Linking documents through digital watermarking
AssigneeDigimarc Corporation
InventorJonathan L. Hawes
Life of this patent
Estimating the term…
Abstract
The present invention relates to linking documents through digital watermarking. In one implementation, an identification document is embedded with a first digital watermark. The first digital watermark includes a first identifier. Before issuing a second document, like a boarding pass or ticket, the first identifier is extracted from the identification document. The first identifier is manipulated or altered to produce a second identifier. The second identifier, however, remains related to the first identifier. The second document is embedded with a second digital watermark including the second identifier. Thus, the identification document and the second document are linked through the first and second watermark identifiers.
Claims12
A method of linking a first document to at least a second document, the first document comprising a first digital watermark including a first identifier, said method comprising:
- decoding the first digital watermark to obtain the first identifier;
- providing a second identifier, wherein the second identifier is related to the first identifier;
- and
- embedding in the second document a second digital watermark including the second identifier.
A method of providing security for an printed document, said method comprising the steps of:
- linking an identification document to the printed document, said linking comprising:
- obtaining a first identifier from machine-readable indicia carried by the identification document;
- providing a second identifier, the second identifier being related to the first identifier;
- and
- printing the printed document, the printed document including the second identifier in the form of machine-readable indicia;
- and
- determining whether the identification document and the printed document are linked by verifying that the first identifier and the second identifier are related.
Dependencies are inferred from the claim text.