USRE43658EExpiredUtility

Analog physical signature devices and methods and systems for using such devices to secure the use of computer resources

49
Assignee: GUTHERY SCOTT BPriority: Nov 3, 2003Filed: Jan 5, 2011Granted: Sep 11, 2012
Est. expiryNov 3, 2023(expired)· nominal 20-yr term from priority
G07C 9/37G06F 21/123
49
PatentIndex Score
0
Cited by
24
References
107
Claims

Abstract

A method for binding a computer program to an analog physical signature device to form an interactive system for controlling the use of the computer program, the method comprising the steps of providing instructions comprising the computer program, the instructions implementing an intended functionality, providing the analog physical signature device to which the computer program is to be bound, the analog physical signature device being operative, in response to an analog input, to transform the analog input into a consequent, dependent analog output, and replacing at least one code segment of the instructions representing a program expression, with an alternative code segment, the alternative code segment defining a predetermined digital input that is causally related to a predetermined analog input by means of the interactive system, the alternative code segment being operative, when encountered during execution of the instructions comprising the computer program, to cause the predetermined analog input to be communicated to the bound analog physical signature device by means of the interactive system, the bound analog physical signature device being operative to transform the predetermined analog input to a consequent, dependent analog output that is causally related to a consequent, dependent digital output by means of the interactive system, the alternative code segment being operative to perform program functionality dependent upon the predetermined digital input and the consequent, dependent digital output.

Claims

exact text as granted — not AI-modified
1. A method for binding a computer program to an analog physical signature device to define an interactive system that controls the use of the computer program for its intended purpose, the method comprising the steps of:
 (a) providing instructions comprising the computer program, the instructions implementing an intended functionality; 
 (b) providing the analog physical signature device to which the computer program is to be bound, the analog physical signature device being operative, in response to an analog input, to transform the analog input into a consequent, dependent analog output; and 
 (c) replacing a code segment of the computer program instructions representing a program expression with an alternative code segment, the alternative code segment defining a predetermined digital input that is causally related to a predetermined analog input by means of the interactive system; 
 (d) the alternative code segment being operative, when encountered during execution of the instructions comprising the computer program, to cause the predetermined analog input to be communicated to the analog physical object by means of signature device using the interactive system; 
 (e) the analog physical signature device being operative configured to transform the predetermined analog input to a consequent, dependent analog output that is causally related to a predefined digital output by means of using the interactive system; and 
 (f) the alternative code segment being operative configured to perform program functionality dependent upon the predetermined digital input and the predefined digital output. 
 
     
     
       2. The method of  claim 1  wherein the computer program implements the intended functionality after replacement of the code segment with the alternative code segment if and only if the computer program is bound to the analog physical signature device such that the alternative code segment is operative, using the predefined digital output causally related to operation of the bound analog physical signature device, to realize the functionality of the replaced code segment. 
     
     
       3. The method of  claim 1  wherein the computer program does not implement the intended functionality after replacement of the code segment with the alternative code segment if the computer program is bound to any other analog physical signature device since the alternative code segment is operative, using any other predefined digital output causally related to operation of any such other bound analog physical signature device, to realize functionality other than the functionality of the replaced code segment. 
     
     
       4. The method of  claim 1  wherein the predefined consequent, dependent analog output of the analog physical signature device to which the computer program is bound is unique among all similar analog physical signature devices for the predetermined analog input. 
     
     
       5. The method of  claim 1  wherein the interactive system includes a digital-to-analog conversion means that is operative to provide the causal relationship between the predetermined digital input and the predetermined analog input. 
     
     
       6. The method of  claim 1  wherein the interactive system includes an analog-to-digital conversion means that is operative to provide the causal relationship between the consequent, dependent analog output and the consequent, dependent digital output. 
     
     
       7. The method of  claim 1  wherein the replaced program expression is one of a program constant, a computational constant, a logical constant, a representational constant, a message constant, a program variable, an input variable, an intermediate result variable, a pointer variable, an output variable, a program function, an offset function, a size function, a format function, mathematical function, and a scientific function. 
     
