On-the-fly decryption engine FRTDEC allows to decrypt on-the-fly AXI traffic based on the read request address information. Four independent and non-overlapping encrypted regions can be defined in FRTDEC, with optional execute-only or execute-never enforcement per region. FRTDEC is using AES-128 in counter mode to achieve the lowest possible latency. As a consequence, each time the content of one encrypted region is changed the entire region must be re-encrypted with a different cryptographic context (key or initialization vector). This constraint makes FRTDEC suitable to decrypt read-only data or code, stored for example in external NOR Flash memory
