Efficient SIMD based Implementation of Xoodyak

Abstract

Modern computing devices—particularly in the domains of the Internet of Things (IoT), mobile computing, and embedded systems—often operate under severe resource constraints in terms of processing power, memory (RAM/ROM), bandwidth, and battery life. Devices such as IoT sensors, smart cards, medical implants, RFID tags, and wearable systems typically rely on low-power hardware, including 8-bit microcontrollers with only a few kilobytes of memory. Conventional cryptographic algorithms are frequently unsuitable for such environments, as they may consume excessive power, introduce unacceptable latency, or fail to execute altogether. Lightweight cryptography addresses these challenges by providing cryptographic primitives specifically designed to operate efficiently on constrained hardware. With the rapid growth of IoT, billions of low-power devices are being deployed annually, all of which require fundamental security services such as encryption for data privacy, authentication for identity verification, and integrity protection to detect tampering. In response, international standardization bodies such as NIST and ISO have initiated efforts to define lightweight cryptographic standards. Notably, NIST’s Lightweight Cryptography Project aims to standardize algorithms that offer an effective balance between security and performance in resource-limited environments. Xoodyak is a modern lightweight cryptographic scheme developed for constrained platforms including IoT devices, embedded systems, and other resource-limited applications. It supports authenticated encryption, hashing, and pseudo-random number generation within a compact and efficient design, making it well suited for environments with strict limitations on memory, power, and computational capacity. Xoodyak was designed by Guido Bertoni, Joan Daemen, Michael Peeters, and Gilles Van Assche, who are also among the creators of Keccak (SHA-3). The scheme is built around the Xoodoo permutation, from which it derives its name, and was submitted to NIST’s Lightweight Cryptography Project, where it was recognized for its strong security properties and efficient performance across diverse platforms. Although Xoodyak is highly efficient on 8-bit, 16-bit, and 32-bit microcontrollers due to its compact code size and reliance on a single permutation for multiple cryptographic services, its design also enables a high degree of parallelism. This characteristic makes it suitable for deployment on powerful server-class processors that manage large numbers of constrained devices. In this work, we explore SIMD-based implementations of Xoodyak on modern Intel processors supporting AVX2 and AVX-512 instruction sets. While the eXtended Keccak Code Package (XKCP) provides up to 16-way parallelization, we investigate alternative SIMD parallelization paradigms capable of executing up to 512 parallel instances simultaneously.