JS client for evaluating proof-of-work cost

client-poc.js

var argv = require('minimist')(process.argv.slice(2));
var cjs = require('cryptojs');
var s = require('sprintf-js');
var sha1 = cjs.Crypto.SHA1;


var repeatString = function(s, n) {
  var ret = '';
  for (i = 0; i < n; i++) {
    ret += s;
  }
  return ret;
}

var proof = function(challenge, bits) {
  var zeros = Math.ceil(bits/4.0),
    counter = 0,
    paddedZeros = repeatString("0", zeros);

  while (true) {
    var digest = sha1(challenge+(counter).toString(16));
    if (digest.slice(0, zeros) == paddedZeros) {
      return {
        counter: counter,
        digest: digest
      };
    }
    counter++;
  }
};

var bench = function(fn, args) {
   var start = new Date().getTime();
   var result = fn.apply(undefined, args);
   var end = new Date().getTime();
   return {
     time: end - start,
     result: result
   };
};

var iter = 0;
var toBits = parseInt(argv.bits);
var toIter = parseInt(argv.iterations);
console.log("# going to", toBits, "bits", toIter, "times each");
console.log("iteratation,time,num_bits,counter")

for (currentBits = 2; currentBits <= toBits; currentBits++) {
  for (j = 0; j < toIter; j++) {
    var challenge = Math.random().toString(36).replace(/[^a-z]+/g, '').substr(0, 10);
    var ret = bench(proof, [challenge, currentBits]);
    console.log(s.sprintf("%d,%f,%d,%d", iter, ret.time, currentBits, ret.result.counter));
    iter++;
  }
}