<?xml version='1.0'encoding='utf-8'?>encoding='UTF-8'?> <!DOCTYPE rfc [ <!ENTITY nbsp " "> <!ENTITY zwsp "​"> <!ENTITY nbhy "‑"> <!ENTITY wj "⁠"> ]> <rfc xmlns:xi="http://www.w3.org/2001/XInclude" version="3" category="std" consensus="true" docName="draft-ietf-lamps-rfc8708bis-03" number="" ipr="trust200902" updates="" obsoletes="8708" sortRefs="true" submissionType="IETF" symRefs="true" tocDepth="3" tocInclude="true" xml:lang="en"> <front> <title abbrev="Use of the HSS/LMS Hash-Based Signature">Use of the HSS/LMS Hash-Based Signature Algorithm in the Cryptographic Message Syntax (CMS)</title> <seriesInfo name="RFC" value="9708"/> <author fullname="Russ Housley" initials="R." surname="Housley"> <organization abbrev="Vigil Security" showOnFrontPage="true">Vigil Security, LLC</organization> <address> <postal> <street>516 Dranesville Road</street> <city>Herndon</city> <region>VA</region> <code>20170</code> <country>United States of America</country> </postal> <email>housley@vigilsec.com</email> </address> </author> <dateday="19" month="09"month="December" year="2024"/><workgroup>LAMPS Working Group</workgroup><area>SEC</area> <workgroup>lamps</workgroup> <!-- [rfced] Please insert any keywords (beyond those that appear in the title) for use on https://www.rfc-editor.org/search. The ones from RFC 8708 are "digital signature, message content".--> <keyword>example</keyword> <abstract> <t> This document specifies the conventions for using the Hierarchical Signature System (HSS) / Leighton-Micali Signature (LMS) hash-based signature algorithm with the Cryptographic Message Syntax (CMS). In addition, the algorithm identifier and public key syntax are provided. The HSS/LMS algorithm is one form of hash-based digital signature; it is described in RFC 8554. This document obsoletes RFC 8708.</t> </abstract> </front> <middle> <section anchor="intro"> <name>Introduction</name> <t> This document specifies the conventions for using the Hierarchical Signature System (HSS) / Leighton-Micali Signature (LMS) hash-based signature algorithm with the Cryptographic Message Syntax (CMS) <xreftarget="RFC5652" derivedContent="CMS"/>target="RFC5652"/> signed-data content type. 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 hash-based digital signature, and it is described in <xreftarget="RFC8554" derivedContent="HASHSIG"/>.target="RFC8554"/>. The HSS/LMS signature algorithm can only be used for a fixed number of signing operations with a given private key, and 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 are defined in <xref target="RFC8554"derivedContent="HASHSIG"/>./>. Currently, parameter sets are defined that use SHA-256 <xref target="SHS"derivedContent="SHS"/>/> and SHAKE256 <xref target="SHA3"derivedContent="SHA3"/>.</t>/>.</t> <section> <name>ASN.1</name> <t> CMS values are generated using ASN.1 <xref target="ASN1-B"derivedContent="ASN1-B"/>,/>, using the Basic Encoding Rules (BER) and the Distinguished Encoding Rules (DER) <xref target="ASN1-E"derivedContent="ASN1-E"/>.</t>/>.</t> </section> <section> <name>Terminology</name> <t> The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>", "<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are to be interpreted as described inBCP 14BCP 14 <xreftarget="RFC2119" derivedContent="RFC2119"/>target="RFC2119"/> <xreftarget="RFC8174" derivedContent="RFC8174"/>target="RFC8174"/> when, and only when, they appear in all capitals, as shownhere.</t>here. </t> </section> <section> <name>Motivation</name> <t> Advances in cryptanalysis <xref target="BH2013"derivedContent="BH2013"/>/> and progress in the development of quantum computers <xreftarget="NAS2019" derivedContent="NAS2019"/>target="NAS2019"/> pose a future threat to widely deployed digital signature algorithms. As a result, there is a need to prepare for a day when cryptosystems such as RSA and DSA that depend on discrete logarithms and factoring cannot be depended upon.</t> <!