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-rw-r--r--package.json2
-rw-r--r--src/ts/0x.js.ts15
-rw-r--r--test/0x.js.ts13
3 files changed, 30 insertions, 0 deletions
diff --git a/package.json b/package.json
index 275a57a93..f88442f37 100644
--- a/package.json
+++ b/package.json
@@ -36,6 +36,7 @@
"@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",
@@ -53,6 +54,7 @@
"dependencies": {
"bignumber.js": "^4.0.2",
"ethereumjs-util": "^5.1.1",
+ "lodash": "^4.17.4",
"web3": "^0.19.0"
}
}
diff --git a/src/ts/0x.js.ts b/src/ts/0x.js.ts
index acbdd01e2..4b9680a18 100644
--- a/src/ts/0x.js.ts
+++ b/src/ts/0x.js.ts
@@ -11,6 +11,8 @@ 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
@@ -34,4 +36,17 @@ 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 71126c7da..e4e3cc0a7 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', () => {
@@ -73,4 +74,16 @@ 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;
+ });
+ });
});