Optimization methods for the insertion, protection, and detection of digital watermarks in digital data

• US 20010029580A1
• Filed: 02/22/2001
• Published: 10/11/2001
• Est. Priority Date: 07/02/1996
• Status: Active Grant

• Current Assignee: Wistaria Trading Inc.
• Original Assignee: Wistaria Trading Inc.
• Inventors: Moskowitz, Scott A.
• Granted Patent: US 7,107,451 B2
• Time in Patent Office: Days
• US Class Current: 713/176
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06F 21/16 Program or content traceability, e.g. by watermarking
• CPC Class Codes: G06Q 20/3823 combining multiple encryption tools for a transaction
• CPC Class Codes: G06Q 30/06 Buying, selling or leasing transactions
• CPC Class Codes: H04L 2209/08 Randomization, e.g. dummy operations or using noise
• CPC Class Codes: H04L 2209/608 Watermarking
• CPC Class Codes: H04L 2463/101 applying security measures for digital rights management data processing systems or methods, specially adapted for commerce, e.g. marketing, shopping, billing, auctions or e-commerce G06Q30/00
• CPC Class Codes: H04L 2463/102 applying security measure for e-commerce data processing systems or methods, specially adapted for e-commerce G06Q30/00
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/12 Applying verification of the received information cryptographic mechanisms or cryptographic arrangements for data integrity or data verification H04L9/32
• CPC Class Codes: H04L 9/3297 involving time stamps, e.g. generation of time stamps
• 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 21/8358 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

Abstract

Disclosed herein are methods and systems for encoding digital watermarks into content signals. Also disclosed are systems and methods for detecting and/or verifying digital watermarks in content signals.

According to one embodiment, a system for encoding of digital watermark information includes: a window identifier for identifying a sample window in the signal; an interval calculator for determining a quantization interval of the sample window; and a sampler for normalizing the sample window to provide normalized samples.

According to another embodiment, a system for pre-analyzing a digital signal for encoding at least one digital watermark using a digital filter is disclosed.

According to another embodiment, a method for pre-analyzing a digital signal for encoding digital watermarks comprises: (1) providing a digital signal; (2) providing a digital filter to be applied to the digital signal; and (3) identifying an area of the digital signal that will be affected by the digital filter based on at least one measurable difference between the digital signal and a counterpart of the digital signal selected from the group consisting of the digital signal as transmitted, the digital signal as stored in a medium, and the digital signal as played backed.

According to another embodiment, a method for encoding a watermark in a content signal includes the steps of (1) splitting a watermark bit stream; and (2) encoding at least half of the watermark bit stream in the content signal using inverted instances of the watermark bit stream.

Other methods and systems for encoding/decoding digital watermarks are also disclosed.

(Attorney Docket No. 066112.0132), entitled “Method And Device For Monitoring And Analyzing Signals”; U.S. Provisional Patent Application No. 60/234,199, filed Sep. 20, 2000, (Attorney Docket No. 066112.9999), entitled “Improved Security Based on Subliminal and Supraliminal Channels For Data Objects”; and U.S. patent application Ser. No. 09/671,739, filed Sep. 29, 2000, (Attorney Docket No. 066112.999A), entitled “Method And Device For Monitoring And Analyzing Signals,” U.S. patent application Ser. No. 09/731,039 (Attorney Docket No. 031838.0008) entitled “System and Method for Permitting Open Access to Data Objects and For Securing Data Within the Data Objects,” filed Dec. 7, 2000; and U.S. patent Application Ser. No. 09/731,040 (Attorney Docket No. 031838.0010), entitled “Systems, Methods and Devices for Trusted Transactions,” filed Dec. 7, 2000. The previously identified patents and/or patent applications are hereby incorporated by reference, in their entireties.

