.random(MAX_DIGITS_IN_UNSIGNED_256_INT); + const factor = new BigNumber(10).pow(MAX_DIGITS_IN_UNSIGNED_256_INT - 1); + const salt = randomNumber.times(factor).round(); + return salt; + } } diff --git a/test/0x.js.ts b/test/0x.js.ts index 4d0b03a2a..2c4471e0f 100644 --- a/test/0x.js.ts +++ b/test/0x.js.ts @@ -1,6 +1,7 @@ import {ZeroEx} from '../src/ts/0x.js'; import {expect} from 'chai'; import 'mocha'; +import * as BigNumber from 'bignumber.js'; describe('ZeroEx library', () => { describe('#isValidSignature', () => { @@ -89,4 +90,16 @@ describe('ZeroEx library', () => { expect(isValid).to.be.true; }); }); + describe('#generateSalt', () => { + it('generates different salts', () => { + const equal = ZeroEx.generatePseudoRandomSalt().eq(ZeroEx.generatePseudoRandomSalt()); + expect(equal).to.be.false; + }); + it('generates salt in range [0..2^256)', () => { + const salt = ZeroEx.generatePseudoRandomSalt(); + expect(salt.greaterThanOrEqualTo(0)).to.be.true; + const twoPow256 = new BigNumber(2).pow(256); + expect(salt.lessThan(twoPow256)).to.be.true; + }); + }); }); |