55% Faster Post-Quantum Cryptography Enabled by Optimized OptHQC Implementation
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The growing threat to current encryption methods drives urgent research into post-quantum cryptography, but implementing these new systems often introduces significant performance challenges. To address this, Ben Dong, Hui Feng, and Qian Wang from the University of California, Merced, present OptHQC, a substantially improved implementation of the Hamming Quasi-Cyclic code-based cryptographic scheme. This work delivers a comprehensive optimisation of HQC across all critical stages, key generation, encryption, and decryption, by exploiting data sparsity and leveraging modern processor capabilities.
The team accelerates polynomial operations, optimises hash computations, and transforms complex calculations into efficient lookup table indexing, ultimately achieving an average 55% speedup over existing HQC implementations on standard CPU hardware. This advance represents a significant step towards practical, high-performance post-quantum cryptography, paving the way for secure communication in a future threatened by quantum computers. This work began with a detailed profiling of HQC’s computational stages, identifying hashing, syndrome computation, and decoding as performance bottlenecks. To accelerate hashing, scientists implemented a lane-interleaved Keccak (SHAKE) function with unrolled rounds, aligned loads and stores, and absorb/squeeze fusion, integrating this kernel into the HQC codebase, reducing seed expansion and PRNG time by a factor of two. Further improvements focused on vector multiplication, where the team implemented an efficient sparse × dense vector algorithm utilizing a polynomial shifting technique, resulting in approximately a 22% speedup during key generation, a 60% speedup during encryption, and a 35% speedup during decryption. Researchers replaced costly multiplications with precomputed lookup tables, transforming syndrome computation and error vector recovery into constant-time, cache-efficient XOR and shift operations that also preserved side-channel resistance. Overall, the OptHQC implementation achieved an average 55% speedup over the reference HQC implementation on standard CPU architectures, demonstrating a substantial advancement in the practicality of code-based post-quantum cryptography.,. Optimized HQC Implementation Achieves 55% Speedup The OptHQC implementation delivers substantial performance gains for the HQC code-based post-quantum cryptographic scheme, addressing a critical need for efficient post-quantum cryptography. Researchers achieved an average speedup of 55% over the reference HQC implementation on standard CPUs through a comprehensive analysis and optimization of each computational stage. Profiling revealed that hashing, sampling, and the concatenated Reed-Muller/Reed-Solomon decoding processes represent the dominant contributors to runtime, motivating targeted optimizations within these areas.
The team achieved significant gains through an optimized lane-interleaved Keccak (SHAKE) implementation, incorporating unrolled rounds, aligned loads/stores, and absorb/squeeze fusion. The implementation of a sparse × dense vector algorithm, utilizing a polynomial shifting technique, resulted in roughly 22% speedup during key generation, 60% during encryption, and 35% during decryption. The most computationally intensive operations, syndrome computation and error vector recovery, were optimized by replacing costly multiplications with precomputed lookup tables, transforming the operations into constant-time, cache-efficient XOR and shift operations while preserving side-channel resistance. These results demonstrate a significant advancement in the practical implementation of HQC, paving the way for its deployment in future secure communication systems.,. OptHQC Achieves 55% Speedup in Encryption This work presents a significant advancement in the implementation of the HQC post-quantum key encapsulation mechanism, addressing a critical need for efficient cryptographic solutions in the face of emerging quantum computing threats. Researchers developed OptHQC, an optimized implementation of HQC, achieving an average 55% speedup over existing implementations on standard CPU architectures. This improvement stems from a comprehensive analysis of HQC’s computational blocks and the application of targeted optimizations across key stages, key generation, encryption, and decryption.
The team’s approach focuses on accelerating polynomial operations through sparsity exploitation, leveraging instruction-level parallelism with techniques like AVX2, and transforming computationally intensive operations into efficient table lookups. Specifically, the optimized sparse-by-dense polynomial multiplication delivers up to 40% faster encryption, while a table-driven Reed-Solomon encoder and decoder significantly reduce the runtime of field multiplications. These optimizations not only enhance HQC’s efficiency but also contribute to its resistance against side-channel attacks, demonstrating the potential of memory-efficient design for code-based post-quantum cryptography on general-purpose platforms.
This research represents a valuable contribution to the field, paving the way for more practical and secure post-quantum cryptographic systems. 👉 More information 🗞 OptHQC: Optimize HQC for High-Performance Post-Quantum Cryptography 🧠 ArXiv: https://arxiv.org/abs/2512.12904 Tags: