Bitstream encryption and authentication with AES-GCM in dynamically reconfigurable systems

Abstract

A high-speed and secure dynamic partial reconfiguration (DPR) system is realized with AES-GCM that guarantees both confidentiality and authenticity of FPGA bitstreams. In DPR systems, bitstream authentication is essential for avoiding fatal damage caused by unintended bitstreams. An encryption-only system can prevent bitstream cloning and reverse engineering, but cannot prevent erroneous or malicious bitstreams from being configured. Authenticated encryption is a relatively new concept that provides both message encryption and authentication, and AES-GCM is one of the latest authenticated encryption algorithms suitable for hardware implementation. We implemented the AES-GCM-based DPR system targeting the Virtex-5 device on an off-the-shelf board, and evaluated its throughput and hardware resource utilization. For comparison, we also implemented AES-CBC and SHA-256 modules on the same device. The experimental results showed that the AES-GCM-based system achieved higher throughput with less resource utilization than the AES/SHA-based system. The AES-GCM-module achieved more than 1 Gbps throughput and the entire system achieved about 800 Mbps throughput with reasonable resource utilization. This paper clarifies the advantage of using AES-GCM for protecting DPR systems.