ethers.js/src.browser/random-bytes.ts
2018-06-15 04:18:17 -04:00

42 lines
1.2 KiB
TypeScript

'use strict';
import { arrayify } from '../src.ts/utils/convert';
import { defineReadOnly } from '../src.ts/utils/properties';
let crypto: any = global['crypto'] || global['msCrypto'];
if (!crypto || !crypto.getRandomValues) {
console.log('WARNING: Missing strong random number source; using weak randomBytes');
crypto = {
getRandomValues: function(buffer: Uint8Array) {
for (var round = 0; round < 20; round++) {
for (var i = 0; i < buffer.length; i++) {
if (round) {
buffer[i] ^= Math.trunc(256 * Math.random());
} else {
buffer[i] = Math.trunc(256 * Math.random());
}
}
}
return buffer;
},
_weakCrypto: true
};
}
export function randomBytes(length) {
if (length <= 0 || length > 1024 || parseInt(length) != length) {
throw new Error('invalid length');
}
var result = new Uint8Array(length);
crypto.getRandomValues(result);
return arrayify(result);
};
if (crypto._weakCrypto === true) {
defineReadOnly(randomBytes, '_weakCrypto', true);
}