Cryptographic security module method and apparatus
First Claim
1. A cryptographic security module, in which a private part of a cryptographic key is held and from which a public part of the cryptographic key can be extracted, and in which the module can generate a new key, the private part of the cryptographic key being usable to generate a key-generation certificate by signing, either directly or indirectly through one or more levels of indirection, a key-generation message containing information by which the new key can be identified.
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Abstract
A cryptographic security module holds a cryptographic key having a private part and a public part. The private part is held within the module and is usable only to sign messages generated within the module. The public part can be extracted from the module and is usable by a warranting authority to generate a warrant for the module. The module may be used to generate a new key and the private part of the cryptographic key used to generate a key-generation certificate by signing a key-generation message containing information by which the new key can be identified.
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Citations
33 Claims
- 1. A cryptographic security module, in which a private part of a cryptographic key is held and from which a public part of the cryptographic key can be extracted, and in which the module can generate a new key, the private part of the cryptographic key being usable to generate a key-generation certificate by signing, either directly or indirectly through one or more levels of indirection, a key-generation message containing information by which the new key can be identified.
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8. A method for operating a security module, comprising the steps of;
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holding a private part of a cryptographic key in the module;
using the module to generate a new key;
generating a key-generation message pertaining to the generation of the new key; and
generating a key-generation certificate by using the private part of the cryptographic key to sign the key-generation message, either directly or indirectly through one or more levels of indirection. - View Dependent Claims (9, 10, 11)
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12. A method for warranting a cryptographic security module, comprising the steps of;
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ascertaining that the module holds a warrantable key, comprising a private part held within the module and only usable to sign messages generated within the module, and a public part which is extractable from the module;
generating a warrant message identifying the public part of the warrantable key and the module; and
signing the warrant message using a private part of a warranting key to generate a warrant. - View Dependent Claims (13, 14, 15, 16)
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17. A method for verifying that a cryptographic key has been generated by a predetermined cryptographic security module, being either a specific, identifiable module or a module of a predetermined type or complying with a predetermined standard, comprising the steps of;
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receiving a key-generation certificate purportedly (i) generated in the predetermined module, (ii) containing information from which the key can be identified and (iii) signed by a private part of a warrantable key held in the predetermined module;
receiving a warrant identifying a public part of a warranted key and warranting that it was extracted from a module which has been inspected by a warranting authority; and
verifying that the public part of the warranted key validates the key-generation certificate. - View Dependent Claims (18, 19, 20, 21, 22)
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23. A method for verifying the origin of a cryptographic key purportedly generated by a predetermined cryptographic security module, comprising the steps of;
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receiving a certificate certifying that the key was generated by the module, the certificate having been generated by the following steps;
inspecting the module and ascertaining that it holds a warrantable key, comprising a private part held within the module and only usable to sign messages generated within the module, and a public part which is extractable from the module;
generating a warrant message identifying the public part of the warrantable key and the module;
signing the warrant message using a private part of a warranting key to generate a warrant;
receiving a key-generation certificate generated in the module, containing information from which the key can be identified and signed by the private part of the warrantable key;
receiving the warrant identifying the public part of the warrantable key and warranting that it was extracted from the module after inspection by a warranting authority;
verifying that a public part of the warranting key validates the warrant;
verifying that the public part of the warrantable key validates the key-generation certificate; and
issuing the certificate.
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- 24. A cryptographic security module, in which a private part of a warrantable key is held and from which a public part of the warrantable key can be extracted, the private part being usable only to sign messages generated within the module and the public part being usable by a warranting authority to generate a warrant.
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26. A method for operating a security module, comprising the steps of;
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holding a private part of a warrantable key in the module, the private part being usable only to sign messages generated within the module;
extracting a public part of the warrantable key from the module; and
generating a warrant as evidence that the module contains the warrantable key. - View Dependent Claims (27)
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28. A cryptographic security module comprising:
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a first memory region that stores a private part of a cryptographic key;
a second memory region that stores a public part of the cryptographic key;
logic that generates a new key, the private part of the cryptographic key being usable to generate a key-generation certificate by signing, either directly or indirectly through one or more levels of indirection, a key-generation message containing information by which the new key can be identified. - View Dependent Claims (29, 30, 31, 32, 33)
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Specification