@steemit/steem-js/lib/auth/ecc/src/key_utils.js

JavaScript library for the Steem blockchain

"use strict";

const PrivateKey = require('./key_private');
const hash = require('./hash');
const secureRandom = require('secure-random');

// hash for .25 second
const HASH_POWER_MILLS = 250;
let entropyPos = 0,
  entropyCount = 0;
const entropyArray = secureRandom.randomBuffer(101);
module.exports = {
  addEntropy(...ints) {
    entropyCount++;
    for (const i of ints) {
      const pos = entropyPos++ % 101;
      const i2 = entropyArray[pos] += i;
      if (i2 > 9007199254740991) entropyArray[pos] = 0;
    }
  },
  /**
      A week random number generator can run out of entropy.  This should ensure even the worst random number implementation will be reasonably safe.
       @param1 string entropy of at least 32 bytes
  */
  random32ByteBuffer(entropy = this.browserEntropy()) {
    if (!(typeof entropy === 'string')) {
      throw new Error("string required for entropy");
    }
    if (entropy.length < 32) {
      throw new Error("expecting at least 32 bytes of entropy");
    }
    const start_t = Date.now();
    while (Date.now() - start_t < HASH_POWER_MILLS) entropy = hash.sha256(entropy);
    const hash_array = [];
    hash_array.push(entropy);

    // Hashing for 1 second may helps the computer is not low on entropy (this method may be called back-to-back).
    hash_array.push(secureRandom.randomBuffer(32));
    return hash.sha256(Buffer.concat(hash_array));
  },
  get_random_key(entropy) {
    return PrivateKey.fromBuffer(this.random32ByteBuffer(entropy));
  },
  // Turn invisible space like characters into a single space
  // normalize_brain_key(brain_key){
  //     if (!(typeof brain_key === 'string')) {
  //         throw new Error("string required for brain_key");
  //     }
  //     brain_key = brain_key.trim();
  //     return brain_key.split(/[\t\n\v\f\r ]+/).join(' ');
  // },

  browserEntropy() {
    let entropyStr = Array(entropyArray).join();
    try {
      entropyStr += new Date().toString() + " " + window.screen.height + " " + window.screen.width + " " + window.screen.colorDepth + " " + " " + window.screen.availHeight + " " + window.screen.availWidth + " " + window.screen.pixelDepth + navigator.language + " " + window.location + " " + window.history.length;
      for (let i = 0, mimeType; i < navigator.mimeTypes.length; i++) {
        mimeType = navigator.mimeTypes[i];
        entropyStr += mimeType.description + " " + mimeType.type + " " + mimeType.suffixes + " ";
      }
      console.log("INFO\tbrowserEntropy gathered", entropyCount, 'events');
    } catch (error) {
      //nodejs:ReferenceError: window is not defined
      entropyStr += hash.sha256(new Date().toString());
    }
    const b = new Buffer(entropyStr);
    entropyStr += b.toString('binary') + " " + new Date().toString();
    return entropyStr;
  }
};