Method for securing runtime execution flow

A runtime security system, comprising:

• a shared core configured to execute processes having varying levels of trustworthiness configured to receive non-maskable security services requests;
• an execution monitor configured to monitor the execution of the shared core further comprising a timer, a policy table, and an execution monitor state machine;
• secure assets including cryptographic keys;
• and immutable security service functions configured to enable access to the secure assets in response to non-maskable secure services requests, wherein the execution monitor is configured to:
• detect that the shared core has received a non-maskable secure services request;
• verify that an instruction related to the non-maskable secure services request is valid during a temporary window of access based upon a state of the execution monitor, a received command, and a requestor ID:
• and
• set a privilege level of the instruction based upon a policy evaluation using the policy table;
• wherein the execution monitor is further configured to set the timer related to an expected reaction time of the shared core to the non-maskable secure services request.

A method of monitoring a shared core configured to perform functions having varying levels of trustworthiness by an execution monitor, wherein the execution monitor includes a timer, a policy table, and an execution monitor state machine, the method comprising:

• receiving a secure boot request by a shared core;
• detecting, by the execution monitor, that the shared core has received the secure boot request;
• verifying that the secure boot request is valid during a temporary window of access based upon a state of the execution monitor, a received command, and a requestor ID:
• and
• allowing the shared core to securely boot when the secure boot request is valid;
• setting, by the execution monitor, the timer related to an expected reaction time of the shared core to the non-maskable secure services request.