US Patent 11233657 Method and system for registering digital documents

Method for registering an electronically stored digital document (A), comprising the steps of a) providing to an owning party a digital document and a private ownership key, which private ownership key is a private key in an asymmetric cryptographic key pair also comprising a corresponding public ownership key; b) calculating a digital document hash value based upon the document (A); c) the owning party using the private ownership key to calculate a digital document signature of the document (A); d) digitally storing in an electronic digital document register not the document (A), but the document signature as well as the public ownership key and the document hash value. The invention also relates to a system.