     
       8. The method of  claim 7  wherein the replaced program constant is a computational constant. 
     
     
       9. The method of  claim 7  wherein the replaced program constant is a logical constant. 
     
     
       10. The method of  claim 7  wherein the replaced program constant is a representational constant. 
     
     
       11. The method of  claim 7  wherein the replaced program constant is a message constant. 
     
     
       12. The method of  claim 1  wherein the replaced program expression is a program variable. 
     
     
       13. The method of  claim 12  wherein the replaced program variable is an input variable. 
     
     
       14. The method of  claim 12  wherein the replaced program variable is an intermediate result variable. 
     
     
       15. The method of  claim 12  wherein the replaced program variable is a pointer variable. 
     
     
       16. The method of  claim 12  wherein the replaced program variable is an output variable. 
     
     
       17. The method of  claim 1  wherein the replaced program expression is a program function. 
     
     
       18. The method of  claim 17  wherein the replaced program function is an offset function. 
     
     
       19. The method of  claim 17  wherein the replaced program function is a size function. 
     
     
       20. The method of  claim 17  wherein the replaced program function is a format function. 
     
     
       21. The method of  claim 17  wherein the replaced program function is a mathematical or scientific function. 
     
     
       22. The method of  claim 1  wherein the bound analog physical signature device comprises a relatively complex, immutable, inhomogeneous material that is operative to transform radiant waves such that the predetermined analog input is a predetermined radiant wave and the consequent, dependent analog output is a consequent, dependent radiant wave. 
     
     
       23. The method of  claim 22  wherein the relatively complex, immutable, inhomogeneous material is operative to transform waves in the acoustic spectrum such that the predetermined analog input is a predetermined wave input in the acoustic spectrum and the consequent, dependent analog output is a consequent, dependent wave output in the acoustic spectrum. 
     
     
       24. The method of  claim 23  wherein the relatively complex, immutable, inhomogeneous material is a solid block. 
     
     
       25. The method of  claim 23  wherein the relatively complex, immutable, inhomogeneous material is a closed hollow container filled with a viscous fluid. 
     
     
       26. The method of  claim 23  wherein the relatively complex, immutable, inhomogeneous material is a disc of porous sintered metal. 
     
     
       27. The method of  claim 23  wherein the relatively complex, immutable, inhomogeneous material is a closed hollow container filled with ringing metal objects. 
     
     
       28. The method of  claim 23  wherein the relatively complex, immutable, inhomogeneous material comprises a membrane stretched over a rigid structure. 
     
     
       29. The method of  claim 22  wherein the relatively complex, immutable, inhomogeneous material is operative to transform waves in the electromagnetic spectrum such that the predetermined analog input is a predetermined wave input in the electromagnetic spectrum and the consequent, dependent analog output is a consequent, dependent wave output in the electromagnetic spectrum. 
     
     
       30. The method of  claim 29  wherein the relatively complex, immutable, inhomogeneous material that is operative to transform light waves such that the predetermined analog input is a predetermined light wave input and the consequent, dependent analog output is a consequent, dependent light wave output. 
     
     
       31. The method of  claim 30  wherein the relatively complex, immutable, inhomogeneous material is a solid translucent rod having small reflective flakes embedded therein. 
     
     
       32. The method of  claim 30  wherein the relatively complex, immutable, inhomogeneous material is a solid translucent rod having small translucent colored spheres embedded therein. 
     
     
       33. The method of  claim 30  wherein the relatively complex, immutable, inhomogeneous material is a glass mirror having impurities embedded therein. 
     
     
       34. The method of  claim 30  wherein the relatively complex, immutable, inhomogeneous material is a glass mirror having surface irregularities. 
     
     
       35. The method of  claim 30  wherein the relatively complex, immutable, inhomogeneous material is a glass mirror having an inhomogeneous metallic backing. 
     
     
       36. The method of  claim 1  wherein the replacing step comprises:
 replacing a plurality of code segments of the computer program instructions representing a corresponding plurality of program expressions with alternative code segments, each alternative code segment defining a predetermined digital input that is causally related to a predetermined analog input by the interactive system such that each of the alternative code segments is operative to perform program functionality dependent upon the predetermined digital input and the predefined digital output associated with each such alternative code segment. 
 
