Method and apparatus for fingerprinting and authenticating various magnetic media

• US 5,546,462 A
• Filed: 09/09/1994
• Issued: 08/13/1996
• Est. Priority Date: 04/09/1993
• Status: Expired due to Term

• Current Assignee: Washington University In St Louis
• Original Assignee: Washington University In St Louis
• Inventors: Hege, Alan L., Indeck, Ronald S., Muller, Marcel W., Engel, George Lawrence
• Primary Examiner(s): Cain, David C.
• Application Number:
  US08/303,690
• Time in Patent Office: 704 Days
• Field of Search: 380/22, 380/23, 380/3, 380/4, 235/493, 235/449, 360/2
• US Class Current: 713/176
• CPC Class Codes: G06F 21/101 by binding digital rights to specific entities
• CPC Class Codes: G06F 21/16 Program or content traceability, e.g. by watermarking
• CPC Class Codes: G06F 21/79 in semiconductor storage media, e.g. directly-addressable memories
• CPC Class Codes: G06F 2211/007 Encryption, En-/decode, En-/decipher, En-/decypher, Scramble, (De-)compress
• CPC Class Codes: G06K 1/125 by magnetic means
• CPC Class Codes: G06K 19/12 the marking being sensed by magnetic means
• CPC Class Codes: G06Q 20/347 Passive cards
• CPC Class Codes: G06Q 20/3674 involving authentication
• CPC Class Codes: G07D 7/004 using digital security elements, e.g. information coded on a magnetic thread or strip
• CPC Class Codes: G07D 7/04 Testing magnetic properties of the materials thereof, e.g. by detection of magnetic imprint G07D7/01 takes precedence
• 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 7/0813 Specific details related to card security
• 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 7/125 Offline card verification
• 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 20/00094 involving measures which result in a restriction to authorised record carriers
• CPC Class Codes: G11B 20/00123 the record carrier being identified by recognising some of its unique characteristics, e.g. a unique defect pattern serving as a physical signature of the record carrier
• CPC Class Codes: G11B 23/281 by changing the physical properties of the record carrier
• CPC Class Codes: G11B 23/283 Security features, e.g. digital codes
• CPC Class Codes: G11B 23/284 on the record carrier
• CPC Class Codes: G11B 5/00 : Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor G11B11/00 and G11B13/00 take precedence

Abstract

A method and apparatus is disclosed for determining the remanent noise in a magnetic medium by, for example, DC saturation of a region thereof and measurement of the remaining DC magnetization. A conventional magnetic recording transducer may be used to determine the remanent noise. Upon determination, the remanent noise may then be digitized and recorded on the same magnetic medium to thereby "fingerprint" the magnetic medium. This "fingerprint" may then be later used to verify and authenticate the magnetic medium as being an original. The magnetic medium may be of a type adapted to record information magnetically or, even more broadly, any magnetic surface or substance that can be sensed through its magnetic field. In such manner, any magnetic medium, or any object having an associated magnetic medium, may be "fingerprinted" including credit cards, computer program diskettes, magneto-optic discs, videotapes, cassette tapes, bank checks, stock certificates, etc.

Claims

1. A device for fingerprinting an object for the later determination of its identity, said object including at least in part, a non-recording magnetic medium portion, said device having means for determining a remanent noise for said non-recording magnetic medium portion, said remanent noise comprising the fingerprint for said object, and means for recording said remanent noise for later comparison with the later determination of said remanent noise to thereby identify said object.

2. The device of claim 1 wherein said recording means has means for recording said fingerprint on said object.

3. The device of claim 2 wherein said recording means includes means for embodying said remanent noise in said non-recording magnetic medium portion in machine readable form.

4. The device of claim 3 further comprising means for encrypting said remanent noise prior to its being recorded by said recording means.

5. The device of claim 4 wherein said object is a financial instrument.

6. The device of claim 5 wherein said non-recording magnetic medium portion comprises at least a portion of a character applied to said financial instrument.

7. The device of claim 6 wherein said financial instrument is a bank check.

8. The device of claim 7 wherein said remanent noise is encrypted with a trap door function.

9. The device of claim 2 wherein said non-recording magnetic medium portion comprises a label affixed to said object.

18. The device of claim 1 wherein said determining means includes means for DC saturating a region of said non-recording magnetic medium and means for reading a residual voltage over said region, said residual voltage comprising said remanent noise.

