quantumexplorer / groestl-hash-js Goto Github PK

During a review of our dependencies, we noticed this snippet here: https://github.com/QuantumExplorer/groestl-hash-js/blob/master/lib/groestl.js#L1079

var B64 = function(n, x) {
  if (n === 7) {
    return x.lo & 0xFF;
  }
  var bits = (7 - n) * 8;
  if (bits >= 32) { //faster than >= 32
    return (x.hi >>> (bits - 32)) & 0xFF;
  }
  else {
    var bitsOff32 = 32 - bits,
      toMoveDown = this.hi << bitsOff32 >>> bitsOff32;
    return (x.lo >>> bits | (toMoveDown << bitsOff32)) & 0xFF;
  }
}

On line 1079 there is reference to this.hi. In this context, this refers to the object that this function belongs to, but I don't think hi is ever defined there. So the value of this.hi is always undefined.

This means that toMoveDown = this.hi << bitsOff32 >>> bitsOff32; will always be 0.

Is this intended or a bug?

This is not groestl 256(as show in docs)... it's 512, you can't just cut half of 512 bit hash and get 256 hash....