LAMPS - Limited Additional Mechanisms for PKIX and SMIME D. Van Geest Internet-Draft CryptoNext Security Intended status: Standards Track K. Bashiri Expires: 26 January 2025 BSI S. Fluhrer Cisco Systems S. Gazdag genua GmbH S. Kousidis BSI 25 July 2024 Internet X.509 Public Key Infrastructure: Algorithm Identifiers for HSS and XMSS draft-ietf-lamps-x509-shbs-04 Abstract This document specifies algorithm identifiers and ASN.1 encoding formats for the Stateful Hash-Based Signature Schemes (S-HBS) Hierarchical Signature System (HSS), eXtended Merkle Signature Scheme (XMSS), and XMSS^MT, a multi-tree variant of XMSS. This specification applies to the Internet X.509 Public Key infrastructure (PKI) when those digital signatures are used in Internet X.509 certificates and certificate revocation lists. About This Document This note is to be removed before publishing as an RFC. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-ietf-lamps-x509-shbs/. Discussion of this document takes place on the LAMPS Working Group mailing list (mailto:spasm@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/spasm/. Subscribe at https://www.ietf.org/mailman/listinfo/spasm/. Source for this draft and an issue tracker can be found at https://github.com/x509-hbs/draft-x509-shbs. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Van Geest, et al. Expires 26 January 2025 [Page 1] Internet-Draft HSS and XMSS for X.509 July 2024 Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on 26 January 2025. Copyright Notice Copyright (c) 2024 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 Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3 3. Use Cases of S-HBS in X.509 . . . . . . . . . . . . . . . . . 3 4. Algorithm Identifiers and Parameters . . . . . . . . . . . . 4 4.1. HSS Algorithm Identifier . . . . . . . . . . . . . . . . 4 4.2. XMSS Algorithm Identifier . . . . . . . . . . . . . . . . 5 4.3. XMSS^MT Algorithm Identifier . . . . . . . . . . . . . . 5 5. Public Key Identifiers . . . . . . . . . . . . . . . . . . . 5 5.1. HSS Public Keys . . . . . . . . . . . . . . . . . . . . . 6 5.2. XMSS Public Keys . . . . . . . . . . . . . . . . . . . . 6 5.3. XMSS^MT Public Keys . . . . . . . . . . . . . . . . . . . 7 6. Key Usage Bits . . . . . . . . . . . . . . . . . . . . . . . 7 7. Signature Algorithms . . . . . . . . . . . . . . . . . . . . 8 7.1. HSS Signature Algorithm . . . . . . . . . . . . . . . . . 8 7.2. XMSS Signature Algorithm . . . . . . . . . . . . . . . . 8 7.3. XMSS^MT Signature Algorithm . . . . . . . . . . . . . . . 9 8. Key Generation . . . . . . . . . . . . . . . . . . . . . . . 9 9. ASN.1 Module . . . . . . . . . . . . . . . . . . . . . . . . 9 10. Security Considerations . . . . . . . . . . . . . . . . . . . 11 11. Backup and Restore Management . . . . . . . . . . . . . . . . 12 Van Geest, et al. Expires 26 January 2025 [Page 2] Internet-Draft HSS and XMSS for X.509 July 2024 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 13.1. Normative References . . . . . . . . . . . . . . . . . . 13 13.2. Informative References . . . . . . . . . . . . . . . . . 14 Appendix A. HSS X.509 v3 Certificate Example . . . . . . . . . . 15 Appendix B. XMSS X.509 v3 Certificate Example . . . . . . . . . 18 Appendix C. XMSS^MT X.509 v3 Certificate Example . . . . . . . . 24 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 33 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 33 1. Introduction Stateful Hash-Based Signature Schemes (S-HBS) such as HSS, XMSS and XMSS^MT combine Merkle trees with One Time Signatures (OTS) in order to provide digital signature schemes that remain secure even when quantum computers become available. Their theoretic security is well understood and depends only on the security of the underlying hash function. As such they can serve as an important building block for quantum computer resistant information and communication technology. The private key of S-HBS is a finite collection of OTS keys, hence only a limited number of messages can be signed and the private key's state must be updated and persisted after signing to prevent reuse of OTS keys. While the right selection of algorithm parameters would allow a private key to sign a virtually unbounded number of messages (e.g. 2^60), this is at the cost of a larger signature size and longer signing time. Due to the statefulness of the private key and the limited number of signatures that can be created, S-HBS might not be appropriate for use in interactive protocols. However, in some use cases the deployment of S-HBS may be appropriate. Such use cases are described and discussed later in Section 3. 2. Conventions and Definitions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 3. Use Cases of S-HBS in X.509 As many cryptographic algorithms that are considered to be quantum- resistant, S-HBS have several pros and cons regarding their practical usage. On the positive side they are considered to be secure against a classical as well as a quantum adversary, and a secure instantiation of S-HBS may always be built as long as a cryptographically secure hash function exists. Moreover, S-HBS offer Van Geest, et al. Expires 26 January 2025 [Page 3] Internet-Draft HSS and XMSS for X.509 July 2024 small public key sizes, and, in comparison to other post-quantum signature schemes, the S-HBS can offer relatively small signature sizes (for certain parameter sets). While key generation and signature generation may take longer than classical alternatives, fast and minimal verification routines can be built. The major negative aspect is the statefulness. Private keys always have to be handled in a secure manner, S-HBS necessitate a special treatment of the private key in order to avoid security incidents like signature forgery [MCGREW], [SP800208]. Therefore, for S-HBS, a secure environment MUST be used for key generation and key management. Note that, in general, root CAs offer such a secure environment and the number of issued signatures (including signed certificates and CRLs) is often moderate due to the fact that many root CAs delegate OCSP services or the signing of end-entity certificates to other entities (such as subordinate CAs) that use stateless signature schemes. Therefore, many root CAs should be able to handle the required state management, and S-HBS offer a viable solution. As the above reasoning for root CAs usually does not apply for subordinate CAs, it is NOT RECOMMENDED for subordinate CAs to use S-HBS for issuing end-entity certificates. Moreover, S-HBS MUST NOT be used for end-entity certificates. However, S-HBS MAY be used for code signing certificates, since they are suitable and recommended in such non-interactive contexts. For example, see the recommendations for software and firmware signing in [CNSA2.0]. Some manufactures use common and well-established key formats like X.509 for their code signing and update mechanisms. Also there are multi-party IoT ecosystems where publicly trusted code signing certificates are useful. 