Abstract:
With the increasing demand for low-latency and high-throughput requirements across emerging applications (for example, 5G/6G and the cloud), it has become imperative to offload compute-intensive tasks such as cryptographic processing to specialized accelerators. Given that ASIC-based cryptographic accelerators hinder flexibility, and are unsuitable for dynamic workloads, cloud providers (for example, AWS, Azure, Alibaba, and Google) and telecom operators use FPGA-based accelerators. The state-of-the-art FPGA-based accelerators are designed for high throughput or power efficiency, and they scale by replicating the high-throughput or power-efficient cryptographic cores, which may not be an optimal design for a given workload. We propose the concept of an “Asymmetric Cryptographic Core” to optimize CPU utilization by offloading cryptographic operations. Unlike traditional symmetric cores, our design introduces multiple variants of a specific cryptographic core, each optimized for different performance characteristics such as throughput, power efficiency, and resource usage. These core variants are deployed on an FPGA, dynamically selected based on real-time network workload distribution. This approach enables more efficient use of FPGA resources and delivers improved performance under varying workload conditions. We implemented the Rocca-S algorithm in the FPGA board and designed the variants of the small, medium, and large Rocca-S algorithms. These variants are optimised in terms of throughput, power efficiency, and resource usage. To scale these multiple cryptographic cores and process data streams in parallel, we implemented a load balancer that decides which data packet is supposed to be scheduled to the respective cryptographic core. These choices of asymmetric cryptographic core and scheduling policies will depend upon the deployer’s requirements and varying work-load conditions, to prioritise either throughput, power and resource utilisation of the system. The results showed that the combination of asymmetric cryptographic cores’ performance was comparable with the combination of symmetric cores in terms of throughput, resource and power efficiency, and as the workload distribution varies over time, we observed that the choice of asymmetric and symmetric cores changes in terms of throughput, power efficiency and resource efficiency.