19. The device of claim 18 wherein said region comprises a linear portion extending between about 30 micrometers and about 4300 micrometers.

20. The device of claim 18 wherein said determining means further comprises means for averaging a plurality of residual voltage readings, said average comprising said fingerprint.

21. The device of claim 1 wherein said determining means comprises a conventional magnetic recording head.

10. An object having its fingerprint recorded for the later verification of its identity, said object having a non-recording magnetic medium portion, said finger-print comprising a remanent noise for said non-recording magnetic medium portion.

11. The object of claim 10 wherein said fingerprint is recorded on said object.

12. The object of claim 11 wherein said remanent noise is recorded in said non-recording magnetic medium portion in machine readable form.

13. The object of claim 12 wherein said remanent noise is encrypted prior to its being recorded on said object.

14. The object of claim 13 wherein said object is a financial instrument.

15. The object of claim 14 wherein said non-recording magnetic medium portion comprises at least a portion of a character applied to said financial instrument.

16. The object of claim 15 wherein said financial instrument is a bank check.

17. The object of claim 10 wherein said magnetic medium portion comprises a label affixed to said object.

22. A device for authenticating an object having a fingerprint recorded, said object having a non-recording magnetic medium portion, said fingerprint comprising a remanent noise for said non-recording magnetic medium portion, said device including means for reading said recorded fingerprint, means for translating said remanent noise from said recorded fingerprint, means for determining a remanent noise directly from said non-recording magnetic medium portion, and means for comparing said translated remanent noise with said determined remanent noise to determine whether they match, thereby authenticating said object.

23. The device of claim 22 wherein said object has its fingerprint recorded thereon.

24. The device of claim 22 wherein said fingerprint is embodied in said non-recording magnetic medium portion in machine readable form.

25. The device of claim 24 wherein said fingerprint is encrypted, and said translation means includes means for de-crypting said fingerprint.

26. The device of claim 25 wherein said object is a financial instrument.

27. The device of claim 26 wherein said non-recording magnetic medium portion comprises at least a portion of a character applied to said financial instrument.

28. The device of claim 27 wherein said financial instrument is a bank check.

29. The device of claim 25 wherein said remanent noise is encrypted with a trap door function.

30. The device of claim 22 wherein said non-recording magnetic medium portion comprises a label affixed to said object.

31. A method for authenticating an object, said object including at least in part a non-recording magnetic medium portion, said object having a fingerprint recorded, said fingerprint comprising a previously determined remanent noise for said non-recording magnetic medium portion, said method comprising the steps of:

determining a remanent noise directly from said non-recording magnetic medium portion,

reading said fingerprint, and

comparing said determined remanent noise with said fingerprint.

32. The method of claim 31 wherein said fingerprint comprises a machine readable representation of said previously determined remanent noise, and the step of reading includes the step of reading said fingerprint with a machine.

33. The method of claim 32 wherein said fingerprint comprises an encrypted representation of said previously determined remanent noise, and further comprising the step of de-crypting said fingerprint.

34. A method for fingerprinting an object for the later determination of its identity, said object including at least in part a non-recording magnetic medium portion, said method comprising the steps of determining a remanent noise for said non-recording magnetic medium portion, said remanent noise comprising said fingerprint, and recording said fingerprint on said object for the later comparison thereof with the later determination of said remanent noise.

35. The method of claim 34 further comprising the step of encrypting said fingerprint prior to recording.

36. A device for fingerprinting an object for the later determination of its identity, said object including at least in part, a non-recording magnetic medium portion, said device having means for determining a remanent noise for a length of no more than about several hundreds of micrometers of said non-recording magnetic medium portion, said remanent noise comprising the fingerprint for said object, and means for recording said remanent noise for later comparison with the later determination of said remanent noise to thereby identify said object.

37. The device of claim 36 wherein said recording means has means for recording said fingerprint on said object.

38. The device of claim 37 Wherein said recording means includes means for embodying said remanent noise in said non-recording magnetic medium portion in machine readable form.

39. The device of claim 38 further comprising means for encrypting said remanent noise prior to its being recorded by said recording means.

40. The device of claim 39 wherein said object is a financial instrument.

41. The device of claim 40 wherein said non-recording magnetic medium portion comprises at least a portion of a character applied to said financial instrument.

42. A device for fingerprinting an object for the later determination of its identity, said object including at least in part, a non-recording magnetic medium portion, said device having means for determining a remanent noise from a magnetic micro-structure for said nonrecording magnetic medium portion, said remanent noise comprising the fingerprint for said object, and means for recording said remanent noise for later comparison with the later determination of said remanent noise to thereby identify said object.