4. Algorithm Identifiers and Parameters In this document, we define new OIDs for identifying the different stateful hash-based signature algorithms. An additional OID is defined in [I-D.draft-ietf-lamps-rfc8708bis] and repeated here for convenience. For all of the OIDs, the parameters MUST be absent. 4.1. HSS Algorithm Identifier The object identifier and public key algorithm identifier for HSS is defined in [I-D.draft-ietf-lamps-rfc8708bis]. The definitions are repeated here for reference. The object identifier for an HSS public key is id-alg-hss-lms- hashsig: Van Geest, et al. Expires 26 January 2025 [Page 4] Internet-Draft HSS and XMSS for X.509 July 2024 id-alg-hss-lms-hashsig OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) alg(3) 17 } Note that the id-alg-hss-lms-hashsig algorithm identifier is also referred to as id-alg-mts-hashsig. This synonym is based on the terminology used in an early draft of the document that became [RFC8554]. The public key and signature values identify the hash function and the height used in the HSS/LMS tree. [RFC8554] and [SP800208] define these values, but an IANA registry [IANA-LMS] permits the registration of additional identifiers in the future. 4.2. XMSS Algorithm Identifier The object identifier for an XMSS public key is id-alg-xmss-hashsig: id-alg-xmss-hashsig OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) algorithms(6) 34 } The public key and signature values identify the hash function and the height used in the XMSS tree. [RFC8391] and [SP800208] define these values, but an IANA registry [IANA-XMSS] permits the registration of additional identifiers in the future. 4.3. XMSS^MT Algorithm Identifier The object identifier for an XMSS^MT public key is id-alg-xmssmt- hashsig: id-alg-xmssmt-hashsig OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) algorithms(6) 35 } The public key and signature values identify the hash function and the height used in the XMSS^MT tree. [RFC8391] and [SP800208] define these values, but an IANA registry [IANA-XMSS] permits the registration of additional identifiers in the future. 5. Public Key Identifiers Certificates conforming to [RFC5280] can convey a public key for any public key algorithm. The certificate indicates the algorithm through an algorithm identifier. An algorithm identifier consists of an OID and optional parameters. Van Geest, et al. Expires 26 January 2025 [Page 5] Internet-Draft HSS and XMSS for X.509 July 2024 [RFC8554] and [RFC8391] define the raw octet string encodings of the public keys used in this document. When used in a SubjectPublicKeyInfo type, the subjectPublicKey BIT STRING contains the raw octet string encodings of the public keys. This document defines ASN.1 OCTET STRING types for encoding the public keys when not used in a SubjectPublicKeyInfo. The OCTET STRING is mapped to a subjectPublicKey (a value of type BIT STRING) as follows: the most significant bit of the OCTET STRING value becomes the most significant bit of the BIT STRING value, and so on; the least significant bit of the OCTET STRING becomes the least significant bit of the BIT STRING. 5.1. HSS Public Keys The HSS public key identifier is as follows: pk-HSS-LMS-HashSig PUBLIC-KEY ::= { IDENTIFIER id-alg-hss-lms-hashsig -- KEY no ASN.1 wrapping -- PARAMS ARE absent CERT-KEY-USAGE { digitalSignature, nonRepudiation, keyCertSign, cRLSign } } The HSS public key is defined as follows: HSS-LMS-HashSig-PublicKey ::= OCTET STRING [RFC8554] defines the raw octet string encoding of an HSS public key using the hss_public_key structure. See [SP800208] and [RFC8554] for more information on the contents and format of an HSS public key. Note that the single-tree signature scheme LMS is instantiated as HSS with number of levels being equal to 1. 5.2. XMSS Public Keys The XMSS public key identifier is as follows: pk-XMSS-HashSig PUBLIC-KEY ::= { IDENTIFIER id-alg-xmss-hashsig -- KEY no ASN.1 wrapping -- PARAMS ARE absent CERT-KEY-USAGE { digitalSignature, nonRepudiation, keyCertSign, cRLSign } } The XMSS public key is defined as follows: XMSS-HashSig-PublicKey ::= OCTET STRING Van Geest, et al. Expires 26 January 2025 [Page 6] Internet-Draft HSS and XMSS for X.509 July 2024 [RFC8391] defines the raw octet string encoding of an HSS public key using the xmss_public_key structure. See [SP800208] and [RFC8391] for more information on the contents and format of an XMSS public key. 5.3. XMSS^MT Public Keys The XMSS^MT public key identifier is as follows: pk-XMSSMT-HashSig PUBLIC-KEY ::= { IDENTIFIER id-alg-xmssmt-hashsig -- KEY no ASN.1 wrapping -- PARAMS ARE absent CERT-KEY-USAGE { digitalSignature, nonRepudiation, keyCertSign, cRLSign } } The XMSS^MT public key is defined as follows: XMSSMT-HashSig-PublicKey ::= OCTET STRING [RFC8391] defines the raw octet string encoding of an HSS public key using the xmssmt_public_key structure. See [SP800208] and [RFC8391] for more information on the contents and format of an XMSS^MT public key. 6. Key Usage Bits The intended application for the key is indicated in the keyUsage certificate extension [RFC5280]. When one of the AlgorithmIdentifiers specified in this document appears in the SubjectPublicKeyInfo field of a certification authority (CA) X.509 certificate [RFC5280], the certificate key usage extension MUST contain at least one of the following values: digitalSignature, nonRepudiation, keyCertSign, or cRLSign. However, it MUST NOT contain other values. When one of these AlgorithmIdentifiers appears in the SubjectPublicKeyInfo field of an end entity X.509 certificate [RFC5280], the certificate key usage extension MUST contain at least one of the following values: digitalSignature or nonRepudiation. However, it MUST NOT contain other values. Note that for certificates that indicate id-alg-hss-lms-hashsig the above definitions are more restrictive than the requirement defined in Section 4 of [I-D.draft-ietf-lamps-rfc8708bis]. Van Geest, et al. Expires 26 January 2025 [Page 7] Internet-Draft HSS and XMSS for X.509 July 2024 7. Signature Algorithms This section identifies OIDs for signing using HSS, XMSS, and XMSS^MT. When these algorithm identifiers appear in the algorithm field as an AlgorithmIdentifier, the encoding MUST omit the parameters field. That is, the AlgorithmIdentifier SHALL be a SEQUENCE of one component, one of the OIDs defined in the following subsections. When the signature algorithm identifiers described in this document are used to create a signature on a message, no digest algorithm is applied to the message before signing. That is, the full data to be signed is signed rather than a digest of the data. For HSS, the signature value is described in section 6.4 of [RFC8554]. For XMSS and XMSS^MT the signature values are described in sections B.2 and C.2 of [RFC8391], respectively. The octet string representing the signature is encoded directly in the OCTET STRING without adding any additional ASN.1 wrapping. For the Certificate and CertificateList structures, the signature value is wrapped in the "signatureValue" OCTET STRING field. 