Digital watermark embedding and decoding using encryption keys

• US 7,062,069 B2
• Filed: 04/06/2004
• Issued: 06/13/2006
• Est. Priority Date: 05/08/1995
• Status: Expired due to Fees

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Rhoads, Geoffrey B.
• Primary Examiner(s): Couso, Jose L.
• Application Number:
  US10/819,716
• Publication Number:
  US 20040264735A1
• Time in Patent Office: 798 Days
• Field of Search: 382/100, 382/232, 382/284, 235/494, 348/474, 348/475, 358/426.02, 358/426.12, 380/54, 380/200, 380231-234, 380277-285, 380/287, 705/44, 705/51, 705/58, 707/9, 707/101, 713/165, 713/167, 713/176, 713/179
• US Class Current: 382/100
• 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 25/333 Watermarks
• CPC Class Codes: G06F 16/955 using information identifiers, e.g. uniform resource locators [URL]
• 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 20/1235 with control of digital rights management [DRM]
• 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: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 1/0064 Geometric transfor invariant watermarking, e.g. affine transform invariant
• CPC Class Codes: G06T 1/0071 using multiple or alternating watermarks
• CPC Class Codes: G06T 2201/0051 Embedding of the watermark in the spatial domain
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain
• CPC Class Codes: G06T 2201/0061 Embedding of the watermark in each block of the image, e.g. segmented watermarking
• CPC Class Codes: G06T 2201/0064 : for copy protection or copy management, e.g. CGMS, copy only once, one-time copy
• CPC Class Codes: G06T 2201/0065 : Extraction of an embedded watermark; Reliable detection
• CPC Class Codes: G06V 30/40 : Document-oriented image-based pattern recognition
• CPC Class Codes: G07C 9/253 : visually
• 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 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: 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: H04H 20/31 : using in-band signals, e.g. subsonic or cue signal
• CPC Class Codes: H04L 63/06 : for supporting key management in a packet data network cryptographic mechanisms or cryptographic arrangements for key management H04L9/08
• CPC Class Codes: H04N 1/00005 : relating to image data
• CPC Class Codes: H04N 1/00037 : Detecting, i.e. determining the occurrence of a predetermined state H04N1/00031 takes precedence
• CPC Class Codes: H04N 1/00079 : remotely
• 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 1/32149 : Methods relating to embedding, encoding, decoding, detection or retrieval operations
• CPC Class Codes: H04N 1/32154 : Transform domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/3216 : using Fourier transforms
• CPC Class Codes: H04N 1/32187 : with selective or adaptive application of the additional information, e.g. in selected frequency coefficients
• 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 1/32229 : with selective or adaptive application of the additional information, e.g. in selected regions of the image H04N1/32213 takes 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 19/467 : characterised by the embedded information being invisible, e.g. watermarking
• CPC Class Codes: H04N 19/645 : by grouping of coefficients into blocks after the transform
• CPC Class Codes: H04N 21/23892 : involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level
• CPC Class Codes: H04N 21/44008 : involving operations for analysing video streams, e.g. detecting features or characteristics in the video stream arrangements characterised by components specially adapted for monitoring, identification or recognition of video in broadcast systems H04H60/59
• CPC Class Codes: H04N 21/4627 : Rights management associated to the content security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08
• CPC Class Codes: H04N 21/8358 : involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467
• CPC Class Codes: H04N 2201/3205 : of identification information, e.g. name or ID code H04N2201/3209 takes precedence
• CPC Class Codes: H04N 2201/3207 : of an address
• 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 2201/323 : for tracing or tracking, e.g. forensic tracing of unauthorized copies
• 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
• CPC Class Codes: H04N 2201/328 : Processing of the additional information
• CPC Class Codes: H04N 2201/3284 : for error correction
• CPC Class Codes: H04N 7/163 : by receiver means only

Abstract

Digital watermarks are embedded and decoded from host media signals like images and audio using encryption keys. The encryption keys are used to encrypt different components of the digital watermark message. The encryption keys can be used to scramble the digital watermark and components of it in alternative ways, including scrambling the mapping of the message to the host signal and scrambling carrier signals used to encode the message. Spread spectrum, feature based, and quantization based embedding and decoding schemes may be used in various combinations in the watermark encoder and decoder. Portions of the digital watermark may be encrypted to provide private watermark data, while other portions may be un-encrypted to provide public watermark data.

