Microsoft Technology Licensing, LLC

Jeremiah J Cox

Alastair Wolman

Stefan Thom

Stefan Saroiu

Himanshu Raj

David John Linsley

David Michael Robinson

Magnus Nystrom

Rob Spiger

Alain L Michaud

Robert D Young

Ronald Aigner

Jonathan Bret Barkelew

A device includes a reset resistant store and a trusted key service. The reset resistant store maintains data across various different device reset or data invalidation operations. The trusted key service maintains, for each of one or more operating systems that run on the device from a boot configuration, an encrypted key associated with the boot configuration. The device also has a master key that is specific to the device. Each of the keys associated with a boot configuration is encrypted using the master key. When booting the device, the boot configuration being run on the device is identified, and the key associated with that boot configuration is obtained (e.g., from the reset resistant store or the encrypted key vault). The master key is used to decrypt the obtained key, and the obtained key is used to decrypt secrets associated with the operating system run from the boot configuration.

Maintaining operating system secrets across resets

A 'Firmware-Based TPM' or 'fTPM' ensures that secure code execution is isolated to prevent a wide variety of potential security breaches. Unlike a conventional hardware based Trusted Platform Module (TPM), isolation is achieved without the use of dedicated security processor hardware or silicon. In general, the fTPM is first instantiated in a pre-OS boot environment by reading the fTPM from system firmware or firmware accessible memory or storage and placed into read-only protected memory of the device. Once instantiated, the fTPM enables execution isolation for ensuring secure code execution. More specifically, the fTPM is placed into protected read-only memory to enable the device to use hardware such as the ARM&#xae; architecture's TrustZone&#x2122; extensions and security primitives (or similar processor architectures), and thus the devices based on such architectures, to provide secure execution isolation within a &#x201c;firmware-based TPM&#x201d; without requiring hardware modifications to existing devices.

Trustzone-based integrity measurements and verification using a software-based trusted platform module

Software-based trusted platform module

Firmware-based trusted platform module for arm processor architectures and trustzone security extensions

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Redmond, WA, United States of America

Jeremiah J Cox