7.1. HSS Signature Algorithm The HSS public key OID is also used to specify that an HSS signature was generated on the full message, i.e. the message was not hashed before being processed by the HSS signature algorithm. id-alg-hss-lms-hashsig OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) alg(3) 17 } The HSS signature is defined as follows: HSS-LMS-HashSig-Signature ::= OCTET STRING See [SP800208] and [RFC8554] for more information on the contents and format of an HSS signature. 7.2. XMSS Signature Algorithm The id-alg-xmss-hashsig public key OID is also used to specify that an XMSS signature was generated on the full message, i.e. the message was not hashed before being processed by the XMSS signature algorithm. The XMSS signature is defined as follows: Van Geest, et al. Expires 26 January 2025 [Page 8] Internet-Draft HSS and XMSS for X.509 July 2024 XMSS-HashSig-Signature ::= OCTET STRING See [SP800208] and [RFC8391] for more information on the contents and format of an XMSS signature. The signature generation MUST be performed according to 7.2 of [SP800208]. 7.3. XMSS^MT Signature Algorithm The id-alg-xmssmt-hashsig public key OID is also used to specify that an XMSS^MT signature was generated on the full message, i.e. the message was not hashed before being processed by the XMSS^MT signature algorithm. The XMSS^MT signature is defined as follows: XMSSMT-HashSig-Signature ::= OCTET STRING See [SP800208] and [RFC8391] for more information on the contents and format of an XMSS^MT signature. The signature generation MUST be performed according to 7.2 of [SP800208]. 8. Key Generation The key generation for XMSS and XMSS^MT MUST be performed according to 7.2 of [SP800208] 9. ASN.1 Module For reference purposes, the ASN.1 syntax is presented as an ASN.1 module here. This ASN.1 Module builds upon the conventions established in [RFC5911]. X509-SHBS-2024 { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-pkix1-shbs-2024(TBD) } DEFINITIONS IMPLICIT TAGS ::= BEGIN EXPORTS ALL; IMPORTS PUBLIC-KEY, SIGNATURE-ALGORITHM FROM AlgorithmInformation-2009 -- RFC 5911 [CMSASN1] { iso(1) identified-organization(3) dod(6) internet(1) Van Geest, et al. Expires 26 January 2025 [Page 9] Internet-Draft HSS and XMSS for X.509 July 2024 security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-algorithmInformation-02(58) } sa-HSS-LMS-HashSig, pk-HSS-LMS-HashSig FROM MTS-HashSig-2013 { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) id-smime(16) id-mod(0) id-mod-mts-hashsig-2013(64) }; -- -- Object Identifiers -- -- id-alg-hss-lms-hashsig is defined in [RFC8708] id-alg-xmss-hashsig OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) algorithms(6) 34 } id-alg-xmssmt-hashsig OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) algorithms(6) 35 } -- -- Signature Algorithms and Public Keys -- -- sa-HSS-LMS-HashSig is defined in [RFC8708] sa-XMSS-HashSig SIGNATURE-ALGORITHM ::= { IDENTIFIER id-alg-xmss-hashsig PARAMS ARE absent PUBLIC-KEYS { pk-XMSS-HashSig } SMIME-CAPS { IDENTIFIED BY id-alg-xmss-hashsig } } sa-XMSSMT-HashSig SIGNATURE-ALGORITHM ::= { IDENTIFIER id-alg-xmssmt-hashsig PARAMS ARE absent PUBLIC-KEYS { pk-XMSSMT-HashSig } SMIME-CAPS { IDENTIFIED BY id-alg-xmssmt-hashsig } } -- pk-HSS-LMS-HashSig is defined in [RFC8708] pk-XMSS-HashSig PUBLIC-KEY ::= { IDENTIFIER id-alg-xmss-hashsig -- KEY no ASN.1 wrapping -- PARAMS ARE absent CERT-KEY-USAGE { digitalSignature, nonRepudiation, keyCertSign, cRLSign } } Van Geest, et al. Expires 26 January 2025 [Page 10] Internet-Draft HSS and XMSS for X.509 July 2024 pk-XMSSMT-HashSig PUBLIC-KEY ::= { IDENTIFIER id-alg-xmssmt-hashsig -- KEY no ASN.1 wrapping -- PARAMS ARE absent CERT-KEY-USAGE { digitalSignature, nonRepudiation, keyCertSign, cRLSign } } -- -- Public Key (pk-) Algorithms -- PublicKeys PUBLIC-KEY ::= { -- This expands PublicKeys from RFC 5912 pk-HSS-LMS-HashSig | pk-XMSS-HashSig | pk-XMSSMT-HashSig, ... } -- -- Signature Algorithms (sa-) -- SignatureAlgs SIGNATURE-ALGORITHM ::= { -- This expands SignatureAlgorithms from RFC 5912 sa-HSS-LMS-HashSig | sa-XMSS-HashSig | sa-XMSSMT-HashSig, ... } END 10. Security Considerations The security requirements of [SP800208] MUST be taken into account. For S-HBS it is crucial to stress the importance of a correct state management. If an attacker were able to obtain signatures for two different messages created using the same OTS key, then it would become computationally feasible for that attacker to create forgeries [BH16]. As noted in [MCGREW] and [ETSI-TR-103-692], extreme care needs to be taken in order to avoid the risk that an OTS key will be reused accidentally. This is a new requirement that most developers will not be familiar with and requires careful handling. Various strategies for a correct state management can be applied: Van Geest, et al. Expires 26 January 2025 [Page 11] Internet-Draft HSS and XMSS for X.509 July 2024 * Implement a track record of all signatures generated by a key pair associated to a S-HBS instance. This track record may be stored outside the device which is used to generate the signature. Check the track record to prevent OTS key reuse before a new signature is released. Drop the new signature and hit your PANIC button if you spot OTS key reuse. * Use a S-HBS instance only for a moderate number of signatures such that it is always practical to keep a consistent track record and be able to unambiguously trace back all generated signatures. * Apply the state reservation strategy described in Section 5 of [MCGREW], where upcoming states are reserved in advance by the signer. In this way the number of state synchronisations between nonvolatile and volatile memory is reduced. 11. Backup and Restore Management Certificate Authorities have high demands in order to ensure the availability of signature generation throughout the validity period of signing key pairs. Usual backup and restore strategies when using a stateless signature scheme (e.g. SLH-DSA) are to duplicate private keying material and to operate redundant signing devices or to store and safeguard a copy of the private keying material such that it can be used to set up a new signing device in case of technical difficulties. For S-HBS such straightforward backup and restore strategies will lead to OTS reuse with high probability as a correct state management is not guaranteed. Strategies for maintaining availability and keeping a correct state are described in Section 7 of [SP800208]. 