Efficient Implementations of AIMer Post-Quantum Signature Scheme for Low-End to High-End IoT Devices

Post-quantum cryptography (PQC) is becoming increasingly critical for securing Internet of Things (IoT) applications against potential threats posed by quantum computers. However, cryptographic schemes based on mathematically hard problems, such as lattice-based constructions, may face reduced security margins due to ongoing cryptanalytic advancements. In IoT use cases requiring long-term deployment without guaranteed secure updates, symmetric-based signature schemes, such as <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathsf {SPHINCS+}$ </tex-math></inline-formula>, whose security relies solely on symmetric primitives, are considered robust alternatives. Among these, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textsf {AIMer}$ </tex-math></inline-formula>, selected as a finalist in the KpqC competition, is emerging as a promising candidate. This article presents optimized software implementations of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textsf {AIMer}$ </tex-math></inline-formula> for various IoT platforms, ranging from low-end to high-end devices. We propose memory-optimized and time–memory tradeoff implementations for resource-constrained ARM Cortex-M4 devices, and single instruction multiple data (SIMD)-accelerated implementations for AArch64 and AVX2 architectures. Furthermore, we conduct a comprehensive performance evaluation comparing our optimized implementations with other PQC signature schemes. Our results show that <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textsf {AIMer}$ </tex-math></inline-formula> achieves significantly smaller signature sizes and faster key generation and signing compared to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathsf {SPHINCS+}$ </tex-math></inline-formula> across all security levels, making it a viable option for long-term IoT deployment.