     
     
       37. An interactive system for binding a computer program, the computer program including instructions for implementing an intended functionality, the interactive system comprising:
 an analog physical signature device that is operative to transform an analog input into a consequent, dependent analog output; 
 an alternative code segment that replaces a code segment of the computer program instructions representing a program expression to bind the computer program to the analog physical signature device, the alternative code segment defining a predetermined digital input; 
 a digital-to-analog conversion means in communication with the computer program and the analog physical signature device and operative to causally relate the predetermined digital input to a predetermined analog input that is communicated to the analog physical signature device wherein the predetermined analog input is transformed into a consequent, dependent analog output; and 
 an analog-to-digital conversion means in communication with the computer program and the analog physical signature device and operative to causally relate the consequent, dependent analog output to a predefined digital output; 
 the alternative code segment including instructions for communicating the predetermined digital input to the digital-to-analog conversion means, for retrieving the predefined digital output from the analog-to-digital conversion means, and for functionally processing the predefined digital output; 
 wherein, when the alternative code segment is encountered during execution of the computer program instructions, the alternative code segment is operative to communicate the predetermined digital input to the digital-to-analog conversion means and to perform program functionality dependent upon the predetermined digital input and the predefined digital output retrieved from the analog-to-digital conversion means. 
 
     
     
       38. The interactive system of claim  1  37 wherein the analog physical signature device comprises:
 a relatively complex, immutable, inhomogeneous material that is operative to transform the predetermined analog input into the consequent, dependent analog output; 
 means in communication with the digital-to-analog conversion means and operative to interact the analog input with the relatively complex, immutable, inhomogeneous material; and 
 means for detecting the consequent, dependent analog output from the relatively complex, immutable, inhomogeneous material. 
 
     
     
       39. The interactive system of  claim 38  wherein the relatively complex, immutable, inhomogeneous material is operative to transform radiant waves such that the predetermined analog input is a predetermined radiant wave input and the consequent, dependent analog output is a consequent, dependent radiant wave output. 
     
     
       40. The interactive system of  claim 39  wherein the radiant waves are in the electromagnetic spectrum such that the predetermined radiant wave input is a predetermined wave input in the electromagnetic spectrum and the consequent, dependent wave output is a consequence, dependent wave output in the electromagnetic spectrum. 
     
     
       41. The interactive system of  claim 40  wherein the radiant waves in the electromagnetic spectrum are light waves such that the predetermined wave input in the electromagnetic spectrum is a predetermined light wave input and the consequent, dependent wave output in the electromagnetic spectrum is a consequent, dependent light wave output. 
     
     
       42. The interactive system of  claim 41  wherein the relatively complex, immutable, inhomogeneous material is a solid translucent rod having small reflective flakes embedded therein that is operative to transform the predetermined light wave input into the consequent dependent light wave output. 
     
     
       43. The interactive system of  claim 41  wherein the relatively complex, immutable, inhomogeneous material is a solid translucent rod having small translucent colored spheres embedded therein that is operative to transform the predetermined light wave input into the consequent dependent light wave output. 
     
     
       44. The interactive system of  claim 41  wherein the relatively complex, immutable, inhomogeneous material is a glass mirror having impurities embedded therein that is operative to transform the predetermined light wave input into the consequent dependent light wave output. 
     
     
       45. The interactive system of  claim 41  wherein the relatively complex, immutable, inhomogeneous material is a glass mirror having surface irregularities that is operative to transform the predetermined light wave input into the consequent dependent light wave output. 
     
     
       46. The interactive system of  claim 41  wherein the relatively complex, immutable, inhomogeneous material is a glass mirror having an inhomogeneous metallic backing that is operative to transform the predetermined light wave input into the consequent dependent wave output that is operative to transform the predetermined light wave input into the consequent dependent light wave output. 
     
     
       47. The interactive system of  claim 39  wherein the radiant waves are in the acoustic spectrum such that the predetermined radiant wave input is a predetermined acoustic wave input and the consequent, dependent wave output is a consequent, dependent acoustic wave output. 
     
     
       48. The interactive system of  claim 47  wherein the relatively complex, immutable, inhomogeneous material is a solid block that is operative to transform the predetermined acoustic wave input to the consequent, dependent acoustic wave output. 
     
     
       49. The interactive system of  claim 47  wherein the relatively complex, immutable, inhomogeneous material is a closed hollow container filled with a viscous fluid that is operative to transform the predetermined acoustic wave input to the consequent, dependent acoustic wave output. 
     
     
       50. The interactive system of  claim 47  wherein the relatively complex, immutable, inhomogeneous material is a disc of porous sintered metal that is operative to transform the predetermined acoustic wave input to the consequent, dependent acoustic wave output. 
     