--[rfced] May this be rephrased to avoid repetition of 'depend'? Original: As a result, there is a need to prepare for a day when cryptosystems such as RSA and DSA that depend on discrete logarithms and factoring cannot be depended upon. Perhaps: As a result, there is a need to prepare for a day when cryptosystems such as RSA and DSA that use discrete logarithms and factoring cannot be depended upon. --> <t> If cryptographically relevant quantum computers (CRQCs) are ever built,these computersthey will be able to break many of the public key cryptosystems currently in use. A post-quantum cryptosystem <xref target="PQC"derivedContent="PQC"/>/> is a system that is secure against quantum computers that have more than a trivial number of quantum bits (qubits). It is open to conjecture when it will be feasible to build such computers; however, RSA, DSA, Elliptic Curve Digital Signature Algorithm (ECDSA), and Edwards-curve Digital Signature Algorithm (EdDSA) are all vulnerable if CRQCs are ever developed.</t> <t> Since the HSS/LMS signature algorithm does not depend on the difficulty of discrete logarithms or factoring, but on a second-preimage-resistant cryptographic hash function, the HSS/LMS signature algorithm is considered to be post-quantum secure. One use of post-quantum-secure signatures is the protection of software updates, perhaps using the format described in <xref target="RFC4108"derivedContent="FWPROT"/>,/>, to enable deployment of software that implements new cryptosystems.</t> </section> <section> <name>Changes Since RFC 8708</name> <t> At the time RFC 8708 was published, there were no plans to put an HSS/LMS public key in a certificate. The expectation was that the HSS/LMS public key would be distributed by some other means. Today, there are plans to put an HSS/LMS public key in a certificate <xref target="I-D.ietf-lamps-x509-shbs"/>. The KEY field of the pk-HSS-LMS-HashSig definition in the ASN.1 module does not come into play when using HSS/LMS signatures in the CMS; however, it needs to be consistent with the conventions for carrying an HSS/LMS public key in a certificate. The pk-HSS-LMS-HashSig definition is updated to reflect no ASN.1 wrapping for the public key. These changes resolve <xref target="Err7960"/> and <xref target="Err7963"/>.</t> <t> Additional HSS/LMS tree sizes have been defined. The list in <xref target="sect-2.2"/> was expanded to include the recently defined ones.</t> <t> Additional LM-OTS Signatures have been defined. The list in <xref target="sect-2.3"/> was expanded to include the recently defined ones.</t> <t>Provide moreMore detail has been provided in <xref target="sect-4"/> regarding allowed values in the X.509 certificate key usage extension for an HSS/LMS public key.</t> </section> </section> <section anchor="sect-2"> <name>HSS/LMS Hash-Based Signature Algorithm Overview</name> <t> Merkle Tree Signatures (MTS) are a method for signing a large but fixed number of messages. An MTS system depends on a one-time signature method and a collision-resistant hash function.</t> <t> This specification makes use of the hash-based algorithm specified in <xref target="RFC8554"derivedContent="HASHSIG"/>,/>, which is the Leighton and Micali adaptation <xref target="LM"derivedContent="LM"/>/> of the original Lamport-Diffie-Winternitz-Merkle one-time signature system <xref target="M1979"derivedContent="M1979"/>/> <xref target="M1987"derivedContent="M1987"/>/> <xref target="M1989a"derivedContent="M1989a"/>/> <xref target="M1989b"derivedContent="M1989b"/>.</t>/>.</t> <t> As implied by the name, the hash-based signature algorithm depends on a collision-resistant hash function. The hash-based signature algorithm specified in <xref target="RFC8554"derivedContent="HASHSIG"/>/> uses only the SHA-256 one-way hash function <xref target="SHS"derivedContent="SHS"/>,/>, but it establishes an IANA registry <xref target="IANA-LMS"/> to permit the registration of additional one-way hash functions in the future.</t> <section anchor="sect-2.1"> <name>Hierarchical Signature System (HSS)</name> <t> The MTS system specified in <xref target="RFC8554"derivedContent="HASHSIG"/>/> uses a hierarchy of trees. The N-time Hierarchical Signature System (HSS) allows subordinate trees to be generated when needed by the signer. Otherwise, generation of the entire tree might take weeks or longer.