Mutable Code Efficiencies in Measured Secure Boot for Hardware Root of Trust

A system comprising:

• a storage device including instructions for establishing a hardware root of trust among multiple security layers of a security framework;
• a memory circuit loaded with a reusable portion of the instructions for executing at least one shared function implemented by each of the security layers, and a layer-specific portion of the instructions for implementing a corresponding security layer based on the shared function;
• and
• a processing circuit that implements the security layers to sequentially establish the hardware root of trust one security layer at a time by loading the memory circuit with the layer-specific portion of the instructions that are executed to implement a current security layer prior to loading the memory circuit with the layer-specific portion of the instructions that are executed to implement a subsequent security layer.

A method for implementing a security framework among multiple security layers, the method comprising:

• loading, by a computing device, first mutable code in a memory of the computing device by storing a reusable part of the first mutable code and a remaining part of the first mutable code;
• responsive to executing the first mutable code to implement a first layer of the security framework, loading, by the computing device, subsequent mutable code in the memory by overwriting the remaining part of the first mutable code;
• and
• executing, by the computing device, the subsequent mutable code to implement a subsequent layer of the security framework by executing the reusable part of the first mutable code to perform at least one security function on behalf of the subsequent mutable code.