Post-quantum cryptography (PQC) has garnered significant attention across various communities, particularly with the National Institute of Standards and Technology (NIST) advancing to the fourth round of PQC standardization. One of the leading candidates is Hamming Quasi-Cyclic (HQC), which received a significant update on February 23, 2024. This update, which introduces a classical dense-dense multiplication approach, has no known dedicated hardware implementations yet. The innovative Core-V eXtension InterFace (CV-X-IF) is a communication interface for RISC-V processors that significantly facilitates the integration of new instructions to the Instruction Set Architecture (ISA), through tightly connected accelerators. In this paper, we present a TightlY-coupled accelerator for RISC-V for Code-based cryptogrAphy (TYRCA), proposing the first fully tightly-coupled hardware implementation of the HQC-PQC algorithm, leveraging the CV-X-IF. The proposed architecture is implemented on the Xilinx Kintex-7 FPGA. Experimental results demonstrate that TYRCA reduces the execution time by 94% to 96% for HQC-128, HQC-192, and HQC-256, showcasing its potential for efficient HQC code-based cryptography.

HQC is a quantum-resistant cryptographic key encapsulation mechanism, recently selected by NIST as a future standard. Polynomial multiplication is one of the most critical operations in HQC. Due to side-channel security concerns, the previously-used sparse-dense method was recently replaced by classical dense-dense multiplication implemented using Karatsuba’s algorithm. This change has made polynomial multiplication the primary performance bottleneck, accounting for approximately 95% of the total execution time. This paper presents an alternative polynomial multiplication technique for HQC: the Frobenius Additive Fast Fourier Transform (FAFFT), which provides significant algorithmic-level performance improvements. We also present ANDROMEDA, the first state-of-the-art hardware implementation of FAFFT, and evaluate its performance impact by integrating our solution in a resourceconstrained RISC-V-based System-on-Chip scenario. Experimental results show that our solution improves HQC performance by approximately $9.64 \times$ and $19.22 \times$ across its security levels, making HQC more practical for real-world deployment.

International audience

International audience

The description of the physical noise source is of utmost importance for any TRNG certification. In the case of ring oscillators, Allan variance is a reliable and comprehensive tool which enables the distinction between the jitter coming from flicker noise (autocorrelated) and from thermal noise (random). In this paper, we realize measurements directly on the analog source of numerous TRNG structures: a ring oscillator. Our data, along with evidence from the literature, indicates the presence of a third noise source. The quantization noise has not been so far taken into consideration, but is unquestionably present in all TRNG reliant on jitter. Its importance is key to an accurate estimation of thermal noise contribution, which can be shadowed by it. Measurements presented in this paper show that insufficient sampling (i.e. higher quantization noise) can lead to an overestimation of jitter coming from thermal noise and therefore an overestimation of the calculated entropy. The latter is the only type of noise considered reliable in currently existing ring oscillator-based TRNG models. As a rule of thumb, three orders of magnitude between the sampling and the sampled signal are necessary in order to determine the thermal noise jitter correctly.

This paper focuses on road traffic monitoring using sounds and proposes, more specifically, a microphone array design methodology for observing vehicle trajectory from acoustic-based correlation functions. In a former work, authors have shown that combining generalized cross correlation (GCC) functions and a particle filter onto the audio signals simultaneously acquired by two sensors placed near the road allows the joint estimation of the speed and the wheelbase length of road vehicles as they pass by. This is mainly due to the broadband nature of the tire/road noise, which makes their spatial dissociation possible by means of an appropriate GCC processor. At the time, nothing has been said about the best distance to chose between the sensors. A methodology is proposed here to find this optimum, which is expected to improve the observation quality and, thus, the tracking performance. Theoretical developments of this paper are partially assessed with preliminary experiments.