Abstract: Method for registering and updating an electronically stored and versioned alpha digital document (A) in a digital document register by storing, for each version, not the document but a public ownership key; a digital document hash value; and a digital document signature. The invention is characterised by the steps a) providing a first document version, defined in a document description language to have a defined rendered graphic representation; b) registering said first version; c) providing a second document version by adding a reversibly added part to said first document version, said second version comprising a second set of metadata; and d) registering said second version, in that said second metadata is embedded in the second version without affecting said graphic representation, in that at least a part of the reversibly added part can be unambiguously generated based on the second metadata, and in that the registering in step d comprises storing a hash of the second metadata.