A system-on-chip (SoC) includes a host CPU on a CPU fabric, the host CPU including multiple processor cores, each associated with multiple security attributes. The SoC includes a secure asset on a network-on-chip and a security co-processor. The security co-processor includes circuitry to detect requests from the processor cores targeting the secure asset and security function processing requests, to determine, based on associated security attributes, whether the core or function is authorized to access the secure asset, to allow the request to be issued, if the core or function is so authorized, and to prevent its issuance, if not. The determination may be dependent on a signal from the CPU fabric indicating whether the host CPU can modify its security attributes or they are locked down. The security co-processor may have the highest security level and may be the only master on the SoC that can access the secure asset.