Rethinking Secure FPGAs: Towards a Cryptography-friendly Configurable Cell Architecture and its Automated Design Flow

This work proposes the first fine-grained configurable cell array specifically tailored for the implementation of cryptographic algorithms that can be configured using widely adopted hardware description languages. Our solution can be added as a small, crypto-friendly reconfigurable hardware block to be included as an application-specific configurable building block in the next generation of FPGAs, exactly like DSP slices and embedded memory blocks were added in the past. Another application scenario uses our configurable cell array as a small embedded FPGA (eFPGA) which we envision to be added to an ASIC design or a microprocessor. This will solve the need for so-called cryptographic agility, allowing cryptographic algorithms to be upgraded or updated depending on newly detected vulnerabilities or changing standards. We focus on block ciphers and we derive the most suitable cell structure for mapping state-of-the-art algorithms. We develop the related automated design flow, exploiting the synthesis capabilities of Synopsys Design Compiler. We evaluate the performance of our solution by mapping a number of well-known ciphers onto our new cells. The obtained results show that the proposed architecture drastically outperforms commercial FPGAs in terms of silicon area and configuration memory resources, while obtaining a similar throughput.