43. The device of claim 42 wherein said recording means has means for recording said fingerprint on said object.

44. The device of claim 43 wherein said recording means includes means for embodying said remanent noise in said non-recording magnetic medium portion in machine readable form.

45. The device of claim 44 further comprising means for encrypting said remanent noise prior to its being recorded by said recording means.

46. The device of claim 42 wherein said object is a financial instrument.

47. The device of claim 46 wherein said non-recording magnetic medium portion comprises at least a portion of a character applied to said financial instrument.

48. A device for fingerprinting an object for the later determination of its identity, said object including at least in part, a uniformly manufactured non-recording magnetic medium portion, said device having means for determining a remanent noise for said non-recording magnetic medium portion, said remanent noise comprising the fingerprint for said object, and means for recording said remanent noise for later comparison with the later determination of said remanent noise to thereby identify said object.

49. The device of claim 48 wherein said recording means has means for recording said fingerprint on said object.

50. The device of claim 49 wherein said recording means includes means for embodying said remanent noise in said non-recording magnetic medium portion in machine readable form.

51. The device of claim 48 wherein said object is a financial instrument.

52. The device of claim 51 wherein said non-recording magnetic medium portion comprises at least a portion of a character applied to said financial instrument.

53. An object having its fingerprint recorded for the later verification of its identity, said object having a non-recording magnetic medium portion, said fingerprint comprising a remanent noise for no more than about several hundreds of micrometers of said non-recording magnetic medium portion.

54. The object of claim 53 wherein said fingerprint is recorded on said object.

55. The object of claim 54 wherein said remanent noise is embodied in said non-recording magnetic medium portion in machine readable form.

56. The object of claim 55 wherein said remanent noise is encrypted prior to its being recorded on said object.

57. The device of claim 53 wherein said object is a financial instrument.

58. The device of claim 57 wherein said non-recording magnetic medium portion comprises at least a portion of a character applied to said financial instrument.

59. An object having its fingerprint recorded for the later verification of its identity, said object having a non-recording magnetic medium portion, said fingerprint comprising a remanent noise from a magnetic microstructure for said non-recording magnetic medium portion.

60. The object of claim 59 wherein said fingerprint is recorded on said object.

61. The object of claim 60 wherein said remanent noise is embodied in said non-recording magnetic medium portion in machine readable form.

62. The object of claim 61 wherein said remanent noise is encrypted prior to its being recorded on said object.

63. The device of claim 59 wherein said object is a financial instrument.

64. The device of claim 63 wherein said non-recording magnetic medium portion comprises at least a portion of a character applied to said financial instrument.

65. An object having its fingerprint recorded for the later verification of its identity, said object having a uniformly manufactured non-recording magnetic medium portion, said fingerprint comprising a remanent noise for said non-recording magnetic medium portion.

66. The object of claim 65 wherein said fingerprint is recorded on said object.

67. The object of claim 66 wherein said remanent noise is embodied in said non-recording magnetic medium portion in machine readable form.

68. The object of claim 67 wherein said remanent noise is encrypted prior to its being recorded on said object.

69. The device of claim 65 wherein said object is a financial instrument.

70. The device of claim 69 wherein said non-recording magnetic medium portion comprises at least a portion of a character applied to said financial instrument.

71. A device for authenticating an object having a fingerprint recorded, said object having a non-recording magnetic medium portion, said fingerprint comprising a remanent noise for a length of no more than about several hundreds of micrometers of said non-recording magnetic medium portion, said device including means for reading said recorded fingerprint, means for translating said remanent noise from said fingerprint, means for determining a remanent noise directly from said non-recording magnetic medium portion, and means for comparing said translated remanent noise with said determined remanent noise to determine whether they match, thereby authenticating said object.

72. The device of claim 71 wherein said object has its fingerprint recorded thereon.

73. The device of claim 72 wherein said fingerprint is embodied in said non-recording magnetic medium portion in machine readable form.

74. The device of claim 73 wherein said fingerprint is encrypted, and said translation means includes means for de-crypting said fingerprint.

75. The device of claim 71 wherein said object is a financial instrument.

76. The device of claim 75 wherein said non-recording magnetic medium portion comprises at least a portion of a character applied to said financial instrument.