     
       51. The interactive system of  claim 47  wherein the relatively complex, immutable, inhomogeneous material is a closed hollow container filled with ringing metal objects that is operative to transform the predetermined acoustic wave input to the consequent, dependent acoustic wave output. 
     
     
       52. The interactive system of  claim 47  wherein the relatively complex, immutable, inhomogeneous material comprises a membrane stretched over a rigid structure that is operative to transform the predetermined acoustic wave input to the consequent, dependent acoustic wave output. 
     
     
       53. The interactive system of  claim 37  wherein the replaced program expression is one of a program constant, a computational constant, a logical constant, a representational constant, a message constant, a program variable, an input variable, an intermediate result variable, a pointer variable, an output variable, a program function, an offset function, a size function, a format function, a mathematical function, and a scientific function. 
     
     
       54. The interactive system of  claim 53  wherein the replaced program constant is a computational constant. 
     
     
       55. The interactive system of  claim 53  wherein the replaced program constant is a logical constant. 
     
     
       56. The interactive system of  claim 53  wherein the replaced program constant is a representational constant. 
     
     
       57. The interactive system of  claim 53  wherein the replaced program constant is a message constant. 
     
     
       58. The interactive system of  claim 37  wherein the replaced program expression is a program variable. 
     
     
       59. The interactive system of  claim 58  wherein the replaced program variable is an input variable. 
     
     
       60. The interactive system of  claim 58  wherein the replaced program variable is an intermediate result variable. 
     
     
       61. The interactive system of  claim 58  wherein the replaced program variable is a pointer variable. 
     
     
       62. The interactive system of  claim 58  wherein the replaced program variable is an output variable. 
     
     
       63. The interactive system of  claim 37  wherein the replaced program expression is a program function. 
     
     
       64. The interactive system of  claim 63  wherein the replaced program function is an offset function. 
     
     
       65. The interactive system of  claim 63  wherein the replaced program function is a size function. 
     
     
       66. The interactive system of  claim 63  wherein the replaced program function is a format function. 
     
     
       67. The interactive system of  claim 63  wherein the replaced program function is a mathematical or scientific function. 
     
     
       68. The interactive system of  claim 37  wherein the computer program implements the intended functionality after replacement of the code segment with the alternative code segment if and only if the computer program is bound to the analog physical signature device, such that the alternative code segment is operative, using the predefined digital output causally related to operation of the analog physical signature device, to realize the functionality of the replaced code segment. 
     
     
       69. The interactive system of  claim 37  wherein the computer program does not implement the intended functionality after replacement of the one code segment with the alternative code segment if the computer program is bound to any other analog physical signature device since the alternative code segment is operative, using any other predefined digital output causally related to operation of any other bound analog physical signature device, to realize functionality other than the functionality of the replaced code segment. 
     
     
       70. The interactive system of  claim 37  wherein the replaced program expression and the operation of the analog physical signature device in combination provide protection against reverse engineering of the bound computer program. 
     
     
       71. The method of  claim 1  wherein the replaced program expression and the operation of the analog physical signature device in combination provide protection against reverse engineering of the bound computer program. 
     
     
       72. A method for binding a computer program to an analog physical signature device comprising:
 executing a code segment, the code segment defining a predetermined digital input for transformation by an analog physical signature device;   converting the digital input to an associated analog input;   communicating the associated analog input to the analog physical signature device;   the analog physical signature device transforming the associated analog input to a consequent, dependent analog output different from the input;   converting the analog output to an associated digital output; and   returning the associated digital output to the code segment, the code segment being operative to perform program functionality dependent upon the associated digital output.   
     
     
       73. The method of claim 72, wherein the associated digital output is used in the code segment as one of a program constant, a computational constant, a logical constant, a representational constant, a message constant, a program variable, an input variable, an intermediate result variable, a pointer variable, an output variable, a program function, an offset function, a size function, a format function, a mathematical function, and a scientific function. 
     
     
       74. The method of claim 72, wherein the analog physical signature device comprises an immutable, inhomogeneous material that is operative to transform an input radiant wave to a corresponding output radiant wave different from the input radiant wave. 
     
