An apparatus comprising a CPU core configured to execute instructions and consume data. The apparatus includes a memory configured to store the instructions and the data. A memory protection shim is coupled to the CPU core and the memory. The memory protection shim is configured to perform transformations over digital blocks to perform at least one of authentication or decryption of the digital blocks received from the memory. The memory protection shim is coupled to the CPU core in a fashion that prevents egress of the digital blocks or ingress of other external digital blocks between the memory protection shim and the CPU core.