Unified Hardware Accelerator Bridges FFT and NTT for Post-Quantum Cryptography and Digital Signal Processing

Researchers Rishabh Shrivastava, Chaitanya Prasad Ratnala, Durga Manasa Puli, and Utsav Banerjee published A Unified Hardware Accelerator for Fast Fourier Transform and Number Theoretic Transform, detailing a novel FPGA-based design that integrates both FFT and NTT operations. This innovation enables efficient processing of digital signal applications alongside post-quantum cryptographic algorithms like ML-KEM and ML-DSA, demonstrating the potential for versatile hardware solutions in emerging security frameworks.

Researchers developed a unified hardware accelerator supporting both 512-point complex FFT and 256-point NTT for NIST-standardized post-lattice cryptographic algorithms ML-KEM and ML-DSA. The design leverages existing FFT arithmetic circuitry, adding only modular reduction circuits and control logic modifications. Performance matches state-of-the-art FPGA implementations, demonstrating how FFT accelerators can be adapted to support NTT, enabling versatile use in both digital signal processing and lattice-based cryptography applications.

In an era where quantum computing poses a significant threat to current cryptographic systems, the development of secure alternatives is becoming increasingly critical. Post-quantum cryptography aims to create algorithms resistant to quantum attacks, ensuring data security in the future. This article explores how Field-Programmable Gate Arrays (FPGAs) are emerging as a pivotal technology in this quest, particularly in implementing NIST-standardized protocols like CRYSTALS-Kyber and Dilithium.

FPGAs are semiconductor devices known for their flexibility and reconfigurability. Unlike traditional processors, they can be programmed after manufacturing to adapt to specific tasks, making them ideal for cryptographic applications that require frequent updates or optimizations. This adaptability is crucial as post-quantum algorithms evolve.

The implementation of post-quantum cryptography on FPGAs involves several key techniques. One such method is the Number Theoretic Transform (NTT), essential for polynomial multiplication in lattice-based cryptography. NTT accelerates these operations, significantly enhancing performance while maintaining security. Engineers are also focusing on optimizing resource usage to balance speed and energy efficiency. This optimization ensures that FPGA-based solutions remain practical for real-world applications, addressing challenges like limited memory bandwidth and computational resources.

CRYSTALS-Kyber and Dilithium are leading candidates in NIST’s standardization process. These algorithms leverage lattice-based cryptography, offering robust security against quantum threats. Their implementation on FPGAs represents a significant step towards securing communication channels in the quantum era.

The integration of post-quantum cryptographic protocols with FPGA technology marks a crucial advancement in data security. By leveraging NTT and optimizing resource utilization, researchers are paving the way for secure, efficient solutions that can adapt to future challenges. As quantum computing progresses, these innovations will play a vital role in safeguarding digital communications, ensuring continued trust and security in an increasingly connected world.

In summary, FPGAs are not just tools for today’s cryptographic needs but are foundational to securing our communication infrastructure against the emerging threats of quantum computing.