code: function genKey(bytes, callback) {
    // bytes is optional
    if (arguments.length < 2) {
      callback = bytes;
      bytes = 32;
    }
    if (typeof callback !== 'function') {
      throw("Callback required");
    }
    crypto.randomBytes(bytes, function(err, buf) {
      if (err) return callback (err);
      return callback(null, buf);
    });
  }
docs: /*
  Generate a random key
  
  params:
  bytes (int)      length of key (default=32)
  callback (func)  function to call with err,key
  
  returns: nothing, but runs callback with a Buffer