code: func (e *encryption) Decrypt(data []byte) ([]byte, error) {
  	length := len(data)
  	if e.padding > 0 && length != e.padding {
  		return nil, fmt.Errorf("Data length different than padding, data length %v padding %v", length, e.padding)
  	}
  	out := make([]byte, length)
  	e.transform(data, out)
  	return out, nil
  }
docs: // Decrypt decrypts the data, if padding was used caller must know original length and truncate