RFC 9802: Use of the HSS and XMSS Hash-Based Signature Algorithms in Internet X.509 Public Key Infrastructure

This document specifies algorithm identifiers and ASN.1 encoding formats for the following stateful Hash-Based Signature (HBS) schemes: Hierarchical Signature System (HSS), eXtended Merkle Signature Scheme (XMSS), and XMSS (a multi-tree variant of XMSS). This specification applies to the Internet X.509 Public Key Infrastructure (PKI) when digital signatures are used to sign certificates and certificate revocation lists (CRLs).