Apparatus and method for managing a microprocessor providing for a secure execution mode
First Claim
1. An apparatus providing for a secure execution environment, comprising:
- an x86-compatible microprocessor, comprising;
one or more execution units, configured to execute non-secure application programs and a secure application program, wherein said non-secure application programs are accessed from a system memory via a system bus, and wherein said secure application program is executed in a secure execution mode;
a cryptographic unit;
a processor key register, coupled to said cryptographic unit, configured to store a cryptographic key that is unique to said x86-compatible microprocessor, wherein said cryptographic key is employed to encrypt said secure application program for storage, and wherein said processor key register can only be read by said cryptographic unit; and
secure execution mode logic, configured to monitor conditions corresponding to said x86-compatible microprocessor that are associated with potential security exposure and tampering, and configured to cause said x86-compatible microprocessor to transition to a degraded operating mode from said secure execution mode following detection of a first one or more of said conditions, wherein said degraded operating mode exclusively provides for execution of BIOS instructions, said BIOS instructions comprising instructions to allow for user input and display of messages; and
a secure non-volatile memory, coupled to said x86-compatible microprocessor via a private bus, configured to store said secure application program, wherein said secure application program is encrypted in said system memory according to an asymmetric cryptographic algorithm, and wherein, upon enablement of said secure execution mode, said microprocessor encrypts said secure application program according to a symmetric key algorithm and transfers said secure application program to said secure non-volatile memory over said private bus.
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Abstract
An apparatus providing for a secure execution environment including a microprocessor and a secure non-volatile memory. The microprocessor executes non-secure application programs and a secure application program. The non-secure application programs are accessed from a system memory via a system bus. The secure application program executes in a secure execution mode. The microprocessor has secure execution mode logic that monitors conditions corresponding to the microprocessor associated with tampering, and causes the microprocessor to transition to a degraded operating mode from the secure execution mode following detection of a first one or more of the conditions. The degraded operating mode exclusively provides for execution of BIOS instructions. The secure non-volatile memory is coupled to the microprocessor via a private bus, stores the secure application program. Transactions over the private bus are isolated from the system bus and corresponding system bus resources within the microprocessor.
169 Citations
24 Claims
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1. An apparatus providing for a secure execution environment, comprising:
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an x86-compatible microprocessor, comprising; one or more execution units, configured to execute non-secure application programs and a secure application program, wherein said non-secure application programs are accessed from a system memory via a system bus, and wherein said secure application program is executed in a secure execution mode; a cryptographic unit; a processor key register, coupled to said cryptographic unit, configured to store a cryptographic key that is unique to said x86-compatible microprocessor, wherein said cryptographic key is employed to encrypt said secure application program for storage, and wherein said processor key register can only be read by said cryptographic unit; and secure execution mode logic, configured to monitor conditions corresponding to said x86-compatible microprocessor that are associated with potential security exposure and tampering, and configured to cause said x86-compatible microprocessor to transition to a degraded operating mode from said secure execution mode following detection of a first one or more of said conditions, wherein said degraded operating mode exclusively provides for execution of BIOS instructions, said BIOS instructions comprising instructions to allow for user input and display of messages; and a secure non-volatile memory, coupled to said x86-compatible microprocessor via a private bus, configured to store said secure application program, wherein said secure application program is encrypted in said system memory according to an asymmetric cryptographic algorithm, and wherein, upon enablement of said secure execution mode, said microprocessor encrypts said secure application program according to a symmetric key algorithm and transfers said secure application program to said secure non-volatile memory over said private bus. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A microprocessor apparatus, for executing secure code within a secure execution environment, the microprocessor apparatus comprising:
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a secure non-volatile memory, configured to store a secure application program, wherein said secure application program is encrypted in a system memory according to an asymmetric cryptographic algorithm, and wherein said secure application program is retrieved from said system memory and is encrypted using a cryptographic key, and transferred over a private bus to said secure non-volatile memory; and an x86-compatible microprocessor, coupled to said secure non-volatile memory via said private bus, said x86-compatible microprocessor comprising; one or more execution units, configured to execute non-secure application programs and said secure application program; a cryptographic unit; a processor key register, coupled to said cryptographic unit, configured to store said cryptographic key, wherein said cryptographic key is unique to said x86-compatible microprocessor, wherein said cryptographic key is employed to encrypt said secure application program for storage into said secure non-volatile memory, and wherein said processor key register can only be read by said cryptographic unit; and secure execution mode logic, configured to monitor conditions corresponding to said x86-compatible microprocessor that are associated with potential security exposure and tampering, and configured to cause said x86-compatible microprocessor to transition to a degraded operating mode from said secure execution mode following detection of a first one or more of said conditions, wherein said degraded operating mode exclusively provides for execution of BIOS instructions, said BIOS instructions comprising instructions to allow for user input and display of messages. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method for executing secure code within a secure execution environment, the method comprising:
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accessing the secure code in a system memory, wherein the secure code is encrypted according to an asymmetric cryptographic algorithm; via a cryptographic unit disposed within an x86-compatible microprocessor, encrypting the secure code using a cryptographic key, and transferring the secure code over a private bus to a secure non-volatile memory for storage of the secure code, said encrypting comprising; first accessing a processor key register, coupled to the cryptographic unit, configured to store a cryptographic key that is unique to the x86-compatible microprocessor, wherein the cryptographic key is programmed into the processor key register during fabrication of the x86-compatible microprocessor, and wherein the processor key register can only be read by the cryptographic unit; and
;second accessing the secure code within the secure non-volatile memory via private transactions accomplished over a private bus that is coupled between the secure non-volatile memory and the x86-compatible microprocessor, wherein the private bus is isolated from all system bus resources within the x86-compatible microprocessor and external to the x86-compatible microprocessor, and wherein the private bus is observable and accessible exclusively by secure execution logic within the x86-compatible microprocessor; employing one or more execution units disposed within the x86-compatible microprocessor to execute the secure code; monitoring conditions corresponding to the x86-compatible microprocessor that are associated with potential security exposure and tampering; and first transitioning the x86-compatible microprocessor to a degraded operating mode from the secure execution mode following detection of a first one or more of the conditions, wherein the degraded operating mode exclusively provides for execution of BIOS instructions, the BIOS instructions comprising instructions to allow for user input and display of messages. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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Specification