JTAG fuse vulnerability determination and protection using a trusted execution environment

  • US 9,021,585 B1
  • Filed: 03/15/2013
  • Issued: 04/28/2015
  • Est. Priority Date: 03/15/2013
  • Status: Active Grant
First Claim
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1. A method of configuring a trusted security zone into a portable electronic device, comprising:

  • executing instructions on a processor of the portable electronic device that determine the state of a Joint Test Action Group (JTAG) port of the portable electronic device;

    responsive to a determination that the JTAG port is enabled, executing instructions on the processor preventing configuration of the trusted security zone into the portable electronic device;

    responsive to a determination that the JTAG port is disabled, configuring the trusted security zone into the portable electronic device, wherein the trusted security zone provides hardware assisted trust, wherein configuring the trusted security zone comprises installing the trusted security zone in a secure portion of a memory in the portable electronic device; and

    after the trusted security zone is configured into the portable electronic device, executing instructions on the processor creating a JTAG port inspected certificate and storing the JTAG port inspected certificate into a trusted memory area of the trusted security zone,wherein executing instructions on the processor preventing configuration of the trusted security zone into the portable electronic device responsive to the determination that the JTAG port is enabled reduces a vulnerability to hacking the trusted security zone via the enabled JTAG port.

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