In addition, this application hereby incorporates by reference, as if fully stated herein, the disclosures of U.S. Pat. No. 5,613,004 “Steganographic Method and Device”; U.S. Pat. No. 5,745,569 “Method for Stega-Cipher Protection of Computer Code”; U.S. Pat. No. 5,889,868 “Optimization Methods for the Insertion, Protection, and Detection of Digital Watermarks in Digitized Data”; and U.S. Pat. No. 6,078,664, entitled “Z-Transform Implementation of Digital Watermarks.”

Claims

1. A system for encoding of digital watermark information in a signal, comprising:

a window identifier for identifying a sample window in the signal;

an interval calculator for determining a quantization interval of the sample window, where the quantization interval is used to quantize normalized window samples; and

a sampler for normalizing the sample window to provide normalized samples, where the normalized samples conform to a limited range of values that are proportional to real sample values and comprise a representation of the real sample values with a resolution higher than the real range of values, and where the normalized values can be divided by the quantization interval into distinct quantization levels.

2. The system of

claim 1

, further comprising:

an analyzer for analyzing the normalized samples to determine quantization levels;

a comparator for comparing a plurality of message bits in the signal to the corresponding quantization level information;

an adjuster for adjusting the quantization level of the sample window to correspond to the message bit when a bit conflicts with the quantization level; and

a denormalizer for de-normalizing the analyzed normalized samples.

3. The system of

claim 1

, further comprising:

a quantization level analyzer for analyzing the quantization level of the samples to determine a message bit value.

4. The system of

claim 1

, further comprising:

a processor for identifying a plurality of candidate bits in the signal that can be manipulated.

5. The system of

claim 4

, further comprising:

an encoder for randomly encoding watermark bits in the signal; and

a filter;

wherein fewer than a total number of available candidate bits are encoded as determined by the filter.

6. The system of

claim 5

, wherein the filter comprises at least one of a primary mask, a convolution mask, and a message delimiter mask.

7. The system of

claim 5

, wherein the filter comprises an optical filter.

8. The system of

claim 5

, wherein the filter comprises an optimal digital filter.

9. The system of

claim 5

, wherein the encoder encodes additional bits in the signal, which additional bits are unrelated to the watermark bits, and which additional bits serve to introduce noise into the signal.

10. The system of

claim 5

, further comprising:

a decorrelator for decorrelating additional bits using a dither technique.

11. The system of

claim 5

, wherein the candidate bits are selected from the group consisting of watermark bits and message delimiter bits.

12. A system for pre-analyzing a digital signal for encoding at least one digital watermark using a digital filter comprising:

a processor for identifying an area of the digital signal that will be affected by the digital filter; and

an encoder for encoding the at least one digital watermark in the digital signal, the encoder encoding the at least one digital watermark so as to avoid the at least one area of the digital signal that will be affected by the digital filter.

13. The system of

claim 12

, wherein the processor operates on the digital signal by selecting an area of the digital signal from the group consisting of a frequency delimited area and a time delimited area.

14. The system of

claim 12

, wherein the processor operates on the digital signal by selecting an area of the digital signal from a bit-depth delimited area.

15. The system of

claim 12

, wherein the encoder ensures that the watermark will survive the changes introduced by the digital filter.

16. A system for pre-processing a watermark message, comprising:

a pre-processor for determining an exact length of a watermark message as it will be encoded;

a key generator for generating a watermark key that provides at least one unique bit for each bit comprising the watermark message.

17. A system for encoding a watermark in a digital signal, comprising:

a generator for generating a plurality of watermark pseudo-random key bits; and

an encoder for encoding the watermark in the digital signal using the watermark pseudo-random key bits and characteristics of the digital signal.

18. The system of

claim 17

, wherein the generator is selected from the group consisting of a non-linear generator and a chaotic generator.

19. The system of

claim 17

, wherein the characteristics of the digital signal comprise mathematically defined functions of the digital signal.

20. A system for encoding a watermark in a digital signal, comprising:

a mapper for mapping pseudo-random key and processing state information to effect an encode/decode map using a generator; and

an encoder for encoding the watermark in the digital signal using the encode/decode map and characteristics of the digital signal.

