Attestation using both fixed token and portable token
First Claim
1. A method comprisingrequesting a fixed token to create a sealed key blob comprising both a first key pair and first usage authorization data, wherein knowledge of the first usage authorization data is required in order to use a private key of the first key pair, andrequesting a portable token to create a protected key blob, where the protected key blob comprises the sealed key blob and second usage authorization data, wherein knowledge of the second usage authorization data is required in order to obtain the sealed key blob from the protected key blob.
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Accused Products
Abstract
Methods, apparatus and machine readable medium are described for creating and using protected key blobs that require a particular portable token be present before use of the key or keys of the protected key blob is granted. Such protected key blobs may be used to establish a level of trust between a local user and the computing device.
242 Citations
22 Claims
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1. A method comprising
requesting a fixed token to create a sealed key blob comprising both a first key pair and first usage authorization data, wherein knowledge of the first usage authorization data is required in order to use a private key of the first key pair, and requesting a portable token to create a protected key blob, where the protected key blob comprises the sealed key blob and second usage authorization data, wherein knowledge of the second usage authorization data is required in order to obtain the sealed key blob from the protected key blob.
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14. A computing device, comprising
a fixed token comprising a first processing unit and first protected storage, the first processing unit to load a first key pair of a sealed key blob into the first protected storage in response to determining that a first authentication code has a predetermined relationship to first usage authorization data of the sealed key blob, a portable token comprising a second processing unit and second protected storage, the second processing unit to return the sealed key blob from a protected key blob in response to determining that a second authentication code has a predetermined relationship to second usage authorization data of the protected key blob, a portable token interface that enables the portable token to be coupled to and removed from the computing device, a processor to provide the portable token with a request for the sealed key blob, wherein the request that comprises the protected key blob and the second authentication code, and to provide the fixed token with a request to load the first key pair, wherein the request comprises the sealed key blob and the first authentication code.
Specification