Microsoft Corporation
Cryptographic hardware watchdog

Abstract:

A computing device's trusted platform module (TPM) is configured with a cryptographic watchdog timer which forces a device reset if the TPM fails to solve a cryptographic challenge before the expiration of the timer. The computing device's TPM is configured to generate the cryptographic challenge, to which the computing device does not possess the cryptographic token for resolution. While the watchdog timer counts down, the computing device requests a cryptographic token from a remote service to solve the challenge. The remote service transmits the cryptographic token to the computing device so long as the remote service identifies no reason to withhold the token, such as the computing device being infected with malware. The interoperability of the computing device and remote service enables the remote service to exercise control and reset capabilities over the computing device.