21. The system of

claim 20

, wherein the generator is selected from the group consisting of a non-linear generator and a chaotic generator.

22. The system of

claim 20

, wherein the characteristics of the digital signal comprise mathematically defined functions of the digital signal.

23. A system for encoding watermarks, comprising:

an inverter for inverting at least one instance of the watermark bit stream; and

an encoder for encoding at least one instance of the watermark using the inverted instance of the watermark bit stream.

24. A system for analyzing composite digitized signals for watermarks, comprising:

a first receiver for receiving a composite signal;

a second receiver for receiving an unwatermarked sample signal;

an aligner for time aligning the unwatermarked sample signal with the composite signal;

an adjuster for gain adjusting the time aligned unwatermarked sample signal to a corresponding segment of the composite signal, determined when the signals are time aligned;

an estimator for estimating a pre-composite signal using the composite signal and the gain adjusted unwatermarked sample signal;

an estimator for estimating a watermarked sample signal by subtracting the estimated pre-composite signal from the composite signal; and

a scanner for scanning the estimated watermarked sample signal for watermarks.

25. A method for pre-analyzing a digital signal for encoding a plurality of digital watermarks using a digital filter, comprising:

providing a digital signal;

providing a plurality of digital watermarks; and

determining an encoding level; and

encoding each of the plurality of digital watermarks in the digital signal at substantially the same encoding level.

26. A method for pre-analyzing a digital signal for encoding digital watermarks using a digital filter, comprising:

providing a digital signal;

providing a digital filter to be applied to the digital signal; and

identifying an area of the digital signal that will be affected by the digital filter based on at least one measurable difference between the digital signal and a counterpart of the digital signal selected from the group consisting of the digital signal as transmitted, the digital signal as stored in a medium, and the digital signal as played backed.

27. A method for encoding a watermark in a content signal, comprising:

splitting a watermark bit stream; and

encoding at least half of the watermark bit stream in the content signal using inverted instances of the watermark bit stream.

28. A method for encoding at least one watermark in a content signal, comprising:

predetermining a number of bits in the content signal to be encoded, based on at least one of a fixed length key and signal characteristics of the content signal; and

encoding the watermark in the predetermined bits.

29. A method for encoding at least one watermark in a content signal, comprising:

locating at least one noise-like signal feature in the content signal; and

encoding the at least one watermark in substantially the same location as the at least one noise-like signal feature.

30. A method for encoding at least one digital watermark in a content signal comprising:

measuring a perceived signal-to-error ratio; and

encoding the at least one watermark in a channel bound by a minimum and maximum signal-to-error level for the content signal.

31. A method for digital watermark encode/decode comprising the steps of:

measuring a perceived signal-to-error ratio; and

encoding at least one watermark in a signal feature that is bound by a minimum and maximum signal-to-error level for the digital signal.

32. A method for digital watermark decode comprising:

receiving a suspect digital signal to be analyzed;

subjecting the digital signal to a time-based alignment;

using the time-based alignment to align amplitude values in the suspect digital signal; and

decoding a digital watermark.

33. A method for encoding watermarks in a digital content signal, comprising:

identifying a plurality of signal features in the digital content signal; and

inserting watermark data in the identified signal features;

wherein the identified signal features are identified from relationships between multiple sample windows in the digital content signal.

34. The method of

claim 33

, wherein the signal features have logical relationships with an analog waveform represented by the digital content signal.

35. The method of

claim 33

, wherein the signal features comprise mathematical functions of the sample windows.

36. A method for decoding watermarks from a digital content signal, comprising:

identifying a plurality of signal features in the digital content signal; and

decoding watermark data from the signal features;

wherein the signal features are identified from relationships between multiple sample windows in the digital content signal.

37. The method of

claim 36

, wherein the signal features have logical relationships with an analog waveform represented by the digital content signal.

38. The method of

claim 36

, wherein the signal features comprise mathematical functions of the sample windows.