12. IANA Considerations One object identifier for the ASN.1 module in Appendix A is requested for the SMI Security for PKIX Module Identifiers (1.3.6.1.5.5.7.0) registry: +=========+========================+====================+ | Decimal | Description | References | +=========+========================+====================+ | TBD | id-mod-pkix1-shbs-2024 | [EDNOTE: THIS RFC] | +---------+------------------------+--------------------+ Table 1 Van Geest, et al. Expires 26 January 2025 [Page 12] Internet-Draft HSS and XMSS for X.509 July 2024 IANA has updated the "SMI Security for PKIX Algorithms" (1.3.6.1.5.5.7.6) registry [SMI-PKIX] with two additional entries: +=========+=======================+====================+ | Decimal | Description | References | +=========+=======================+====================+ | 34 | id-alg-xmss-hashsig | [EDNOTE: THIS RFC] | +---------+-----------------------+--------------------+ | 35 | id-alg-xmssmt-hashsig | [EDNOTE: THIS RFC] | +---------+-----------------------+--------------------+ Table 2 13. References 13.1. Normative References [I-D.draft-ietf-lamps-rfc8708bis] Housley, R., "Use of the HSS/LMS Hash-Based Signature Algorithm in the Cryptographic Message Syntax (CMS)", RFC 8708, DOI 10.17487/RFC8708, February 2020, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., Housley, R., and W. Polk, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, . [RFC5911] Hoffman, P. and J. Schaad, "New ASN.1 Modules for Cryptographic Message Syntax (CMS) and S/MIME", RFC 5911, DOI 10.17487/RFC5911, June 2010, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8391] Huelsing, A., Butin, D., Gazdag, S., Rijneveld, J., and A. Mohaisen, "XMSS: eXtended Merkle Signature Scheme", RFC 8391, DOI 10.17487/RFC8391, May 2018, . Van Geest, et al. Expires 26 January 2025 [Page 13] Internet-Draft HSS and XMSS for X.509 July 2024 [RFC8554] McGrew, D., Curcio, M., and S. Fluhrer, "Leighton-Micali Hash-Based Signatures", RFC 8554, DOI 10.17487/RFC8554, April 2019, . [SP800208] National Institute of Standards and Technology (NIST), "Recommendation for Stateful Hash-Based Signature Schemes", 29 October 2020, . 13.2. Informative References [BH16] Bruinderink, L. and S. Hülsing, "Oops, I did it again – Security of One-Time Signatures under Two-Message Attacks.", 2016, . [CNSA2.0] National Security Agency (NSA), "Commercial National Security Algorithm Suite 2.0 (CNSA 2.0) Cybersecurity Advisory (CSA)", 7 September 2022, . [ETSI-TR-103-692] European Telecommunications Standards Institute (ETSI), "State management for stateful authentication mechanisms", November 2021, . [IANA-LMS] IANA, "Leighton-Micali Signatures (LMS)", n.d., . [IANA-XMSS] IANA, "XMSS: Extended Hash-Based Signatures", n.d., . [MCGREW] McGrew, D., Kampanakis, P., Fluhrer, S., Gazdag, S., Butin, D., and J. Buchmann, "State Management for Hash- Based Signatures", 2 November 2016, . [RFC3279] Bassham, L., Polk, W., and R. Housley, "Algorithms and Identifiers for the Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 3279, DOI 10.17487/RFC3279, April 2002, . Van Geest, et al. Expires 26 January 2025 [Page 14] Internet-Draft HSS and XMSS for X.509 July 2024 [RFC8410] Josefsson, S. and J. Schaad, "Algorithm Identifiers for Ed25519, Ed448, X25519, and X448 for Use in the Internet X.509 Public Key Infrastructure", RFC 8410, DOI 10.17487/RFC8410, August 2018, . [RFC8411] Schaad, J. and R. Andrews, "IANA Registration for the Cryptographic Algorithm Object Identifier Range", RFC 8411, DOI 10.17487/RFC8411, August 2018, . [SMI-PKIX] IANA, "SMI Security for PKIX Algorithms", n.d., . Appendix A. HSS X.509 v3 Certificate Example This section shows a self-signed X.509 v3 certificate using HSS. Certificate: Data: Version: 3 (0x2) Serial Number: e8:91:d6:06:91:4f:ce:f3 Signature Algorithm: hss Issuer: C = US, ST = VA, L = Herndon, O = Bogus CA Validity Not Before: May 14 08:58:11 2024 GMT Not After : May 14 08:58:11 2034 GMT Subject: C = US, ST = VA, L = Herndon, O = Bogus CA Subject Public Key Info: Public Key Algorithm: hss hss public key: PQ key material: 00:00:00:01:00:00:00:05:00:00:00:04:c0:96:12: 8b:ea:38:30:78:eb:f6:fb:43:d7:7f:9f:9e:81:39: e2:7c:b9:34:4e:6e:53:19:f0:ee:68:75:85:83:d3: 2b:e9:7b:14:46:9e:4e:c5:e3:5a:18:0b:30:e5:13 X509v3 extensions: X509v3 Subject Key Identifier: 58:15:AB:F4:CF:03:69:02:60:7A:57:4D:C5:D5:B3:72: 8A:19:21:68 X509v3 Authority Key Identifier: 58:15:AB:F4:CF:03:69:02:60:7A:57:4D:C5:D5:B3:72: 8A:19:21:68 X509v3 Basic Constraints: critical CA:TRUE X509v3 Key Usage: critical Van Geest, et al. Expires 26 January 2025 [Page 15] Internet-Draft HSS and XMSS for X.509 July 2024 Certificate Sign, CRL Sign Signature Algorithm: hss Signature Value: 00:00:00:00:00:00:00:00:00:00:00:04:9c:37:52:ff:b9:d7: df:f5:5b:01:ba:50:c2:50:cc:6f:f3:b1:73:df:0c:2a:ea:b3: ed:96:1e:ce:e7:58:05:da:8d:a7:77:21:42:32:d9:f9:4a:4d: f7:2b:18:2a:1c:5c:69:03:f3:1c:9c:95:6d:31:9a:c9:ca:84: 4d:ae:b3:8b:c3:71:ac:3f:87:51:be:38:b4:bf:d9:dc:90:1f: 1e:54:bd:f9:1a:65:70:d4:46:b6:ad:4d:6d:16:b9:fb:29:f4: e3:86:42:4a:3f:a4:8f:01:84:9b:44:0b:23:22:9c:97:6d:d5: b9:26:39:11:ab:46:82:bd:10:6c:b4:7a:64:ed:c7:40:b0:33: f0:b5:81:1c:b4:41:54:9c:30:d9:d2:93:ba:48:8c:4f:d0:25: 41:60:7b:90:5e:12:20:b7:30:16:16:1e:b7:ee:d8:4b:ee:ed: 3c:70:fc:ff:36:18:aa:24:23:87:91:65:a8:95:2d:b6:1c:d1: 02:7b:70:81:8a:18:17:c0:45:62:fe:47:a1:3e:69:54:31:67: 58:9a:e1:e3:c9:8d:ee:1e:2a:d1:46:75:e9:e4:90:67:01:57: 92:54:db:b4:ea:de:8b:e7:eb:fc:27:80:9b:d5:da:e0:8e:b0: b3:08:ca:6f:a1:1c:f4:40:65:b0:f6:f8:c9:a7:97:04:c8:7c: 9e:56:ec:2f:4b:cd:45:8b:d7:e6:a7:50:c7:e6:21:2c:17:31: 23:11:7a:ae:9a:b5:84:5f:e6:5c:82:99:a8:3a:a9:91:87:9a: 24:5c:83:01:91:7c:fc:cd:be:2e:92:50:fb:12:11:96:08:0d: c9:24:0d:bb:6f:fb:59:05:af:7f:96:bc:a3:f4:58:e2:fa:0a: 4a:f2:4c:f7:b3:1b:81:dd:4a:41:a0:b1:dd:52:4c:bb:6d:c0: a8:d9:bb:29:c8:fc:e3:7e:f8:6a:e5:5e:c4:e4:e8:7c:0b:00: 87:15:75:a2:06:50:97:c6:1f:14:52:79:04:a8:9c:ec:b1:c7: 6a:46:33:98:b8:63:f7:a7:2c:d4:62:78:94:1c:5d:9d:4f:a6: 0a:ae:39:50:85:b2:09:8d:62:c9:4c:11:9f:0c:91:a5:ac:2d: 11:bd:71:b6:0c:ea:34:98:53:fc:2e:cc:7b:a4:9c:2e:7a:a4: 8d:e2:e8:8c:01:a9:9c:3e:b5:34:77:33:82:01:d4:ef:72:04: d6:5b:e5:f6:2c:1b:ae:86:c4:73:02:44:85:d6:f7:ac:a3:e8: f6:a9:b5:5c:6d:46:88:da:55:b8:2b:7a:4c:0c:9a:e7:cd:5d: 62:8a:ca:c8:96:ce:8d:71:7b:d2:c1:0d:9a:35:55:2b:84:3e: 0e:a5:fa:d6:a0:76:8e:23:b3:df:c9:3b:4f:68:56:1e:e9:3c: 