Linking documents through digital watermarking

• US 20030150922A1
• Filed: 06/14/2002
• Published: 08/14/2003
• Est. Priority Date: 02/12/2002
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Hawes, Jonathan L.
• Granted Patent: US 6,869,023 B2
• Time in Patent Office: Days
• US Class Current: 235/494
• CPC Class Codes: B42D 25/00 Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof printing processes to produce identification or security features B41M3/14
• CPC Class Codes: B42D 25/23 Identity cards
• CPC Class Codes: B42D 25/333 Watermarks
• CPC Class Codes: G06F 16/955 using information identifiers, e.g. uniform resource locators [URL]
• CPC Class Codes: G06F 3/005 Input arrangements through a video camera
• CPC Class Codes: G06K 19/06 characterised by the kind of the digital marking, e.g. shape, nature, code
• CPC Class Codes: G06K 19/06037 multi-dimensional coding
• CPC Class Codes: G06K 19/06046 Constructional details
• CPC Class Codes: G06K 19/14 the marking being sensed by radiation
• CPC Class Codes: G06K 19/18 Constructional details
• CPC Class Codes: G06K 2019/06253 for a specific application
• CPC Class Codes: G06K 7/1417 2D bar codes
• CPC Class Codes: G06K 7/1447 extracting optical codes from image or text carrying said optical code
• CPC Class Codes: G06Q 20/341 Active cards, i.e. cards including their own processing means, e.g. including an IC or chip
• CPC Class Codes: G06Q 20/40145 Biometric identity checks
• CPC Class Codes: G06Q 30/02 Marketing; Price estimation or determination; Fundraising
• CPC Class Codes: G06T 1/0021 Image watermarking
• CPC Class Codes: G07C 2209/41 with means for the generation of identity documents
• CPC Class Codes: G07C 9/253 visually
• CPC Class Codes: G07C 9/257 electronically G07C9/26 takes precedence
• CPC Class Codes: G07D 7/0034 : using watermarks
• CPC Class Codes: G07D 7/004 : using digital security elements, e.g. information coded on a magnetic thread or strip
• CPC Class Codes: G07F 17/16 : for devices exhibiting advertisements, announcements, pictures or the like
• CPC Class Codes: G07F 17/26 : for printing, stamping, franking, typing or teleprinting apparatus ticket printing or the like apparatus G07F17/42
• CPC Class Codes: G07F 7/08 : by coded identity card or credit card or other personal identification means without personal verification means G07F7/02
• CPC Class Codes: G07F 7/086 : by passive credit-cards adapted therefor, e.g. constructive particularities to avoid counterfeiting, e.g. by inclusion of a physical or chemical security-layer for security documents G07D7/00; for the reading of record-carriers in general G06K7/00; for the design of coded credit-cards G06K19/10
• CPC Class Codes: G07F 7/1008 : Active credit-cards provided with means to personalise their use, e.g. with PIN-introduction/comparison system
• CPC Class Codes: G07F 7/12 : Card verification
• CPC Class Codes: G10L 19/018 : Audio watermarking, i.e. embedding inaudible data in the audio signal
• CPC Class Codes: G11B 20/00086 : Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00884 : involving a watermark, i.e. a barely perceptible transformation of the original data which can nevertheless be recognised by an algorithm
• CPC Class Codes: G11B 20/00891 : embedded in audio data
• CPC Class Codes: H04N 1/32122 : in a separate device, e.g. in a memory or on a display separate from image data
• CPC Class Codes: H04N 1/32144 : embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
• CPC Class Codes: H04N 1/3216 : using Fourier transforms
• CPC Class Codes: H04N 1/32203 : Spatial or amplitude domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32208 : involving changing the magnitude of selected pixels, e.g. overlay of information or super-imposition H04N1/32219, H04N1/32224 take precedence
• CPC Class Codes: H04N 1/32251 : in multilevel data, e.g. greyscale or continuous tone data
• CPC Class Codes: H04N 1/32288 : Multiple embedding, e.g. cocktail embedding, or redundant embedding, e.g. repeating the additional information at a plurality of locations in the image
• CPC Class Codes: H04N 1/32352 : Controlling detectability or arrangements to facilitate detection or retrieval of the embedded information, e.g. using markers for decoding, detection or retrieval operations H04N1/32149 and subgroups take precedence
• CPC Class Codes: H04N 2201/3225 : of data relating to an image, a page or a document
• CPC Class Codes: H04N 2201/3226 : of identification information or the like, e.g. ID code, index, title, part of an image, reduced-size image
• CPC Class Codes: H04N 2201/3233 : of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/327 : which are undetectable to the naked eye, e.g. embedded codes
• CPC Class Codes: H04N 2201/3271 : Printing or stamping
• CPC Class Codes: H04N 2201/3274 : Storage or retrieval of prestored additional information

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.

Claims

1. 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.

2. The method of claim 1, wherein the second identifier comprises the first identifier.

3. The method of claim 1, wherein the second identifier comprises a cryptographic permutation of the first identifier.

4. The method of claim 1, wherein the second identifier is randomly or pseudo-randomly generated.

5. The method of claim 1, wherein the second identifier is related to the first identifier through association in a database or data record.

6. An authentication method for the second document produced according to the method of claim 1, the authentication method comprising the steps of:

decoding the first digital watermark from the first document to obtain the first identifier;

decoding the second digital watermark from the second document to obtain the second identifier; and

comparing the first identifier and the second identifier to determine whether the second document is authentic.

7. The method of claim 6, wherein said comparing step comprises determining whether the first identifier and second identifier match.

8. The method of claim 6, wherein said comparing step comprises determining whether the second identifier comprises a cryptographic permutation of the first identifier.

9. An authentication method for the first document produced according to the method of claim 5, the authentication method comprising the steps of:

decoding the first digital watermark from the first document to obtain the first identifier;

decoding the second digital watermark from the second document to obtain the second identifier; and

comparing the first identifier and the second identifier to determine whether the second document is authentic, wherein said comparing step comprises accessing the data record or database to see if the first identifier and the second identifier are associated therein.

12. The method of claim 1, wherein the first identifier includes a first set of information and the second identifier includes a second set of information, wherein the first and second sets of information are related.

10. 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.

11. The method of claim 10, wherein the machine-readable indicia comprises a digital watermark.