77. A device for authenticating an object having a fingerprint recorded, said object having a non-recording magnetic medium portion, said fingerprint comprising a remanent noise from a magnetic micro-structure for said non-recording magnetic medium portion, said device including means for reading said recorded fingerprint, means for translating said remanent noise from said fingerprint, means for determining a remanent noise directly from said non-recording magnetic medium portion, and means for comparing said translated remanent noise with said determined remanent noise to determine whether they match, thereby authenticating said object.

78. The device of claim 77 wherein said object has its fingerprint recorded thereon.

79. The device of claim 77 wherein said fingerprint is embodied in said non-recording magnetic medium portion in machine readable form.

80. The device of claim 79 wherein said fingerprint is encrypted, and said translation means includes means for de-crypting said fingerprint.

81. The device of claim 77 wherein said object is a financial instrument.

82. The device of claim 81 wherein said non-recording magnetic medium portion comprises at least a portion of a character applied to said financial instrument.

83. A device for authenticating an object having a fingerprint recorded, said object having a uniformly manufactured non-recording magnetic medium portion, said fingerprint comprising a remanent noise for said nonrecording magnetic medium portion, said device including means for reading said recorded fingerprint, means for translating said remanent noise from said fingerprint, means for determining a remanent noise directly from said non-recording magnetic medium portion, and means for comparing said translated remanent noise with said determined remanent noise to determine whether they match, thereby authenticating said object.

84. The device of claim 83 wherein said object has its fingerprint recorded thereon.

85. The device of claim 83 wherein said fingerprint is embodied in said non-recording magnetic medium portion in machine readable form.

86. The device of claim 85 wherein said fingerprint is encrypted, and said translation means includes means for de-crypting said fingerprint.

87. The device of claim 83 wherein said object is a financial instrument.

88. The device of claim 87 wherein said non-recording magnetic medium portion comprises at least a portion of a character applied to said financial instrument.

89. A method for authenticating an object, said object including at least in part a non-recording magnetic medium portion, said object having a fingerprint recorded, said fingerprint comprising a previously determined remanent noise for a length of no more than about several hundreds of micrometers of said non-recording magnetic medium portion, said method comprising the steps of:

determining a remanent noise directly from said non-recording medium portion,

reading said fingerprint, and

correlating said determined remanent noise with said fingerprint, said correlation thereby indicating if said object is authentic.

90. The method of claim 89 wherein said fingerprint comprises a machine readable representation of said previously determined remanent noise, and the step of reading includes the step of reading said fingerprint with a machine.

91. The method of claim 90 wherein said fingerprint comprises an encrypted representation of said previously determined remanent noise, and further comprising the step of de-crypting said fingerprint.

92. A method for authenticating an object, said object including at least in part a non-recording magnetic medium portion, said object having a fingerprint recorded, said fingerprint comprising a previously determined remanent noise from a magnetic micro-structure for said non-recording magnetic medium portion, said method comprising the steps of:

determining a remanent noise directly from said non-recording medium portion,

reading said fingerprint, and

correlating said determined remanent noise with said fingerprint, said correlation thereby indicating if said object is authentic.

93. The method of claim 92 wherein said fingerprint comprises a machine readable representation of said previously determined remanent noise, and the step of reading includes the step of reading said fingerprint with a machine.

94. The method of claim 93 wherein said fingerprint comprises an encrypted representation of said previously determined remanent noise, and further comprising the step of de-crypting said fingerprint.

95. A method for authenticating an object, said object including at least in part a uniformly manufactured non-recording magnetic medium portion, said object having a fingerprint recorded, said fingerprint comprising a previously determined remanent noise for said nonrecording magnetic medium portion, said method comprising the steps of:

determining a remanent noise directly from said non-recording magnetic medium portion,

reading said fingerprint, and

correlating said determined remanent noise with said fingerprint, said correlation thereby indicating if said object is authentic.

96. The method of claim 95 wherein said fingerprint comprises a machine readable representation of said previously determined remanent noise, and the step of reading includes the step of reading said fingerprint with a machine.

97. The method of claim 96 wherein said fingerprint comprises an encrypted representation of said previously determined remanent noise, and further comprising the step of de-crypting said fingerprint.

98. A method for fingerprinting an object for the later determination of its identity, said object including at least in part a non-recording magnetic medium portion, said method comprising the steps of determining a remanent noise for a length of no more than about several hundreds of micrometers of said non-recording magnetic medium portion, said remanent noise comprising said fingerprint, and recording said fingerprint on said object for the later comparison thereof with the later determination of said remanent noise.