79:5b:d3:25:54:11:ad:a6:ac:58:11:49:8f:4d:c4:c1:39:99: 76:3a:a6:d1:2f:57:ad:bf:7c:9d:57:cc:37:0d:29:84:29:7b: cb:46:85:c3:81:c5:33:9a:65:c3:2f:01:48:ca:44:6c:f1:84: 3d:d0:49:c2:c1:05:db:77:4c:b9:72:3d:6f:ce:69:f2:91:c6: 15:25:8f:da:38:7e:ef:5b:3e:5f:35:ab:a6:78:16:28:42:c1: 2c:2f:9e:11:53:2c:bd:c4:24:7b:e9:c4:ce:3d:d6:41:c7:5d: 92:91:c3:37:cb:72:44:d7:0d:70:85:13:0b:ac:b3:0f:b0:e5: e3:2e:48:b9:9c:b8:d7:3e:7c:50:69:03:7a:5f:ae:f8:6c:09: 61:97:6b:ce:cd:e5:f0:55:fe:05:f8:97:1d:9e:81:65:f5:ff: 9a:7a:8c:96:d8:f8:cf:d8:dc:55:ce:67:7a:00:6b:fd:bb:3f: 1b:3d:65:94:c1:5a:b6:a0:8e:be:a4:be:26:90:5f:1f:06:d4: ea:3f:a6:97:40:8e:bf:18:5c:92:0f:15:e3:05:4a:14:51:1e: 23:81:ef:cf:f7:a8:88:75:f8:2d:28:37:26:87:27:63:5c:01: 53:0e:5e:53:d2:a7:18:eb:2f:c0:82:49:05:b0:4d:33:6f:94: 10:91:77:f8:90:9e:ca:fe:bb:3d:c4:42:d6:89:84:98:42:f4: Van Geest, et al. Expires 26 January 2025 [Page 16] Internet-Draft HSS and XMSS for X.509 July 2024 24:b3:b4:db:5e:2b:66:a9:ff:6c:18:d4:79:f8:72:73:53:9b: 02:ed:04:73:77:a4:68:cf:4b:be:4b:16:50:62:87:f9:49:99: e3:a1:0c:42:92:bc:a9:e3:2d:22:82:35:7f:71:15:88:70:6a: 01:ab:44:64:ad:e5:52:d4:97:ee:bb:44:7b:6e:08:7f:dd:94: fd:c9:1c:6b:59:d1:92:51:29:03:ce:ec:bf:41:a5:14:69:54: 3a:b4:39:d9:44:5d:f1:b2:f4:5c:6b:9f:c9:5f:bb:fc:c8:c7: a3:8b:e1:ec:e2:d0:69:5a:40:1c:9c:9d:8a:3d:77:3b:c1:5d: c0:72:61:4b:37:c5:96:8c:6d:8b:f8:56:da:ac:3e:3c:72:09: ce:f6:c3:fe:5d:cf:37:d9:68:cd:a7:dd:f7:96:63:da:8c:1d: df:b8:32:cf:eb:97:11:83:fe:6b:aa:b9:e2:4b:b2:ea:62:73: c3:1c:e9:40:90:56:4f:12:c3:ba:f4:2b:d9:1c:50:cc:e0:51: d8:eb:bf:67:28:0c:2d:13:8d:b3:6f:13:6a:1d:a7:54:20:ba: 82:5b:b8:e5:1f:89:f1:67:26:c1:dc:1b:60:57:ed:a6:2c:f2: 17:01:7f:a5:e7:5c:64:c9:3c:08:f2:cf:48:ec:88:84:ef:03: c2:f5:eb:05:31:7d:fe:7f:3c:71:41:28:17:64:5f:b9:ec:54: 79:d0:b3:98:fb:84:9c:36:8b:43:0b:d4:c9:ec:09:4a:70:13: 62:f2:36:c8:b4:75:cc:2a:77:08:a0:9d:ef:19:d6:88:dc:e2: b2:4e:40:61:71:cb:c7:c3:de:16:6f:49:7f:5e:d5:17:00:00: 00:05:79:47:12:9f:ce:eb:1d:a8:fd:0d:b0:18:44:6a:ef:54: 28:46:e4:19:f6:2d:3e:74:bb:9d:36:0a:ae:67:4a:28:7a:1b: 80:39:a0:08:2a:28:a0:ec:55:ee:55:aa:a1:cc:94:d4:36:1a: b3:57:25:30:ad:2c:5e:63:ba:22:fc:aa:7a:59:64:f6:d8:03: 20:28:71:f9:dc:09:fa:4c:81:b9:64:1b:ad:ea:cb:db:18:17: 5d:d8:98:bd:d2:8d:c5:04:7c:5b:92:9a:89:f6:bc:d6:55:c7: 08:5d:3c:58:8e:18:ac:6f:88:a8:d7:9e:d4:ee:5d:f5:21:4e: a5:8b:19:5f:e3:f4:66:f9:25:4d:f9:c6:60:62:31:72:5c:34: 34:67:1a:a7:6a:7d:54:a3:d8:9b:1f:5b:f8:08:41:79:5b:43 Van Geest, et al. Expires 26 January 2025 [Page 17] Internet-Draft HSS and XMSS for X.509 July 2024 -----BEGIN CERTIFICATE----- MIIGnjCCAXagAwIBAgIJAOiR1gaRT87zMA0GCyqGSIb3DQEJEAMRMD8xCzAJBgNV BAYTAlVTMQswCQYDVQQIDAJWQTEQMA4GA1UEBwwHSGVybmRvbjERMA8GA1UECgwI Qm9ndXMgQ0EwHhcNMjQwNTE0MDg1ODExWhcNMzQwNTE0MDg1ODExWjA/MQswCQYD VQQGEwJVUzELMAkGA1UECAwCVkExEDAOBgNVBAcMB0hlcm5kb24xETAPBgNVBAoM CEJvZ3VzIENBME4wDQYLKoZIhvcNAQkQAxEDPQAAAAABAAAABQAAAATAlhKL6jgw eOv2+0PXf5+egTnifLk0Tm5TGfDuaHWFg9Mr6XsURp5OxeNaGAsw5ROjYzBhMB0G A1UdDgQWBBRYFav0zwNpAmB6V03F1bNyihkhaDAfBgNVHSMEGDAWgBRYFav0zwNp AmB6V03F1bNyihkhaDAPBgNVHRMBAf8EBTADAQH/MA4GA1UdDwEB/wQEAwIBBjAN BgsqhkiG9w0BCRADEQOCBREAAAAAAAAAAAAAAAAEnDdS/7nX3/VbAbpQwlDMb/Ox c98MKuqz7ZYezudYBdqNp3chQjLZ+UpN9ysYKhxcaQPzHJyVbTGaycqETa6zi8Nx rD+HUb44tL/Z3JAfHlS9+RplcNRGtq1NbRa5+yn044ZCSj+kjwGEm0QLIyKcl23V uSY5EatGgr0QbLR6ZO3HQLAz8LWBHLRBVJww2dKTukiMT9AlQWB7kF4SILcwFhYe t+7YS+7tPHD8/zYYqiQjh5FlqJUtthzRAntwgYoYF8BFYv5HoT5pVDFnWJrh48mN 7h4q0UZ16eSQZwFXklTbtOrei+fr/CeAm9Xa4I6wswjKb6Ec9EBlsPb4yaeXBMh8 nlbsL0vNRYvX5qdQx+YhLBcxIxF6rpq1hF/mXIKZqDqpkYeaJFyDAZF8/M2+LpJQ +xIRlggNySQNu2/7WQWvf5a8o/RY4voKSvJM97Mbgd1KQaCx3VJMu23AqNm7Kcj8 4374auVexOTofAsAhxV1ogZQl8YfFFJ5BKic7LHHakYzmLhj96cs1GJ4lBxdnU+m Cq45UIWyCY1iyUwRnwyRpawtEb1xtgzqNJhT/C7Me6ScLnqkjeLojAGpnD61NHcz ggHU73IE1lvl9iwbrobEcwJEhdb3rKPo9qm1XG1GiNpVuCt6TAya581dYorKyJbO jXF70sENmjVVK4Q+DqX61qB2jiOz38k7T2hWHuk8eVvTJVQRraasWBFJj03EwTmZ djqm0S9Xrb98nVfMNw0phCl7y0aFw4HFM5plwy8BSMpEbPGEPdBJwsEF23dMuXI9 b85p8pHGFSWP2jh+71s+XzWrpngWKELBLC+eEVMsvcQke+nEzj3WQcddkpHDN8ty RNcNcIUTC6yzD7Dl4y5IuZy41z58UGkDel+u+GwJYZdrzs3l8FX+BfiXHZ6BZfX/ mnqMltj4z9jcVc5negBr/bs/Gz1llMFatqCOvqS+JpBfHwbU6j+ml0COvxhckg8V 4wVKFFEeI4Hvz/eoiHX4LSg3JocnY1wBUw5eU9KnGOsvwIJJBbBNM2+UEJF3+JCe yv67PcRC1omEmEL0JLO0214rZqn/bBjUefhyc1ObAu0Ec3ekaM9LvksWUGKH+UmZ 46EMQpK8qeMtIoI1f3EViHBqAatEZK3lUtSX7rtEe24If92U/ckca1nRklEpA87s v0GlFGlUOrQ52URd8bL0XGufyV+7/MjHo4vh7OLQaVpAHJydij13O8FdwHJhSzfF loxti/hW2qw+PHIJzvbD/l3PN9lozafd95Zj2owd37gyz+uXEYP+a6q54kuy6mJz wxzpQJBWTxLDuvQr2RxQzOBR2Ou/ZygMLRONs28Tah2nVCC6glu45R+J8Wcmwdwb YFftpizyFwF/pedcZMk8CPLPSOyIhO8DwvXrBTF9/n88cUEoF2RfuexUedCzmPuE nDaLQwvUyewJSnATYvI2yLR1zCp3CKCd7xnWiNzisk5AYXHLx8PeFm9Jf17VFwAA AAV5RxKfzusdqP0NsBhEau9UKEbkGfYtPnS7nTYKrmdKKHobgDmgCCoooOxV7lWq ocyU1DYas1clMK0sXmO6Ivyqellk9tgDIChx+dwJ+kyBuWQbrerL2xgXXdiYvdKN xQR8W5Kaifa81lXHCF08WI4YrG+IqNee1O5d9SFOpYsZX+P0ZvklTfnGYGIxclw0 NGcap2p9VKPYmx9b+AhBeVtD -----END CERTIFICATE----- Appendix B. XMSS X.509 v3 Certificate Example This section shows a self-signed X.509 v3 certificate using XMSS. Van Geest, et al. Expires 26 January 2025 [Page 18] Internet-Draft HSS and XMSS for X.509 July 2024 Certificate: Data: Version: 3 (0x2) Serial Number: 54:7e:64:70:29:9e:03:c5:7a:a5:5c:78:d1:27:87:8c: 54:35:17:5d Signature Algorithm: xmss Issuer: C = FR, L = Paris, O = Bogus XMSS CA Validity Not Before: Jul 10 08:27:24 2024 GMT Not After : Jul 8 08:27:24 2034 GMT Subject: C = FR, L = Paris, O = Bogus XMSS CA Subject Public Key Info: Public Key Algorithm: xmss xmss public key: PQ key material: 00:00:00:01:2b:eb:bf:66:14:de:6f:96:5b:4d:2a: 50:00:7b:ad:5c:22:b0:13:79:72:02:14:a9:5f:fc: 96:e0:9b:78:8e:d6:be:8c:1c:70:3c:d8:dd:78:b2: 1a:14:47:be:1f:0d:74:72:3f:36:76:c2:cb:19:ad: 29:90:0b:82:de:9b:7f:df X509v3 extensions: X509v3 Subject Key Identifier: 62:CE:35:A5:47:77:FF:21:87:2E:BC:2D:27:E7:8E:F4: 35:6B:CF:D8 X509v3 Authority Key Identifier: 62:CE:35:A5:47:77:FF:21:87:2E:BC:2D:27:E7:8E:F4: 35:6B:CF:D8 X509v3 Basic Constraints: critical CA:TRUE X509v3 Key Usage: critical Certificate Sign, CRL Sign Signature Algorithm: xmss Signature Value: 00:00:00:00:e5:88:a8:b8:73:ad:4d:92:f8:5c:81:c5:8a:63: 57:6a:a7:3b:54:aa:b6:06:8a:d9:f1:c2:0b:c8:27:1e:4b:a2: cf:e2:da:44:ea:e8:f2:40:a8:b9:54:9c:49:36:12:24:df:74: ad:e5:29:ef:4f:da:88:0d:21:5d:3b:64:63:27:d0:84:b5:95: 7a:30:18:37:cd:34:17:dd:ac:9d:9e:48:db:74:07:79:84:21: 5a:f0:26:cd:21:64:7b:77:33:48:58:67:9b:2c:b2:85:6d:cc: ec:31:4b:2f:51:55:3a:85:e1:ca:04:15:ce:6e:47:39:f5:e9: 31:45:41:ed:71:c6:4f:96:f5:ae:64:6a:bd:72:d0:8c:17:02: 99:10:1d:14:34:ca:e5:47:e3:f7:66:96:96:11:d5:97:76:76: 83:f1:84:a5:b6:00:5e:3e:67:97:7a:32:dc:c8:eb:4c:29:46: 77:99:d6:da:45:e6:7b:8c:45:6d:b5:29:6b:fd:98:a2:89:8d: 0c:30:42:f5:0b:7c:97:c5:b1:1d:e2:da:67:a9:48:a4:9e:29: f4:60:3f:4d:1d:48:83:82:38:ef:fa:cb:1d:86:11:a1:15:94: fb:d5:ee:68:f9:44:b9:3d:54:70:f3:be:17:8d:d7:2e:85:2d: Van Geest, et al. 