     
       75. The method of claim 74, wherein the radiant wave is a sonic wave. 
     
     
       76. The method of claim 74, wherein the radiant wave is a light wave. 
     
     
       77. The method of claim 72, wherein the code segment is configured to perform an intended function only upon reception of the associated digital output that has been properly transformed by the analog physical signature device. 
     
     
       78. The method of claim 72, wherein the code segment is configured to perform an incorrect function upon reception of the associated digital output that has not been properly transformed by the analog physical signature device. 
     
     
       79. An interactive system for binding a computer program comprising:
 a first code segment defining a predetermined digital input;   a digital-to-analog conversion circuit configured to convert the predetermined digital input to a corresponding analog input and to communicate the analog input;   an analog physical signature device configured to transform the analog input into a consequent, dependent analog output different from the analog input;   an analog-to-digital conversion circuit configured to convert the consequent, dependent analog output of the analog physical signature device to a predefined digital output; and   a second code segment configured to perform program functionality dependent upon the predefined digital output.   
     
     
       80. The interactive system of claim 79, wherein the second code segment is configured to use the predefined digital output as one of a program constant, a computational constant, a logical constant a representational constant, a message constant, a program variable, an input variable, an intermediate result variable, a pointer variable, an output variable, a program function, an offset function, a size function, a format function, a mathematical function, and a scientific function. 
     
     
       81. The interactive system of claim 79, wherein the analog physical signature device comprises an immutable, inhomogeneous material that is operative to transform an input radiant wave to a corresponding output radiant wave different from the input radiant wave. 
     
     
       82. The interactive system of claim 81, wherein the input radiant wave is a sonic wave. 
     
     
       83. The interactive system of claim 81, wherein the input radiant wave is a light wave. 
     
     
       84. The interactive system of claim 79, wherein the second code segment is configured to perform an intended function only upon reception of the associated digital output that has been properly transformed by the analog physical signature device. 
     
     
       85. The interactive system of claim 79, wherein the second code segment is configured to perform an incorrect function upon reception of the associated digital output that has not been properly transformed by the analog physical signature device. 
     
     
       86. An interactive system for binding a computer program comprising:
 first code segment means for defining a predetermined digital input;   digital-to-analog conversion means for converting the predetermined digital input to a corresponding analog input;   analog physical signature means for transforming the corresponding analog input into a consequent, dependent analog output different from the corresponding analog input;   analog-to-digital conversion means for converting the consequent, dependent analog output of the analog physical signature means to a predefined digital output; and   second code segment means for performing program functionality dependent upon the predefined digital output.   
     
     
       87. The interactive system of claim 86, wherein the second code segment means is configured to use the predefined digital output as one of a program constant, a computational constant, a logical constant, a representational constant, a message constant, a program variable, an input variable, an intermediate result variable, a pointer variable, an output variable, a program function, an offset function, a size function, a format function, a mathematical function, and a scientific function. 
     
     
       88. The interactive system of claim 86, wherein the analog physical signature means comprises an immutable, inhomogeneous material that is operative to transform an input radiant wave to a corresponding output radiant wave different from the input radiant wave. 
     
     
       89. The interactive system of claim 88, wherein the input radiant wave is a sonic wave. 
     
     
       90. The interactive system of claim 88, wherein the input radiant wave is a light wave. 
     
     
       91. The interactive system of claim 86, wherein the second code segment means is configured to perform an intended function only upon reception of the predefined digital output that has been properly transformed by the analog physical signature means. 
     
     
       92. The interactive system of claim 86, wherein the second code segment means is configured to perform an incorrect function upon reception of the predefined digital output that has not been properly transformed by the analog physical signature means. 
     
     
       93. An analog physical signature transformation device for preventing unauthorized modification and duplication of software code on a computing device, the analog physical signature transformation device comprising:
 an input configured to interface with the computing device;   an output configured to interface with the computing device; and   an immutable, inhomogeneous material coupled between the input and the output and configured to transform an input radiant wave received at the input to a corresponding output radiant wave at the output different from the input radiant wave;   wherein the input radiant wave is one selected from the group consisting of a light wave and a sonic wave; and   wherein the immutable, inhomogeneous material comprises at least one of:
 a membrane stretched over a rigid structure; 
 a closed partially hollow container filled with a viscous fluid; 
 a closed hollow container filled with ringing metal objects; 
 a glass mirror having impurities embedded therein; 
 a glass mirror having surface irregularities; and 
 a glass mirror having an inhomogeneous metallic backing. 
   
