A method and system for enforcing access control to system resources and assets. Security attributes associated with devices that initiate transactions in the system are automatically generated and forwarded with transaction messages. The security attributes convey access privileges assigned to each initiator. One or more security enforcement mechanisms are implemented in the system to evaluate the security attributes against access policy requirements to access various system assets and resources, such as memory, registers, address ranges, etc. If the privileges identified by the security attributes indicate the access request is permitted, the transaction is allowed to proceed. The security attributes of the initiator scheme provides a modular, consistent secure access enforcement scheme across system designs.