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Expires 26 January 2025 [Page 20] Internet-Draft HSS and XMSS for X.509 July 2024 d9:1b:4e:d9:31:43:38:3b:88:12:84:d8:2a:38:b1:ce:0f:c7: 07:d4:63:2d:97:89:1c:b3:44:99:eb:d4:df:32:74:be:0d:63: 11:22:fd:fa:8e:e2:0b:56:12:56:0c:46:16:ad:44:10:26:98: dc:cf:c9:95:67:3e:11:c1:76:fa:b8:12:ea:96:f6:d9:91:ac: bf:49:b9:1c:8e:15:05:53:ac:9e:04:d2:5b:b8:87:bf:81:50: f7:02:a4:c0:9c:18:0f:45:ac:7a:82:cf:46:15:42:40:09:32: 89:a5:ea:90:a5:99:68:f9:93:0c:7b:d6:7a:a8:e9:51:e2:90: 9e:b9:ed:21:db:d9:7e:de:dc:62:6b:44:6b:9f:81:c5:77:39: 8e:1d:78:30:de:dc:53:80:e0:c3:fa:fa:94:68:28:91:98:86: ff:86:04:a9:bd:58:7c:31:37:1f:db:9a:29:f3:c1:48:10:20: 71:5f:fc:35:13:eb:7b:12:e2:7d:1c:cc:97:fe:8f:5c:a2:dd: f6:d2:a3:b2:ea:51:b3:ef:b1:1e:79:0b:00:53:f4:f2:52:75: 5a:d7:17:c5:31:a0:54:4e:2b:28:2c:4f:6b:7a:27:3a:2c:04: da:b3:1d:04:4e:a4:4e:94:5c:a8:91:70:ab:c0:4b:75:9f:b3: 6a:a9:4e:8a:22:e9:7f:fd:ec:53:e7:6a:6d:32:0b:8b:ab:4c: e7:7d:72:ec:04:62:1c:1a:45:1e:33:8e:37:ae:6a:2f:c8:fb: f3:69:ed:11:01:f3:f4:57:e9:29:d5:3b:0c:9c:0c:c4:cb:c3: 38:5c:01:e7:d6:31:c3:d8:ce:24:d7:be:71:9b:c8:96:13:ca: 5c:5d:e4:92:40:af:86:a0:4b:ff:a7:55:39:70:fd:ac:0a:e1: 87:c7:01:4b:c3:41:36:c6:c6:33:8f:4f:25:4a:8d:70:92:ac: 7c:95:cc:49:a9:dc:d6:6a:67:52:a5:5b:7f:2f:bb:91:e3:be: d6:28:fc:22:d0:72:66:e8:09:73:a7:23:c6:a6:89:38:0b:e5: d0:b3:f1:40:38:9c:4d:17:96:11:17:44:ef:e3:94:51:91:4c: 5d:fe:d9:ed:c3:76:a0:2d:3b:dc:8d:b9:31:15:f6:75:58:74: 2f:57:b4:29:21:29:6d:5f:eb:06:71:0a:f4:db:ff:c6:2f:16: 73:a7:76:6b:d0:5b:a7:21:5c:fd:f0:11:e8:6f:9b:d0:c9:c9: fe:35:76:4a:4a:63:9b:ba:48:ac:af:4f:91:67:9c:5c:47:d8: e3:2d:03:12:5e:f1:cb:56:34:75:69:95:ad:68:96:6c:e7:4a: 91:72:fb:9b:ba:e8:92:56:fb:9a:5b:5d:3b:9d:d3:c5:c4:52: 42:1b:f9:4a:47:42:dd:77:49:da:2b:bd:d7:94:5f:7b:b8:64: b9:06:32:7c:ea:d1:36:f6:95:b8:57:41:1b:6e:66:31:2c:ee: 87:7a:5c:19:2f:d8:95:4a:16:93:48:f3:97:25:3d:24:61:1e: d0:63:37:ee:3a:c9:a3:46:c5:94:a0:7e:24:cc:7f:72:8d:14: 9e:3c:33:ec:cd:9a:dd:b5:08:90:98:19:95:85:38:ff:ff:d2: 1e:bf:a6:c4:97:13:2b:3d:47:e9:57:59:d3:7d:99:01:6e:53: 4d:c0:82:97:fb:89:d6:7c:b7:23:0e:7d:6e:23:88:53:06:8f: 16:ff:40:0a:1b:cd:d5:1e:91:01:3e:77:3a:5f:c1:57:3a:7b: c6:d5:51:d7:e2:ec:89:12:6b:9d:03:e4:9d:bb:7d:4e:02:bf: 67:8d:03:ca:90:56:f0:9a:97:4b:02:2d:4c:31:89:82:76:97: fe:2f:d5:0a:3d:ea:0d:38:6c:30:75:5f:ae:91:53:d7:45:64: df:ba:0b:22:80:44:85:6d:0e:5c:29:7f:82:9e:54:a3:7a:95: be:96:79:66:9d:5b:a2:d6:2e:47:c6:99:7d:2b:32:dc:f2:b6: 02:91:6d:63:d4:93:45:60:c4:42:71:10:9e:fb:90:2f:e6:75: 71:ce:78:70:c1:da:ff:e1:47:fe:79:2b:8e:9a:81:bf:dd:02: e3:78:39:71:17:b3:23:14:11:9d:29:8e:21:a1:98:b0:ac:03: 5a:6c:9e:62:64:ef:4f:03:ca:37:a6:ed:e4:78:d5:0d:99:29: f5:5c:61:e6:48:cb:97:0e:5e:f9:2c:f6:b6:c7:7c:0c:a4:f7: 1a:f7:67:b5:5c:03:bf:bf:7a:e2:4d:a2:9b:5d:5d:5f:51:d0: Van Geest, et al. Expires 26 January 2025 [Page 21] Internet-Draft HSS and XMSS for X.509 July 2024 d6:52:8f:2a:20:68:08:bb:f0:9c:05:0e:ef:b3:49:0c:2a:1d: 8f:f9:03:b7:61:09:71:88:7d:e2:8c:e4:b8:ac:98:1b:c3:80: 55:a1:6b:dd:13:a2:29:4f:93:93:d3:d5:01:31:3f:7b:39:0e: 3a:57:6c:eb:5c:6a:5f:1b:ad:97:bd:97:23:18:91:05:0e:2b: b4:b1:11:ee:f8:58:c7:08:d0:de:a2:3e:ba:54:8d:3d:63:da: 91:50:3a:24:8d:19:18:23:2e:cf:30:8d:5d:e3:e7:02:93:fa: c8:f8:ea:05:e6:eb:06:80:90:4d:15:58:3d:26:98:13:4b:b0: ac:dd:90:2e:d0:e1:eb:71:32:83:5d:2a:a9:b9:b5:24:fc:e9: ec:18:ca:c9:a1:05:59:3e:fa:af:ed:4e:86:b1:fe:40:47:9b: 42:77:af:9c:2b:a0:e2:3e:fd:51:ab:02:77:e8:f1:39:45:aa: 54:b6:14:d4:14:20:fc:36:81:e6:04:98:8a:a0:c0:8a:cf:ae: f6:b5:dc:b7:eb:26:86:d3:cf:1c:38:65:54:04:b1:b5:09:48: f5:2d:07:ba:f8:eb:49:bd:d9:b1:54:ea:ac:c2:0d:20:10:79: c1:cb:e9:dc:2d:ff:55:50:4f:f6:05:02:78:31:33:6f:15:7e: 24:5a:66:23:70:b3:b2:0c:17:39:ce:15:38:c5:ff:60:16:38: 60:74:72:c9:70:d8:59:b7:80:7f:da:f6:67:3f:d0:ba:be:1b: a1:87:da:92:2d:a3:6c:99:29:57:aa:cb:d1:8d:66:f1:2d:c9: 56:60:24:56:4b:19:9f:f5:65:84:89:86:7d:4d:8b:f8:5b:60: dd:af:2d:66:76:6c:66:d9:c6:f5:39:25:6c:e5:7b:43:97:64: 5c:c5:20:1e:3d:b5:dc:92:b2:9c:d8:1b:1b:e0:bc:44:7b:9c: 95:c5:53:48:91:b2:a5:46:16:bf:50:af:a5:44:cc:54:78:3f: ed:20:d8:2e:0b:41:3d:f1:04:9d:df:3c:4a:d7:81:04:ff:8c: b7:79:f8:51:8d:b7:2e:ac:2c:54:e6:fc:43:76:8e:f9:be:8c: b8:5c:ad:c4:13:af:b0:6e:3b:d1:82:57:1e:f5:52:84:ca:cc: d2:68:f3:2d:04:ff:27:0a:e6:a2:fa:c0:a9:97:d6:64:45:18: 5c:6f:9e:c1:64:22:66:db:56:02:c3:a8:57:fc:87:1b:5c:43: 15:8e:58:fc:f2:00:0b:4f:6a:4b:a0:5c:da:f2:e5:1b:82:4a: 6b:ef:db:63:d7:7d:93:1d:2f:20:78:37:17:22:82:cd:6b:c1: 83:61:05:81:99:0c:25:29:d6:5f:22:bc:06:67:7d:67 -----BEGIN CERTIFICATE----- MIILSDCCAW+gAwIBAgIUVH5kcCmeA8V6pVx40SeHjFQ1F10wCgYIKwYBBQUHBiIw NTELMAkGA1UEBhMCRlIxDjAMBgNVBAcMBVBhcmlzMRYwFAYDVQQKDA1Cb2d1cyBY TVNTIENBMB4XDTI0MDcxMDA4MjcyNFoXDTM0MDcwODA4MjcyNFowNTELMAkGA1UE BhMCRlIxDjAMBgNVBAcMBVBhcmlzMRYwFAYDVQQKDA1Cb2d1cyBYTVNTIENBMFMw CgYIKwYBBQUHBiIDRQAAAAABK+u/ZhTeb5ZbTSpQAHutXCKwE3lyAhSpX/yW4Jt4 jta+jBxwPNjdeLIaFEe+Hw10cj82dsLLGa0pkAuC3pt/36NjMGEwHQYDVR0OBBYE FGLONaVHd/8hhy68LSfnjvQ1a8/YMB8GA1UdIwQYMBaAFGLONaVHd/8hhy68LSfn jvQ1a8/YMA8GA1UdEwEB/wQFMAMBAf8wDgYDVR0PAQH/BAQDAgEGMAoGCCsGAQUF BwYiA4IJxQAAAAAA5YiouHOtTZL4XIHFimNXaqc7VKq2BorZ8cILyCceS6LP4tpE 6ujyQKi5VJxJNhIk33St5SnvT9qIDSFdO2RjJ9CEtZV6MBg3zTQX3aydnkjbdAd5 hCFa8CbNIWR7dzNIWGebLLKFbczsMUsvUVU6heHKBBXObkc59ekxRUHtccZPlvWu ZGq9ctCMFwKZEB0UNMrlR+P3ZpaWEdWXdnaD8YSltgBePmeXejLcyOtMKUZ3mdba ReZ7jEVttSlr/ZiiiY0MMEL1C3yXxbEd4tpnqUiknin0YD9NHUiDgjjv+ssdhhGh FZT71e5o+US5PVRw874XjdcuhS1c0KDFmVLMeeccGNluPQ9sBVEzKDXiAllfH+14 CsZi8H3+c5YDTLRC4wDC18vrURDEDGS4N/6F0I4RbaYWd7EeAdke8xCc3QG8OHVe j1ieW2x7CkEIWTWpOoMZ4H2h9c+jHE4H4a0DlfLTi3kz+FIiUxseMpphP8R8mujV tSjxhGXVwfxNFpOIk2nK+pSglU4jrh5g4Oi0v/8WlXEPMXS7vrha6ySVi5UoE83j Van Geest, et al. Expires 26 January 2025 [Page 22] Internet-Draft HSS and XMSS for X.509 July 2024 qWX39W6bqal6Bc6r8FRi2RL4oRpo368Vj4rfZyfJ7b3hgaaNmoTzkTbZiXSO74Tc XAMaCOTX8HL8bYoBNJTl/whRG4Bf5wfYnyXkHcP45dCcUM9mcfnM98Cn0GYBtxeg X2aXpP9irBygYw0wKOmQ1VmkSNgHhwJLP2gjpQTcs9dF9tyw7MaQphyh+H6EumN+ WmQUeFj1dcD14R29SVfAQAgHmX9DLuIl2O2jGuN48XivAklUNlmO03KlC1IyvRei z+FHISg9urYk2Rj5RHM17SmkGLztaM1KmjTLGi+zX7pzmxjueqiSJWUlgQRjHCIr uLqBIbz5nah4mHW87UrGt2/AkSTrHfld4ON4TgX2NA97QVRJIKIwZpTx2sFsP14Q kpKjDH7oiyYRHNdoyTF5s6TVYwBow+OGLQmSSy1jfbgDpExgtCwS1QufFijqiC+7 HBkLD0A9Z+gL+sbjOUSyvYo/Id2q7KOMSN1MmUOG10iBa+W5u1mfHA8/Efd8S2eo lcJ8yztmsHmmVW9tsCmKXnvuMGjz3UEpkfZ5ca6NIXB4HV3S98/nQjjRjFKmpvax OLErI4HhHyFtmT8Q67Gpc7g+MZnM3SvfWCfbC1opmY+xn+kxQtAm21O3fjBBlcPw B4O7sGO1FkjypmAvMl0iodp2TjcmUw2Vey25BS+TK9TfwQJb96WiTxFcgPTwvcfq PNtv4utsf8NY2TF3S033zrvWyGSjAdX5pI3o8O4JBiwLPKwKV9jkgXnqSr1RA4hM 0EwLxAx+LeffG2diwNGcrbvT8HXdg6pwmSwZeD0mK0dvJMFgAh5LdQSRHwgcs3mg m9v7XT/H4wkfQT5ku60ZPTXhpvRpC6IEN0KVxsfl9FYOZ1t4NLsH8Y/nc1uH19/J LY2MQnaHFYVLIwMgNOEb9gwehFPZG07ZMUM4O4gShNgqOLHOD8cH1GMtl4kcs0SZ 