Methods and apparatus for securely enabling features in highly integrated electronic circuits
First Claim
1. A computer security system to prevent unauthorized use of high level integrated optional features in an integrated circuit arrangement having a control unit, said security system comprising:
- a first level of security for securely determining whether said optional features are to be enabled, comprising;
means for generating a multiplicity of unencrypted question values and encrypted answer values;
key means coupled to receive said unencrypted question values for generating a multiplicity of encrypted key values;
comparison means coupled to receive, respectively, said encrypted answer and encrypted key values;
and if said encrypted key values match said encrypted answer values, said comparison means signaling said control unit that said key means is authentic and that said high level integrated optional features are to be enabled, and;
a second level of security comprising means for securing said first level of security.
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Abstract
Methods and apparatus for securely providing an encryption scheme for a highly integrated circuit arrangement using external function-enabling keys. Unencrypted question and encrypted expected answer values are stored in question and answer registers respectively. The encrypted expected answer value is derived from a suitably secure encryption scheme. An external key chip incorporating a coding block implementing the identical encryption scheme is provided for each optional feature to be enabled. The unencrypted question value is routed to the input of the coding block. The coding block returns an encrypted key answer value to a comparator in the circuit arrangement. The encrypted key answer value is compared to the encrypted expected answer value stored in the answer register and, if equivalent, the comparator signals the circuit arrangement that a match has been found and that the optional function is to be enabled. The unencrypted questions values together with the associated expected answer values may be randomized according to any suitable randomization scheme. Determination of the expected answer values to circumvent the security feature in commercially viable quantities is greatly reduced.
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Citations
46 Claims
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1. A computer security system to prevent unauthorized use of high level integrated optional features in an integrated circuit arrangement having a control unit, said security system comprising:
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a first level of security for securely determining whether said optional features are to be enabled, comprising; means for generating a multiplicity of unencrypted question values and encrypted answer values; key means coupled to receive said unencrypted question values for generating a multiplicity of encrypted key values; comparison means coupled to receive, respectively, said encrypted answer and encrypted key values; and if said encrypted key values match said encrypted answer values, said comparison means signaling said control unit that said key means is authentic and that said high level integrated optional features are to be enabled, and; a second level of security comprising means for securing said first level of security. - View Dependent Claims (2, 3, 4, 5)
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6. In a computer security system comprising high level integrated optional features in an integrated circuit arrangement having a control unit, a method to prevent unauthorized use of high level integrated optional features comprising the steps of;
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providing a first level of security for securely determining whether said optional features are to be enabled comprising the steps of; generating a multiplicity of unencrypted question values and encrypted answer values; providing key means coupled to receive said unencrypted question values for generating a multiplicity of encrypted key values; providing comparison means coupled to receive, respectively, said encrypted answer and encrypted key values; and if said encrypted key values match said encrypted answer values, signaling said control unit that said key means is authentic and that said high level integrated optional features are to be enabled, and; providing a second level of security for securing said first level of security. - View Dependent Claims (7, 8, 9, 10)
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11. In an integrated computer processor system including a control unit, memory, and at least one high level integrated optional feature, a security system comprising:
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question value means for generating a multiplicity of question values; a key device coupled to receive said question values from said question value means, said key device transforming said question values to a multiplicity of key answer values; answer value means for generating a multiplicity of expected answer values; and
,comparison means coupled to said key device and said answer value means for receiving, respectively, said key answer values and said expected answer values; if said key answer values match said expected answer values, said comparison means signalling said CPU that said key device is authentic and that said high level integrated optional features are to be enabled. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 23, 24, 25)
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26. In an integrated computer processor system including a central processing unit (CPU), memory, and at least one high level integrated optional feature, a security system comprising:
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a first storage means for storing an encoded question value; a key device coupled to receive said encoded question value from said first storage means, said key device transforming said encoded question value to a key answer value; a second storage means for storing an expected answer value; and
,a comparator coupled to receive said key answer value and said expected answer value, and if said key answer values match said expected answer values, said comparator signalling said CPU that said key chip is authentic, said CPU thereafter enabling said high level optional integrated feature. - View Dependent Claims (21, 22, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. In an integrated computer processor system including a control unit, memory, and at least one high level integrated optional feature, a security method for preventing unauthorized use of said high level integrated optional features, said security method comprising the steps of:
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generating a multiplicity of question values; providing a key device to transform said question values into a plurality of key answer values; generating a plurality of expected answer values; and
,comparing said key answer values and said expected answer values in a comparison means; if said key answer values match said expected answer values;
signalling said control unit that said key device is authentic and that said high level integrated optional features are to be enabled. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43, 44, 45, 46)
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Specification