39. A method for pre-analyzing a digital signal for encoding digital watermarks using a digital filter comprising:

identifying at least one of a frequency and a time delimited area of the digital signal that will be affected by the digital filter; and

encoding at least one digital watermark so as to avoid the identified area.

40. A method for pre-analyzing a digital signal for encoding digital watermarks using a digital filter, comprising:

identifying at least one change to the digital signal that will be affected by the digital filter; and

encoding at least one digital watermark so the watermark survives the changes introduced by the digital filter.

41. A method for guaranteeing watermark uniqueness, comprising:

providing a watermark; and

attaching a timestamp to the watermark.

42. A method for guaranteeing watermark uniqueness, comprising:

providing a watermark; and

attaching a user identification dependent hash to the watermark.

43. A method for guaranteeing watermark uniqueness, comprising:

providing a watermark; and

attaching a message digest of watermark data to the watermark.

44. A system for digital watermark encode/decode operations, comprising:

a CODEC database comprising a plurality of CODECs; and

a processor which encodes at least one watermark using at least one CODECs from the CODEC database.

45. The system of

claim 44

wherein the processor encodes a plurality of watermarks using a at least two CODECs from the CODEC database, and wherein the processor stores each of the CODECs to the watermarking key.

46. The system of

claim 45

wherein the processor generates a hash value for information regarding the CODEC used to encode the plurality of watermarks and attaches the hash value to the watermark.

47. A method for digital watermark encode/decode comprising;

providing a digital signal stream;

using one or more of a plurality of watermarking CODECs to encode at least one digital watermark; and

associating the one or more of a plurality of watermarking CODECs with a predetermined key.

48. An article of manufacture comprising:

a receiver to receive a digital signal;

a detector to detect at least two of a plurality of digital watermarks located within the digital signal; and

a processor that enables content signal manipulation of the digital signal based on successful detection of at least two of the plurality of digital watermarks.

49. The article of

claim 48

, wherein the detector also detects a watermark , further comprising:

a verification module which verifies at least one detected watermark .

50. A method for pre-processing a digital data signal to authorize a plurality of unique descendant copies of the digital data signal, comprising:

providing the digital data signal;

identifying a plurality of candidate bits in the digital data signal that can be manipulated during embedding;

generating a digital watermark message to be embedded based on at least one predetermined criterion; and

embedding the digital watermark message in the plurality of candidate bits.

51. The method of

claim 50

, wherein the step of identifying candidate bits of the digital data signal to be manipulated comprises:

generating a psychoacoustic model of the digital data signal.

52. The method of

claim 50

, wherein the step of identifying candidate bits of the digital data signal to be manipulated comprises:

generating a psychovisual model of the digital data signal.

53. The method of

claim 50

, wherein the digital data signal comprises compressed digital data.

54. The method of

claim 50

, wherein the step of generating a digital watermark message comprises:

generating a unique digital watermark message for each authorized descendant copy.

55. The method of

claim 50

, wherein the criterion are selected from the group consisting of a geographical territory, a transaction identification, an individual identification, a use limitation, and a signal domain.

56. The method of

claim 50

, wherein the digital watermark message is encoded in a subset of the plurality of candidate bits identified.

57. The method of

claim 50

, wherein the plurality of candidate bits that are embedded with the digital watermark message have a relationship that creates additional uniqueness of the digital watermark message.

58. The method of

claim 57

, wherein the relationship is at least one of a sequential relationship, a linear relationship, and a logically-ordered relationship.

59. The method of

claim 50

, wherein a subset of the plurality of the candidate bits share at least one function.

60. The method of

claim 59

, wherein the function is selected from the group consisting of mapping, error correction, and signal processing.

61. The method of

claim 50

further comprising:

selectively adding noise to the digital data signal.

62. A method for pre-processing a digital data signal to authorize a plurality of unique descendant copies of the digital data signal, comprising:

providing a digital data signal;

identifying candidate bits of the digital data signal that will be manipulated during scrambling;

generating a key on at least one predetermined criterion; and

manipulating the digital data signal at the plurality of candidate bits with the scrambling key.