69TfMnS+DWMRIv36juILVhJWDEYWrUQQJpjcz8mVZz4RwXb6uBLqlvbZkay/Sbkc jhUFU6yeBNJbuIe/gVD3AqTAnBgPRax6gs9GFUJACTKJpeqQpZlo+ZMMe9Z6qOlR 4pCeue0h29l+3txia0Rrn4HFdzmOHXgw3txTgODD+vqUaCiRmIb/hgSpvVh8MTcf 25op88FIECBxX/w1E+t7EuJ9HMyX/o9cot320qOy6lGz77EeeQsAU/TyUnVa1xfF MaBUTisoLE9reic6LATasx0ETqROlFyokXCrwEt1n7NqqU6KIul//exT52ptMguL q0znfXLsBGIcGkUeM443rmovyPvzae0RAfP0V+kp1TsMnAzEy8M4XAHn1jHD2M4k 175xm8iWE8pcXeSSQK+GoEv/p1U5cP2sCuGHxwFLw0E2xsYzj08lSo1wkqx8lcxJ qdzWamdSpVt/L7uR477WKPwi0HJm6AlzpyPGpok4C+XQs/FAOJxNF5YRF0Tv45RR kUxd/tntw3agLTvcjbkxFfZ1WHQvV7QpISltX+sGcQr02//GLxZzp3Zr0FunIVz9 8BHob5vQycn+NXZKSmObukisr0+RZ5xcR9jjLQMSXvHLVjR1aZWtaJZs50qRcvub uuiSVvuaW107ndPFxFJCG/lKR0Ldd0naK73XlF97uGS5BjJ86tE29pW4V0EbbmYx LO6HelwZL9iVShaTSPOXJT0kYR7QYzfuOsmjRsWUoH4kzH9yjRSePDPszZrdtQiQ mBmVhTj//9Iev6bElxMrPUfpV1nTfZkBblNNwIKX+4nWfLcjDn1uI4hTBo8W/0AK G83VHpEBPnc6X8FXOnvG1VHX4uyJEmudA+Sdu31OAr9njQPKkFbwmpdLAi1MMYmC dpf+L9UKPeoNOGwwdV+ukVPXRWTfugsigESFbQ5cKX+CnlSjepW+lnlmnVui1i5H xpl9KzLc8rYCkW1j1JNFYMRCcRCe+5Av5nVxznhwwdr/4Uf+eSuOmoG/3QLjeDlx F7MjFBGdKY4hoZiwrANabJ5iZO9PA8o3pu3keNUNmSn1XGHmSMuXDl75LPa2x3wM pPca92e1XAO/v3riTaKbXV1fUdDWUo8qIGgIu/CcBQ7vs0kMKh2P+QO3YQlxiH3i jOS4rJgbw4BVoWvdE6IpT5OT09UBMT97OQ46V2zrXGpfG62XvZcjGJEFDiu0sRHu +FjHCNDeoj66VI09Y9qRUDokjRkYIy7PMI1d4+cCk/rI+OoF5usGgJBNFVg9JpgT S7Cs3ZAu0OHrcTKDXSqpubUk/OnsGMrJoQVZPvqv7U6Gsf5AR5tCd6+cK6DiPv1R qwJ36PE5RapUthTUFCD8NoHmBJiKoMCKz672tdy36yaG088cOGVUBLG1CUj1LQe6 +OtJvdmxVOqswg0gEHnBy+ncLf9VUE/2BQJ4MTNvFX4kWmYjcLOyDBc5zhU4xf9g FjhgdHLJcNhZt4B/2vZnP9C6vhuhh9qSLaNsmSlXqsvRjWbxLclWYCRWSxmf9WWE iYZ9TYv4W2Ddry1mdmxm2cb1OSVs5XtDl2RcxSAePbXckrKc2Bsb4LxEe5yVxVNI kbKlRha/UK+lRMxUeD/tINguC0E98QSd3zxK14EE/4y3efhRjbcurCxU5vxDdo75 voy4XK3EE6+wbjvRglce9VKEyszSaPMtBP8nCuai+sCpl9ZkRRhcb57BZCJm21YC w6hX/IcbXEMVjlj88gALT2pLoFza8uUbgkpr79tj132THS8geDcXIoLNa8GDYQWB mQwlKdZfIrwGZ31n -----END CERTIFICATE----- Van Geest, et al. Expires 26 January 2025 [Page 23] Internet-Draft HSS and XMSS for X.509 July 2024 Appendix C. XMSS^MT X.509 v3 Certificate Example This section shows a self-signed X.509 v3 certificate using XMSS^MT. Certificate: Data: Version: 3 (0x2) Serial Number: 5c:22:ad:8a:06:51:9e:67:02:6a:2d:43:3e:8b:c7:23: 43:77:80:c8 Signature Algorithm: xmssmt Issuer: C = FR, L = Paris, O = Bogus XMSSMT CA Validity Not Before: Jul 10 08:28:04 2024 GMT Not After : Jul 8 08:28:04 2034 GMT Subject: C = FR, L = Paris, O = Bogus XMSSMT CA Subject Public Key Info: Public Key Algorithm: xmssmt xmssmt public key: PQ key material: 00:00:00:01:4b:a7:89:11:6f:fc:1d:fb:d3:e7:71: 73:b8:a2:48:ef:53:b9:9d:1f:c6:8a:7c:be:4f:8a: 29:fa:41:fd:bd:da:20:7f:f6:3b:b0:c5:b8:a7:c2: f2:5a:f2:26:14:eb:36:f0:26:2f:87:74:fb:0e:d5: 7e:17:a0:d1:4d:b6:cf:51 X509v3 extensions: X509v3 Subject Key Identifier: 7C:7D:59:B8:95:61:D5:03:6A:1E:3D:F1:24:AB:1D:ED: 04:CD:DB:5F X509v3 Authority Key Identifier: 7C:7D:59:B8:95:61:D5:03:6A:1E:3D:F1:24:AB:1D:ED: 04:CD:DB:5F X509v3 Basic Constraints: critical CA:TRUE X509v3 Key Usage: critical Certificate Sign, CRL Sign Signature Algorithm: xmssmt Signature Value: 00:00:00:57:c4:98:89:ff:d9:0a:8e:6e:6f:16:95:8c:ec:35: 42:21:c2:ca:56:ed:f8:81:f1:b2:4f:2b:6d:73:f4:37:55:fc: f4:4e:15:eb:6b:90:de:34:fe:d6:96:70:94:8d:c1:e7:4a:32: 49:30:3a:40:a4:67:d2:fb:da:f8:d8:a1:7a:48:22:1c:e3:98: bc:d0:68:85:29:c9:e5:f7:5c:56:d8:9c:80:be:68:ed:11:eb: 39:0f:ef:cb:09:b2:28:30:a6:2b:05:bc:de:11:22:be:c4:dc: 08:9a:3d:b4:49:37:1f:54:5e:5f:2d:93:62:b0:95:c5:5d:23: 92:f3:55:40:78:19:00:56:9e:a2:f1:0e:4b:ae:75:d6:92:09: b1:79:ec:c9:18:67:19:09:86:83:74:5d:0a:06:ab:da:f0:af: 02:97:4d:d7:73:06:8b:a2:84:c7:09:af:dd:8b:15:39:e4:30: Van Geest, et al. 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Expires 26 January 2025 [Page 29] Internet-Draft HSS and XMSS for X.509 July 2024 c4:63:30:f3:78:05:a6:ab:0c:e7:33:a0:88:f7:e2:e3:4a:1b: fd:66:3c:14:be:ee:20:d1:32:95:db:97:ff:d9:c2:bc:7a:c8: e4:ba:24:c5:b2:2e:16:f8:53:af:b4:57:56:25:26:f5:36:48: eb:0c:20:f9:3b:73:ff:dd:bd:20:81:0c:f5:55:89:7d:46:1b: 05:b6:25:df:96:99:ea:09:79:60:72:d8:37:92:a8:f1:75:a3: 5c:6d:54:b7:f3:32:17:35:1a:2d:96:e5:5e:fc:cd:54:30:49: af:6f:1a:42:d9:98:52:72:73:74:72:b7:72:95:80:1d:31:5a: e4:83:b7:b6:d4:14:00:0b:59:ce:7c:bc:1d:72:24:ab:74:d6: 2c:9c:20:b1:0a:78:6f:a9:76:8d:6c:37:02:35:bd:6f:99:ee: d1:45:36:f1:34:60:7a:12:57:27:68:05:26:14:75:3c:9f:0d: 3e:b7:5d:b8:2a:6c:1d:a7:b0:41:c4:f4:3d:ae:8e:51:54:37: 65:ad:0a:c9:28:a0:3f:04:ed:54:59:c4:9f:1d:3d:70:97:5f: f9:44:53:ff:15:9f:03:13:7b:41:6b:c0:f7:8f:a3:27:2b:03: 39:37:8f:bd:91:65:4d:74:a9:9f:45:6a:a4:25:dc:4c:f9:7e: 59:fc:4e:93:7c:89:8f:71:8e:a6:99:66:5e:6a:25:a4:c0:a6: fa:25:f7:68:5c:8a:02:f5:7b:49:cd:89:e1:77:78:95:1b:a9: 21:78:6e:f4:7a:e2:04:e5:0e:21:52:bf:04:cd:0c:69:5d:d7: f2:57:71:9f:d8:01:e0:f3:10:cc:15:2d:fd:99:78:ff:dc:1f: 8f:a9:31:0d:0f:9f:f4:2c:a1:3d:4f:b2:51:92:68:f0:ec:d8: 5f:c4:55:a1:4c:c8:12:e9:05:7e:05:93:5f:f9:76:99:85:18: 29:24:60:14:5d:b3:79:f9:4b:7c:e4:22:71:8a:c2:66:45:d2: 41:14:5d:59:4c:0a:b5:2b:ab:bd:c6:50:f8:87:37:42:e6:d4: 96:72:cf:45:f0:d4:bf:0d:c5:17:9f:f1:b9:12:5c:a8:74:89: 9e:56:07:cf:8f:98:9a:da:d7:db:7f:c7:d0:3a:0a:14:cd:5a: 66:0c:eb:02:76:a0:d4:56:e6:e8:be:a1:f0:c7:23:b3:4f:86: 90:1a:5a:16:8e:07:0d:24:d1:ee:03:98:9f -----BEGIN CERTIFICATE----- MIIU6zCCAXOgAwIBAgIUXCKtigZRnmcCai1DPovHI0N3gMgwCgYIKwYBBQUHBiMw NzELMAkGA1UEBhMCRlIxDjAMBgNVBAcMBVBhcmlzMRgwFgYDVQQKDA9Cb2d1cyBY TVNTTVQgQ0EwHhcNMjQwNzEwMDgyODA0WhcNMzQwNzA4MDgyODA0WjA3MQswCQYD VQQGEwJGUjEOMAwGA1UEBwwFUGFyaXMxGDAWBgNVBAoMD0JvZ3VzIFhNU1NNVCBD QTBTMAoGCCsGAQUFBwYjA0UAAAAAAUuniRFv/B370+dxc7iiSO9TuZ0fxop8vk+K KfpB/b3aIH/2O7DFuKfC8lryJhTrNvAmL4d0+w7Vfheg0U22z1GjYzBhMB0GA1Ud DgQWBBR8fVm4lWHVA2oePfEkqx3tBM3bXzAfBgNVHSMEGDAWgBR8fVm4lWHVA2oe PfEkqx3tBM3bXzAPBgNVHRMBAf8EBTADAQH/MA4GA1UdDwEB/wQEAwIBBjAKBggr BgEFBQcGIwOCE2QAAAAAV8SYif/ZCo5ubxaVjOw1QiHCylbt+IHxsk8rbXP0N1X8 9E4V62uQ3jT+1pZwlI3B50oySTA6QKRn0vva+NihekgiHOOYvNBohSnJ5fdcVtic gL5o7RHrOQ/vywmyKDCmKwW83hEivsTcCJo9tEk3H1ReXy2TYrCVxV0jkvNVQHgZ AFaeovEOS6511pIJsXnsyRhnGQmGg3RdCgar2vCvApdN13MGi6KExwmv3YsVOeQw n8kAJagzTd7oJbY1C1G/ejSn6ITo+jlbqjdulYmsJkpOyr4pCEs8KKeFaq1a0pPr EuGahxxAO88VbENOiCFUUn4NbRcpjRVv70JaqSXQl4BhMSKknyUXUa0LocuTtPWm sCIbbVBkKki9BRaIAON7VtADs3otagvz3qKMboGALI/p2HjtW5nJE9G263jDQCuh eoQKuhKHXh04JCKPwKNlHBzOLY7lLx++k1z+HM2onX5+zxjinMVU3GJhdCNVZGYh lkynLoqUpjUQpehebpGsqMvtUStmRQP1h+1NjE5tVIChM4qEnSMxkMYFEaedvVEK c0e8CEkRs5j/ARRp18CgDFXkXuL6hKwns4UsmXFSnDP4nYzSE7xuGHkVpwLuFesn 2K8kOAKcyjDz4jBBL2KiLKWBG3FtsZS9xj2eXlFF3lv01+Y159h81Zjsfg74ncGn e7NlsaFLLezZEkVrHwscazsKZnY59Myb4bcX91P8w6YY9y5FUrEYmXXRabt3yBqE Van Geest, et al. Expires 26 January 2025 [Page 30] Internet-Draft HSS and XMSS for X.509 July 2024 Xwa1i8sCsLIPvxcYZT2ncltxn5J+Ot+EzGVcxFtw/cw4nhJu+f8fAvzK9WiG/Mpx 8T17MrTUw6IgFj8SB3GVO9SxHvyMHzSMyKuMu3WTwRrShT6a5gSGiN4nRsrz9/OO