It’s not just the traces of data that we leave in the online world. We leave digital products (goods) by active action like login ID, game items, pictures, videos, blog posting, and comments. These also can have value as property by transferring data sovereignty to users. These digital products and data all are embraced to be called digital assets. In contrast to real like physical world assets like real estate, house, jewelry, and money, it means the asset in the digital world. But for the digital assets to act like the assets of reality, it must overcome the limitation of digital. That is, it must be impossible to replicate so that the exclusiveness can be guaranteed and, trading must be possible. And the proof of ownership must be possible, and ownership must be transferred when trading. To secure data sovereignty, data storage and control should not be subordinate to service and users should be able to control.