63. The method of

claim 62

, wherein the step of identifying candidate bits of the digital data signal to be manipulated comprises:

generating a psychoacoustic model of the digital data signal.

64. The method of

claim 62

, wherein the step of identifying candidate bits of the digital data signal to be manipulated comprises:

generating a psychovisual model of the digital data signal.

65. The method of

claim 62

, wherein the step of providing a digital data signal comprises providing a digital data signal comprised of compressed digital data.

66. The method of

claim 62

, wherein the step of generating a scrambling key comprises:

generating a unique scrambling key for each authorized descendant copy.

67. The method of

claim 62

, wherein the criterion are selected from the group consisting of a geographical territory, a transaction identification, an individual identification, a use limitation, and a signal domain.

68. The method of

claim 62

, wherein a subset of the plurality of candidate bits identified are manipulated with the key.

69. The method of

claim 62

, wherein the step of manipulating the digital data signal at the plurality of candidate bits with the scrambling key comprises:

manipulating the plurality of candidate bits with a key to embed a watermark and to add noise to digital signal.

70. The method of

claim 69

, wherein the relationship is at least one of a sequential relationship, a linear relationship, and a logically-ordered relationship.

71. The method of

claim 62

, wherein a subset of the plurality of the candidate bits are selected based upon their ability to survive a predetermined test of robustness.

72. The method of

claim 71

, wherein the function is selected from the group consisting of mapping, error correction, and signal processing.

73. A method for creating a descendant copy of a digital data signal, comprising:

obtaining a model for the digital data signal; and

generating a watermark for the descendant copy of the digital data signal based on at least one criterion.

74. The method of

claim 73

, wherein the step of obtaining a model of the digital data signal comprises:

generating the psychoacoustic model for the digital data signal.

75. The method of

claim 73

, wherein the step of obtaining a model of the digital data signal comprises:

retrieving a stored psychoacoustic model for the digital data signal.

76. The method of

claim 73

, wherein the step of obtaining a model of the digital data signal comprises:

generating the psychovisual model for the digital data signal.

77. The method of

claim 73

, wherein the step of obtaining a model of the digital data signal comprises:

retrieving a stored psychovisual model for the digital data signal.

78. The method of

claim 73

, wherein the criterion are selected from the group consisting of a geographical territory, a transaction identification, an individual identification, a use limitation, and a signal domain.

79. A method for pre-processing a digital data signal, comprising:

providing a digital signal;

identifying a plurality of candidate bits in the digital data signal that can be manipulated during embedding;

generating at least one digital watermark message to be embedded based on at least one predetermined criterion;

selecting candidate bits to manipulate; and

embedding the at least one digital watermark message in the selected candidate bits.

80. The method of

claim 79

, wherein the at least one predetermined criterion includes at least one characteristic of the digital signal.

81. The method of

claim 79

, wherein the step of selecting candidate bits to manipulate comprises:

selecting candidate bits that provide optimal locations for the digital watermark.

82. The method of

claim 79

, further comprising the step of:

inverting at least one watermark out of a plurality of embedded watermarks.

83. The method of

claim 79

, further comprising the step of:

decoding the at least one digital watermark from the digital data signal.

84. The method of

claim 83

, wherein the step of decoding the at least one digital watermark from the digital data signal comprises:

degrading the watermarked digital data signal responsive to an unauthorized attempt to decode the digital watermark form the digital data signal.

85. The method of

claim 83

, wherein the step of decoding the at least one digital watermark from the digital data signal comprises:

degrading the watermarked digital signal responsive to fewer than all embedded watermarks being decoded from the digital signal.

86. The method of

claim 83

, wherein the step of decoding the at least one digital watermark from the digital data signal is asymmetric.

87. The method of

claim 79

, wherein a key corresponding each of the at least one watermark comprises a greater number of bits than the corresponding watermark message. 88. The method of

claim 79

, wherein a key corresponding each of the at least one watermark comprises the same greater number of bits as the corresponding watermark message.