99. The method of claim 98 further comprising the step of encrypting said fingerprint prior to recording.

100. A method for fingerprinting an object for the later determination of its identity, said object including at least in part a non-recording magnetic medium portion, said method comprising the steps of determining a remanent noise from a magnetic micro-structure for said non-recording magnetic medium portion, said remanent noise comprising said fingerprint, and recording said fingerprint on said object for the later comparison thereof with the later determination of said remanent noise.

101. The method of claim 100 further comprising the step of encrypting said fingerprint prior to recording.

102. A method for fingerprinting an object for the later determination of its identity, said object including at least in part a uniformly manufactured non-recording magnetic medium portion, said method comprising the steps of determining a remanent noise for said non-recording magnetic medium portion, said remanent noise comprising said fingerprint, and recording said fingerprint on said object for the later comparison thereof with the later determination of said remanent noise.

103. The method of claim 102 further comprising the step of encrypting said fingerprint prior to recording.

104. A device for authenticating an object having a fingerprint recorded, said object having a non-recording magnetic medium portion, said recorded fingerprint comprising a signal corresponding to a first read of a remanent noise in said non-recording magnetic medium portion, means for determining said fingerprint by a second read of said remanent noise in said non-recording magnetic medium portion, and means for comparing said recorded fingerprint with said determined fingerprint including means for compensating for differences between said first read and said second read to determine whether said fingerprints match, thereby authenticating said object.

105. The device of claim 104 wherein said compensating means includes means for compensating for differences between a speed at which each of said first read and said second read is performed.

106. The device of claim 105 wherein said speed compensation means includes means for adjusting a sampling rate at which said second read is performed.

107. The device of claim 106 wherein said adjusting means includes means for measuring the speed of said second read and comparing it with the speed of said first read.

108. The device of claim 105 wherein said speed compensation means includes means for oversampling said remanent noise during at least said second read.

109. The device of claim 108 wherein said speed compensation means includes means for adjusting a rate of said oversampling.

110. The device of claim 105 wherein each of said recorded and determined fingerprints comprises a digital sample of said remanent noise, and wherein said speed compensation means includes means for creating for said second read a digital sample approximately 100 times larger than the digital sample of said first read.

111. A method for authenticating an object, said object-including at least in part a non-recording magnetic medium portion having a fingerprint, said fingerprint comprising a remanent noise for said non-recording magnetic medium portion previously determined by a first read thereof, said method comprising the steps of:

determining a remanent noise directly from said magnetic medium portion by a second read thereof,

comparing said determined remanent noise with said previously determined remanent noise, and

compensating for differences between said first read and said second read to determine whether said fingerprints match, thereby authenticating said object.

112. The method of claim 111 wherein the step of compensating further includes the step of compensating for differences between a speed at which each of said first read and said second read is performed.

113. The method of claim 112 wherein the step of speed compensating further includes the step of adjusting a sampling rate at which said second read is performed.

114. The method of claim 113 wherein the step of adjusting includes the steps of measuring the speed of said second read and comparing it with the speed of said first read.

115. The method of claim 112 wherein the step of speed compensating further includes the step of oversampling said remanent noise during at least said second read.

116. The method of claim 115 wherein the step of speed compensating further includes the step of adjusting a rate of oversampling.

117. The method of claim 112 wherein each of said previously determined remanent noise and said determined remanent noise comprises a digital sample of said remanent noise, and wherein the step of speed compensating further comprises the step of creating for said second read a digital sample approximately 100 times larger than the digital sample of said first read.

118. An object having its fingerprint recorded for the later verification of its identity, said object having a non-recording magnetic medium portion, said fingerprint comprising a remanent noise for said non-recording magnetic medium portion determined by a first read of said non-recording magnetic medium portion, and a speed of said read being recorded in association with said fingerprint for later use in compensating for differences between a speed of a subsequent read and the speed of said first read.

119. The object of claim 118 further comprising a plurality of spaced timing marks on said non-recording magnetic medium portion so that a speed of said non-recording magnetic medium portion may be determined during a read.

120. A security card with a fingerprint for limiting access to a controlled access environment, said security card having a non-recording magnetic medium portion, said fingerprint comprising a remanent noise for said nonrecording magnetic medium portion, said security card being validated to permit access only upon a match of a subsequent determination of said fingerprint with a previously determined fingerprint.