Stateless Hash-Based Digital Signature Standard: Federal Information Processing Standards 205

In an era marked by escalating cyber threats and the looming specter of quantum computing, safeguarding sensitive information is more critical than ever. This FIPS publication, NIST FIPS 205, stands as a critical bulwark in the face of these challenges. It introduces the **Stateless Hash-Based Digital Signature Algorithm (SLH-DSA)**, a cutting-edge digital signature scheme meticulously designed to withstand the threat posed by future quantum computers. This document delves into the intricate mathematical workings of SLH-DSA, providing a comprehensive guide to its key generation, signature generation, and signature verification processes. The publication further outlines 12 approved parameter sets, each offering distinct levels of security strength tailored to different application needs, and elucidating the precise instantiation of various hash functions and pseudorandom functions. This document also examines the intricate components that underpin the SLH-DSA scheme, including the Winternitz One-Time Signature Plus scheme (WOTS+), the eXtended Merkle Signature Scheme (XMSS), the Hypertree, and the Forest of Random Subsets (FORS). For those concerned with the implications of quantum computing on current cryptographic systems, this FIPS publication is a must-read. It offers a deep understanding of SLH-DSA's structure and function, empowering researchers, practitioners, and policymakers to navigate the complexities of post-quantum cryptography and implement this groundbreaking technology to secure our digital future. This annotated edition illustrates the capabilities of the AI Lab for Book-Lovers to add context and ease-of-use to manuscripts. It includes publishing information; abstracts; viewpoints; learning aids; and references.