     
     
       94. The analog physical signature transformation device of claim 93, wherein the immutable, inhomogeneous material is one of (i) a solid block and (ii) a membrane stretched over a rigid structure. 
     
     
       95. The analog physical signature transformation device of claim 93, wherein the immutable, inhomogeneous material is one of (i) a closed partially hollow container filled with a viscous fluid, (ii) a closed hollow container filled with ringing metal objects, and (iii) a disc of porous sintered metal. 
     
     
       96. The analog physical signature transformation device of claim 93, wherein the immutable, inhomogeneous material further comprises one of (i) a solid translucent rod having small reflective flakes embedded therein and (ii) a solid translucent rod having small translucent colored spheres embedded therein. 
     
     
       97. The analog physical signature transformation device of claim 93, wherein the immutable, inhomogeneous material is one of (i) a glass mirror having impurities embedded therein, (ii) a glass mirror having surface irregularities, and (iii) a glass mirror having an inhomogeneous metallic backing. 
     
     
       98. An analog physical signature transformation device for preventing unauthorized modification and duplication of software code on a computing device, the analog physical signature transformation device comprising:
 input means for interfacing with the computing device;   output means for interfacing with the computing device; and   transformation means for transforming an input radiant wave received at the input means to a corresponding output radiant wave at the output means different from the input radiant wave, wherein the transformation means include an immutable, inhomogeneous material coupled between the input means and the output means;   wherein the input radiant wave is one selected from the group consisting of a light wave and a sonic wave; and   wherein the immutable, inhomogeneous material comprises at least one of:
 a membrane stretched over a rigid structure; 
 a closed partially hollow container filled with a viscous fluid; 
 a closed hollow container filled with ringing metal objects; 
 a glass mirror having impurities embedded therein; 
 a glass mirror having surface irregularities; and 
 a glass mirror having an inhomogeneous metallic backing. 
   
     
     
       99. The analog physical signature transformation device of claim 98, wherein the immutable, inhomogeneous material is one of (i) a solid block and (ii) a membrane stretched over a rigid structure. 
     
     
       100. The analog physical signature transformation device of claim 98, wherein the immutable, inhomogeneous material is one of (i) a closed partially hollow container filled with a viscous fluid, (ii) a closed hollow container filled with ringing metal objects, and (iii) a disc of porous sintered metal. 
     
     
       101. The analog physical signature transformation device of claim 98, wherein the immutable, inhomogeneous material further comprises one of (i) a solid translucent rod having small reflective flakes embedded therein and (ii) a solid translucent rod having small translucent colored spheres embedded therein. 
     
     
       102. The analog physical signature transformation device of claim 98, wherein the immutable, inhomogeneous material is one of (i) a glass mirror having impurities embedded therein, (ii) a glass mirror having surface irregularities, and (iii) a glass mirror having an inhomogeneous metallic backing. 
     
     
       103. A method for preventing unauthorized modification and duplication of software code on a computing device comprising:
 receiving a digital input from a computing device;   converting the digital input to an analog input signal selected from the group consisting of a light wave and a sonic wave;   transmitting the analog input signal across an immutable, inhomogeneous material configured to transform the analog input signal to a corresponding analog output signal different from the analog input signal;   converting the analog output signal to a digital output signal; and   transmitting the digital output signal to the computing device.   
     
     
       104. The method of claim 103, wherein the immutable, inhomogeneous material is one of (i) a solid block and (ii) a membrane stretched over a rigid structure. 
     
     
       105. The method of claim 103, wherein the immutable, inhomogeneous material is one of (i) a closed partially hollow container filled with a viscous fluid, (ii) a closed hollow container filled with ringing metal objects, and (iii) a disc of porous sintered metal. 
     
     
       106. The method of claim 103, wherein the immutable, inhomogeneous material is one of (i) a solid translucent rod having small reflective flakes embedded therein and (ii) a solid translucent rod having small translucent colored spheres embedded therein. 
     
     
       107. The method of claim 103, wherein the immutable, inhomogeneous material is one of (i) a glass mirror having impurities embedded therein, (ii) a glass mirror having surface irregularities, and (iii) a glass mirror having an inhomogeneous metallic backing.

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