Apparatus and method for protecting diagnostic ports of secure devices
First Claim
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1. An electronic system comprising:
- a processor;
a diagnostic port;
a switching circuit, including a switch connected between the diagnostic port and the processor, for enabling and disabling the diagnostic port and for restricting access to contents of the electronic system prior to enabling the diagnostic port;
a hardware sensor circuit for detecting if a connector is attached to the diagnostic port and for activating the switching circuit if the connector is detected; and
a secret root key stored in a non-volatile memory for encrypting and decrypting data in the electronic system, wherein the switching circuit restricts access to contents of the electronic system by masking the secret root key such that attempted access to the secret root key results in a predetermined value, and wherein the switching circuit resets the system before the switch is closed.
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Abstract
An electronic system comprises a processor, a diagnostic port, and a switching circuit, including a switch connected between the diagnostic port and the processor, for enabling and disabling the diagnostic port and for restricting access to contents of the electronic system prior to enabling the diagnostic port. A method for operating the electronic system is also included.
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Citations
13 Claims
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1. An electronic system comprising:
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a processor; a diagnostic port; a switching circuit, including a switch connected between the diagnostic port and the processor, for enabling and disabling the diagnostic port and for restricting access to contents of the electronic system prior to enabling the diagnostic port; a hardware sensor circuit for detecting if a connector is attached to the diagnostic port and for activating the switching circuit if the connector is detected; and a secret root key stored in a non-volatile memory for encrypting and decrypting data in the electronic system, wherein the switching circuit restricts access to contents of the electronic system by masking the secret root key such that attempted access to the secret root key results in a predetermined value, and wherein the switching circuit resets the system before the switch is closed. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of operating an electronic system, the method comprising:
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providing a switching circuit, including a switch connected between a diagnostic port and a processor for enabling and disabling the diagnostic port; determining the operational status of the switch; using a hardware sensing circuit to detect if a connector is attached to the diagnostic port and to activate the switching circuit if the connector is detected; and using the switching circuit to restrict access to contents of the electronic system in response to the operational status of the switch prior to enabling the diagnostic port, wherein the switching circuit restricts access to contents of the electronic system by masking a secret root key such that attempted access to the secret root key results in a predetermined value, and wherein the switching circuit resets the system before the switch is closed. - View Dependent Claims (9, 10, 11, 12, 13)
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Specification