Claims

1. A method of embedding a digital watermark in a host media signal, the method comprising:

receiving a message comprising variable symbols for embedding in the host media signal, the message having two or more message components;

encrypting message components with different encryption keys to form an encrypted signal; and

modifying the host media signal based on the encrypted signal to steganographically hide the encrypted signal in the host media signal.

2. The method of claim 1 including using the different encryption keys to generate different carrier signals for the message components.

3. The method of claim 1 including using the different encryption keys to generate different mappings of the message components to attributes of the host media signal.

4. The method of claim 1 wherein the encrypted signal comprises elements that correspond to attributes of the host media signal, and including modifying attributes of the host media signal such that the modified attributes correspond to the encrypted signal.

5. The method of claim 4 wherein the attributes comprise attributes of sets of samples of the host media signal.

6. The method of claim 4 including modifying attributes by quantizing the attributes so that the quantized attribute corresponds to an embedded element of the encrypted signal.

7. The method of claim 5 including modifying attributes by quantizing the attributes so that the quantized attribute corresponds to an embedded element of the encrypted signal.

8. The method of claim 1 including providing error detection data for at least one of the message components such that the message component can be verified after decryption by the corresponding decryption key.

9. A method of embedding a digital watermark in a host media signal, the method comprising:

receiving a message comprising variable symbols for embedding in the host media signal,

encrypting the message with an encryption key to form an encrypted signal, the encrypted signal comprising elements that correspond to attributes of the host media signal; and

modifying the host media signal based on the encrypted signal to steganographically hide the encrypted signal in the host media signal, including quantizing attributes of the host media signal such that the modified attributes correspond to the encrypted signal, the attributes corresponding to sets of samples of the host media signal.

10. The method of claim 9 including embedding an un-encrypted component of the digital watermark in addition to the encrypted signal in the host media signal.

11. The method of claim 10 wherein the un-encrypted component comprises orientation data used to determine orientation of the digital watermark in the host media signal.

12. The method of claim 9 wherein the host media signal comprises an image signal.

13. A method of decoding a digital watermark that has been steganographically encoded in a host media signal, the method comprising:

using different encryption keys to generate different decoding signals for extracting an encoded message in the digital watermark;

using the different decoding signals to extract estimates of the encoded message; and

using error detection to determine whether the estimates are valid.

14. The method of claim 13 wherein the different encryption keys are used to generate different carrier signals used in decoding the digital watermark.

15. The method of claim 13 wherein the different encryption keys are used to decrypt different components of the digital watermark signal.

16. The method of claim 13 wherein the different encryption keys are used to generate different mappings of the digital watermark to attributes of the host media signal, and the different mappings are used in decoding the digital watermark.

17. A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform a method of embedding a digital watermark in a host media signal, the method comprising:

receiving a message comprising variable symbols for embedding in the host media signal, the message having two or more message components;

encrypting message components with different encryption keys to form an encrypted signal; and

modifying the host media signal based on the encrypted signal to steganographically hide the encrypted signal in the host media signal.

18. A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform a method of embedding a digital watermark in a host media signal, the method comprising:

receiving a message comprising variable symbols for embedding in the host media signal,

encrypting the message with an encryption key to form an encrypted signal, the encrypted signal comprises elements that correspond to attributes of the host media signal; and

modifying the host media signal based on the encrypted signal to steganographically hide the encrypted signal in the host media signal, including quantizing attributes of the host media signal such that the modified attributes correspond to the encrypted signal, the attributes corresponding to sets of samples of the host media signal.

19. A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform a method of decoding a digital watermark that has been steganographically encoded in a host media signal, the method comprising:

using different encryption keys to generate different decoding signals for extracting an encoded message in the digital watermark;

using the different decoding signals to extract estimates of the encoded message; and

using error detection to determine whether the estimates are valid.