Patent attributes
A health ticket minting process operates in a secure enclave on a computing device to ensure liveness of the enclave should a maliciously-compromised operating system deny service to starve the enclave. Cryptographically-secured health tickets provided by the minting process reset an authenticated watchdog timer (AWDT) that reboots the device from a hardware-protected recovery operating system if the timer expires. The health tickets are written to a secure channel using a symmetric key that is provisioned by repurposing an existing Intel SGX (Software Guard Extension) Versioning Support protocol that enables migration of secrets between enclaves that have the same author. In the event that the enclave fails to make forward progress and health tickets are not minted, then the AWDT expires and forces the reboot and re-imaging to a known good state to evict the malware from the computing device.
