Use of the HSS/LMS Hash-Based Signature Algorithm with CBOR Object Signing and Encryption (COSE)
RFC 8778

Document Type RFC - Proposed Standard (April 2020; No errata)
Author Russ Housley 
Last updated 2020-04-13
Replaces draft-housley-suit-cose-hash-sig
Stream IETF
Formats plain text html xml pdf htmlized bibtex
Reviews
Stream WG state Submitted to IESG for Publication
Document shepherd Ivaylo Petrov
Shepherd write-up Show (last changed 2019-05-29)
IESG IESG state RFC 8778 (Proposed Standard)
Consensus Boilerplate Yes
Telechat date
Responsible AD Roman Danyliw
Send notices to Ivaylo Petrov <ivaylo@ackl.io>
IANA IANA review state IANA OK - Actions Needed
IANA action state RFC-Ed-Ack
IANA expert review state Expert Reviews OK


Internet Engineering Task Force (IETF)                        R. Housley
Request for Comments: 8778                                Vigil Security
Category: Standards Track                                     April 2020
ISSN: 2070-1721

   Use of the HSS/LMS Hash-Based Signature Algorithm with CBOR Object
                     Signing and Encryption (COSE)

Abstract

   This document specifies the conventions for using the Hierarchical
   Signature System (HSS) / Leighton-Micali Signature (LMS) hash-based
   signature algorithm with the CBOR Object Signing and Encryption
   (COSE) syntax.  The HSS/LMS algorithm is one form of hash-based
   digital signature; it is described in RFC 8554.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc8778.

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction
     1.1.  Motivation
     1.2.  Terminology
   2.  LMS Digital Signature Algorithm Overview
     2.1.  Hierarchical Signature System (HSS)
     2.2.  Leighton-Micali Signature (LMS)
     2.3.  Leighton-Micali One-Time Signature (LM-OTS) Algorithm
   3.  Hash-Based Signature Algorithm Identifiers
   4.  Security Considerations
   5.  Operational Considerations
   6.  IANA Considerations
     6.1.  COSE Algorithms Registry Entry
     6.2.  COSE Key Types Registry Entry
     6.3.  COSE Key Type Parameters Registry Entry
   7.  References
     7.1.  Normative References
     7.2.  Informative References
   Appendix A.  Examples
     A.1.  Example COSE Full Message Signature
     A.2.  Example COSE_Sign1 Message
   Acknowledgements
   Author's Address

1.  Introduction

   This document specifies the conventions for using the Hierarchical
   Signature System (HSS) / Leighton-Micali Signature (LMS) hash-based
   signature algorithm with the CBOR Object Signing and Encryption
   (COSE) [RFC8152] syntax.  The LMS system provides a one-time digital
   signature that is a variant of Merkle Tree Signatures (MTS).  The HSS
   is built on top of the LMS system to efficiently scale for a larger
   number of signatures.  The HSS/LMS algorithm is one form of a hash-
   based digital signature, and it is described in [HASHSIG].  The HSS/
   LMS signature algorithm can only be used for a fixed number of
   signing operations.  The number of signing operations depends upon
   the size of the tree.  The HSS/LMS signature algorithm uses small
   public keys, and it has low computational cost; however, the
   signatures are quite large.  The HSS/LMS private key can be very
   small when the signer is willing to perform additional computation at
   signing time; alternatively, the private key can consume additional
   memory and provide a faster signing time.  The HSS/LMS signatures
   [HASHSIG] are currently defined to use exclusively SHA-256 [SHS].

1.1.  Motivation

   Recent advances in cryptanalysis [BH2013] and progress in the
   development of quantum computers [NAS2019] pose a threat to widely
   deployed digital signature algorithms.  As a result, there is a need
   to prepare for a day that cryptosystems, such as RSA and DSA, that
   depend on discrete logarithm and factoring cannot be depended upon.

   If large-scale quantum computers are ever built, these computers will
   have more than a trivial number of quantum bits (qubits), and they
   will be able to break many of the public-key cryptosystems currently
   in use.  A post-quantum cryptosystem [PQC] is a system that is secure
   against such large-scale quantum computers.  When it will be feasible
   to build such computers is open to conjecture; however, RSA
   [RFC8017], DSA [DSS], Elliptic Curve Digital Signature Algorithm
   (ECDSA) [DSS], and Edwards-curve Digital Signature Algorithm (EdDSA)
   [RFC8032] are all vulnerable if large-scale quantum computers come to
   pass.

   Since the HSS/LMS signature algorithm does not depend on the
Show full document text