code: function __encode(raw, key) {
  
    var len = _.size(key);
    var cc = len; // key switch counter
    return new Buffer(_.map(raw, function(num, index) {
  
      if (cc-- > 0) {
        return (num + key.shift()) % 256;
      }
      return (num + raw[index - len]) % 256;
    }));
  }
docs: body cipher encode
  
  @function __encode
  @param {Buffer} raw - data
  @param {Array} key - user key
  @return {Buffer}