VBjqqq4UArFKauAkd0AojTcnnIdqgQnSAU0gf96EqICMjmOCvmbfhzBcuHEK6ZFo cW6Xl/AnTvquaoWsgM04SEnBK53bVMXwv/oG6JY6wJXwiL2OgHg93K1dClbdx4Cf /GRYTW0n9tcajLIcCep9T3SZDUoMuLDvdN1vb9zlg+HjwuhYF7hEii3s31T2H2ei s8UZ+7nHGzzqvSzhQ2XRWhfck53FhQxVNBNJFZLiUhTRgapiAhq6ybBThY570U40 dqx517NIkr9Vfi1czTKbwUGno823lFyWHj4nTevwYUuk4zy7aYU36ZyY9Gh6YXeM vbkw1vH9aXg/lpl7aTmQs3y2iO3NGdpCZOUyTKIw98ToJ5Nw7fpeyo560ROvFbFZ yZuRYQsG1cwugLtJk92+U4i+r4BkfF6+e4vnXzmvq2dCawaq79Zpr6kAH6AVEAQ+ 25OyN9vrhVlDoo2PBozLoh2oPJ/0pHzIzf/wqHkP59iUZ+wXP/puBAdPv4YEbPxG h7UQhaQH6K+p7F0oXICMMczHs4EXC0t9HJ50Ah7v3g0bwcAETUb93AukxjPmhQpg OU0L+UlEM+AVmRm/x4rGlgSTN2td6L5z1IC4gQ+akUTPcgLTyfjgfdKbK//rQm44 ftzNp5DFLCugIze5ZBCmJ2hHxfHojUHBSeg1SM7ICEyt8q1d6WLryTxhhRjGNHP9 JqTwUIObZFSqVWzYoiGB/5wnOR/Dog7lU7HX+h/vKYvCkJjqLt1Fv8Nso5NHmQMY Jeil7i5363/0SUlZmMH8qx6tIL34JP0hG9paB1XIUAUxUJOy+G7bc01fNKrzNIOQ 8EFtyENW0XUH9RYgs5myxzQlxA50WlEPezt/aqlBF7VHYi1PuWGXYOmuyq0xbksK R5xTZqNOw5Z8AaCOroNFQuaSEo6Xb+igt32mdCSqILD6npjofLTaMOmUCJa3uVNP dV8MTYLjz268+iNP+jMXfJi2HkeJPtmhqkIZJa6eP1NErJGW2FXDQB36rYY4Yr0n LyY0vq2aAURCyFSlOukK//hBbTge4j0IOpRPHmDQscKOlDTwMD7wkSXumDS0jZVO z+0dYYnJWRBo8rwuXL3ADx2cL3zAJyUUm96jdGQoFCyispA6pGpQ6Y7KeOW2dFbg kml9tC7g52aSFpKgw9tP09BXTUoo7rfMBO8X2fwBux6yWwI9H1qFc6GBlrczXXnl a8kpczQBaepX8AG+TvNc8wqnNwitGJzHTFnQXbsB8VN2y83ZhF68IhF2AdnjrxcD Ae84TK3BfanGYSu6nIGVhq+7c5Dc2S/RP5VquUYP+4RkfH2GZaoQcVYZX2BSfxn6 1VrgkOS5YlVxKmH5Ny9eB3FDzwbKatVSyDPhrbI+pGEBALxVXQrz5k81BsSoP0yL m8lBS/TBV+48wERoUlotuafyQdrEjX3bQLb8R2NaaaHHjMw/r1GUN5VYgnnSFkq/ EgtZpaURceYcYzvq8C8Q4JeaoQRT0HL0PHc7eO61qmv1u1zpNU9pZYcpJOxHe3ha p8Hl8XN9TXnv7051h9uPNv1QPnTcF9TDP0+CJFEbEhYmYduTFRk5VfUFLG6F3bLM T8AJCnZG2OTyEZKh4DaoJcdFGWyY65r6weyAGM7R+MQjmvm4HwVnjkXL5u4L+ttn H2IsSXi7VZgeM0Jj8tvuc/dggG1fmuiMiTlbsoTiw5l3818Z7LgrzmBZLGYG+cFD uf2UNZ4onaCO/Q3GGrsgk7BjaoMvCtvCs46x3fWrGQlTettyPx4lB+safSHaiCLm 8LqzFW+V83LSy21IuLp7qkB/gf66FcJ3nYZYvH2JLns6lgSf8TpQSFolTZG27d72 Lk3ldxFtdvQjX5HwD3lZevMyJBHEiDAhJjvxeQ8EBq2CbepYTqpOCn97XKWr3nap qcfZ4+vWhIACq9pMW0mQKcXLWxwGYeiaz6TqnTEWaiE62SIluDmdTOOGdqjd2LTb iPleYcMdh9+pMTN6s1A+8s2toJ2YX2zi8NgnucI3f420+IQTXyJtm4G9HOV1rrWV 0cvQxuN47IxxbYxdQHl9WD1cY3fMLqJjqXEwL1kq7IKx5bnWv/sh5pf8cEWax+jS gXOx9bx2yrS+nzm1LfI+xTLjrjz9dKE2WlxN9t7S1WZhdIguS2l8KS/gKtbYk5lB vHt//MMchO0WwAh4+1dhnoN60em3rZqFHMO6o+QYtgD2NSfiJx0Q3EQdEQWi298K WZic88o6syYt0cQ8/CHzPDlif/S9kXTvAoPaSiJAYJ9qn4uP8eQemdUXVWIcYAF9 x0HbGZ4pAbqgX0HzYe2dDJzvMouwiomx5AbJL01CKgGEKazxQaChybSD2YcaUx9/ 1IUSLnnzLIgGc2LuFrzHi+cJlroCtVarb8DPdmRiDh615GlCTe1WltkdjQdAesW9 059DB+SdtiYrM2p52Yrs7lFz8ZGw6JBC2xFVVxsBEPwR/3e0CQFt+IzPchbfCRIJ vUnvM7nFjTVgd4CP7pgYvrs6YelbagmwCh44gOlxRnehGXrDBFeld+ZaAXfSkpD2 mVCHPzCKNz03HmsdpHE8axUHAfY9Q5aj9zDPCCwyo8pnblnaUS6WvJdBS3xfl6PP RiCeZJYI9wwDS7SDCdtsu5QjTv97+y+EZgqW+eFY/w08hGKca2CffjnPM/MDL8fQ i2/zmmLMM8S9tPy4gJ3+nsLw0J4Hcaj5H6dkTWP5a84+RAo/BViQDQwgfU7HUtDl t2HTalIIN5EVPM9B7O+IVtwUKhJVywUBI4nA/sreQNLQlqMfB0pYlvqy73iW8HMl yC4gO9gCz+fKsCkaJX8Vli39Urspw/y/sXzYD3YhBSguidmCDsvNAx/DcbQPdVLl tJOMrO3VMFq5M4T9PNrc5oRtwma+k61nf9vQCJVkWiwTf+IFtdzQv01uk8I7jDux Van Geest, et al. Expires 26 January 2025 [Page 31] Internet-Draft HSS and XMSS for X.509 July 2024 XDoo6MOW7VniYlKOlY214cHyNFu/Wszx7uw9bGGZ8sjkBV/q1XQ8/98bIL01MMAn +KRuc0WB4rkVUseg58j9e4730gzE6SJpTnBix4qipmF8C1p0jQ/A5WbcGHt0O3Kr GlOzSe9QqnaA5xFTkKsk0S78ZkHPs8yurPnrHhn3vFQAFtqw1Ct0xzX7CP9nFINa 62u3tGMo4ra41AwTaoy7MMH7bELfI8TwviXfKzkRu4LD5/kESHfP0F49bhl/s8Qv xOxRX53Hj4ifIXmNoBc+F3O09aJxcOaZxP1M8mNkIyLDcnFSQ0KlkONZd1D/oQku x/Z+F/Ki1n4sdfKrnjZ4q1e+xZFxcCy6A5GAl/SeFrz6gPQiKrV1FVfZsJKesTXb JpZ3KJyJmdubVdQpFV9Uig1YqJUTlRdsa7Aqo/oa7C60Dgjqj+GMWc99YADzv7fk XwimAu/O15yNb1bXyTXp5c/S9SjK5jbvxCZS1U0E7FBzh9xwHxrbB79M6exXmH+8 yDGefuY6tMR3kzlWV2cFhI0DAtm/BGv+cYq+toquRLDd2x9qJuVQ1f8Dgdgbnz+m vBtStUmTsCf9WdR9aeljNQub3qHUcAwIQUt21s3IZYy7mm7k8eIwE52jx2cWD329 rNyqnBcBpicU+krBJz8He58vR1bM8JY46Vh8H2xzEDwRaCo8X3T+N66L6evGBjBv YjxcbC3HWyRtzHU/19TmcmSKrQNnrc3LLXyCSanv6Lm+8myYQk4mRgRYpSvJiJuk kX8iCRJSKtFONiLYU7w4k60RGcXnyYMAtLawrJYyytAIaeTSKYZ0dEm+SrK/8i/C Uv0VPI0HEjqYx0lngR2xXej0Qnmg90S4lZ/hN0FbybGJkHtmluuO3BvXc7LrwUJB 6C0ounTqfHeHdls2ED2HCFKU5mCVwRvJJ8FCqjJi7cpvBE4ROj094Ng6wP+5mpSx efMBFDqZNFmO2azxqXe1LVnhKZYbE4CLEJQ+wlHbwSQGAkeWm65dJTSvS2Xziutl fKVefKLWHUEgEwte6mey679sRPt2MVhe0jNtb5w6QXA0EW+ZjEKd1isUebCs1N46 sNjSl4iaF2g+eaiwStenPGPFKcFldnR+wt64Sc4mX9JiLQ9czGxTwKR1BVLRUjiu chd8Amdrdjjncqo4cF6vopjAwXqgbeyQUY3VmYs5BWrrDIc3W0sAkSx9im3BIxBE JlpH93+PhhzCp5+eSPZCzdE82eiV3gA87Nuho8B/9xc7StzS9dSbEhkPbRM4cgYh 65SIh4+h3vbXoIiq40e7aegwWYLSOm3HJpWSpFgH69ul0btRACjvb8jOnA/ZjeCz FNuQ3fkmr7CISK4icSav1eBNXEHmC/Jcm7tpgglaWGO5DIoiN6qicSql2ad7n9X0 F429Tt4IaqQgzqaFx/oFx9gDdwzdQDIRQyqMUCJL+qHR8ZRCP9W4oN0BcW4wNP+m doDmwQSL8MM4FJiu6/0FmNGWfrS/Uc6qtGZxMJ96Rbbt0W6PsGyl9U/uvOplXiRD c0tQjshoDyNI7d3/hJebMQ27LNtpaww0cz6uadL1vqiZvntAgvT+NfU9o7G04mx5 twsprTA9Vp28JOnmpW3Mgxh71ZijX91xcilxRY9BUs6GmVzxQAwesZfaOhRKpwJI 2E5jEpnaKOneDReQOvXamgF8FRK/AEh9Y4yJC7l3lQEnsjNzS6uo8yTuwdMMo54m /iQjO4K0Gl5y3J6ROnuFZA0wLmtVU36iT7cQ5HehAUqy138clKan5Wbix+U3bYks crFTz9ZnD3f4vwcgmJlg7y5ywHKeeSrKove8gttT92jj7U84ZIMb3aV43NsIqTQ1 9vGcdoVezVmjyIlQW72gZAa019t64XVXE5DOBUug9iJwC3ighEaHtKcNiMZBxZPL dzfRrzdIuUfbmXqYNoLLJ2qa3oAkOinrq72wQA2mUOWkcqMZy/NSji8dEO99ChVs SQhTVYSFXHNTzj4Y5QSSppnbTXvHqZnOqpBIc3ph9ZJz2rQmdKE5dOOC+TLgCO+8 L59t4do98KVGtheVuGsTffOhMY23R6BFqiBT1vA866LneiaMxsfLDyFa30YGxbIt pTu3Af0PVRteWABwlKN/SI5KZ6QUXeC6tvmb595h2GeDrLcB62LFIrhIOpZV+xpK xGMw83gFpqsM5zOgiPfi40ob/WY8FL7uINEylduX/9nCvHrI5LokxbIuFvhTr7RX ViUm9TZI6wwg+Ttz/929IIEM9VWJfUYbBbYl35aZ6gl5YHLYN5Ko8XWjXG1Ut/My FzUaLZblXvzNVDBJr28aQtmYUnJzdHK3cpWAHTFa5IO3ttQUAAtZzny8HXIkq3TW LJwgsQp4b6l2jWw3AjW9b5nu0UU28TRgehJXJ2gFJhR1PJ8NPrdduCpsHaewQcT0 Pa6OUVQ3Za0KySigPwTtVFnEnx09cJdf+URT/xWfAxN7QWvA94+jJysDOTePvZFl TXSpn0VqpCXcTPl+WfxOk3yJj3GOpplmXmolpMCm+iX3aFyKAvV7Sc2J4Xd4lRup IXhu9HriBOUOIVK/BM0MaV3X8ldxn9gB4PMQzBUt/Zl4/9wfj6kxDQ+f9CyhPU+y UZJo8OzYX8RVoUzIEukFfgWTX/l2mYUYKSRgFF2zeflLfOQicYrCZkXSQRRdWUwK tSurvcZQ+Ic3QubUlnLPRfDUvw3FF5/xuRJcqHSJnlYHz4+YmtrX23/H0DoKFM1a ZgzrAnag1Fbm6L6h8Mcjs0+GkBpaFo4HDSTR7gOYnw== -----END CERTIFICATE----- Van Geest, et al. Expires 26 January 2025 [Page 32] Internet-Draft HSS and XMSS for X.509 July 2024 Acknowledgments Thanks for Russ Housley and Panos Kampanakis for helpful suggestions. This document uses a lot of text from similar documents [SP800208], ([RFC3279] and [RFC8410]) as well as [I-D.draft-ietf-lamps-rfc8708bis]. Thanks go to the authors of those documents. "Copying always makes things easier and less error prone" - [RFC8411]. Authors' Addresses Daniel Van Geest CryptoNext Security Email: daniel.vangeest@cryptonext-security.com Kaveh Bashiri BSI Email: kaveh.bashiri.ietf@gmail.com Scott Fluhrer Cisco Systems Email: sfluhrer@cisco.com Stefan Gazdag genua GmbH Email: ietf@gazdag.de Stavros Kousidis BSI Email: kousidis.ietf@gmail.com Van Geest, et al. Expires 26 January 2025 [Page 33]