</t> <t> An HSS signature as specified in <xref target="RFC8554"derivedContent="HASHSIG"/>/> carries the number of signed public keys (Nspk), followed by that number of signed public keys, followed by the LMS signature as described in <xref target="sect-2.2"/>. The public key for the topmost LMS tree is the public key of the HSS system. The LMS private key in the parent tree signs the LMS public key in the child tree, and the LMS private key in the bottom-most tree signs the actual message. The signature over the public key and the signature over the actual message are LMS signatures as described in <xref target="sect-2.2"/>.</t> <t> The elements of the HSS signature value for a standalone tree (a top tree with no children) can be summarized as:</t> <artwork align="left"> u32str(0) || lms_signature /* signature of message */ </artwork> <t>where, u32str() and || are used as defined in <xref target="RFC8554"derivedContent="HASHSIG"/>.</t>/>.</t> <t> The elements of the HSS signature value for a tree with Nspk signed public keys can be summarized as:</t> <artwork align="left"> u32str(Nspk) || signed_public_key[0] || signed_public_key[1] || ... signed_public_key[Nspk-2] || signed_public_key[Nspk-1] || lms_signature /* signature of message */ </artwork> <t> where, as defined in <xref target="RFC8554" sectionFormat="of" section="3.3"derivedContent="HASHSIG"/>,/>, the signed_public_key structure contains the lms_signature over the public key, followed by the public key itself. Note that Nspk is the number of levels in the hierarchy of trees minus 1.</t> </section> <section anchor="sect-2.2"> <name>Leighton-Micali Signature (LMS)</name> <t> Each tree in the system specified in <xref target="RFC8554"derivedContent="HASHSIG"/>/> uses the Leighton-Micali Signature (LMS) system. LMS systems have two parameters. The first parameter is the height of the tree, h, which is the number of levels in the tree minus one. The <xref target="RFC8554"derivedContent="HASHSIG"/>/> specification supports five values for this parameter: h=5, h=10, h=15, h=20, and h=25. There are2^h2<sup>h</sup> leaves in the tree. The second parameter, m, is the number of bytes output by the hash function, and it is the amount of data associated with each node in the tree. The <xref target="RFC8554"derivedContent="HASHSIG"/>/> specification supports the SHA-256 hash function <xref target="SHS"derivedContent="SHS"/>,/>, with m=32.Additional,Additional LMS Signature parameter sets have been registered at <xref target="IANA-LMS"/>.</t> <t> As specified in <xref target="RFC8554"derivedContent="HASHSIG"/>,/>, the LMS public key consists of four elements: the lms_algorithm_type from the list above, the otstype to identify the Leighton-Micali One-Time Signature (LM-OTS) type as discussed in <xref target="sect-2.3"/>, the private key identifier (I) as described in <xref target="RFC8554" sectionFormat="of" section="5.3"derivedContent="HASHSIG"/>,/>, and the m-byte string associated with the root node of the tree (T[1]).</t> <t> The LMS public key can be summarized as:</t> <artwork align="left"> u32str(lms_algorithm_type) || u32str(otstype) || I || T[1] </artwork> <t> As specified in <xref target="RFC8554"derivedContent="HASHSIG"/>,/>, an LMS signature consists of four elements: the number of the leaf (q) associated with the LM-OTS signature value, an LM-OTS signature value as described in <xref target="sect-2.3"/>, a typecode indicating the particular LMS algorithm, and an array of values that is associated with the path through the tree from the leaf associated with the LM-OTS signature value to the root. The array of values contains the siblings of the nodes on the path from the leaf to the root but does not contain the nodes on the path itself. The array for a tree with height h will have h values. The first value is the sibling of the leaf, the next value is the sibling of the parent of the leaf, and so on up the path to the root.</t> <t> The four elements of the LMS signature value can be summarized as:</t> <artwork align="left"> u32str(q) || ots_signature || u32str(type) || path[0] || path[1] || ... || path[h-1] </artwork> </section> <section anchor="sect-2.3"> <name>Leighton-Micali One-Time Signature (LM-OTS) Algorithm</name> <t> Merkle Tree Signatures (MTS) depend on a one-time signature method, and <xref target="RFC8554"derivedContent="HASHSIG"/>/> specifies the use of the LM-OTS, which has five parameters:</t> <dlindent="5">indent="5" newline="false" spacing="normal"> <dt>n:</dt> <dd>The length in bytes of the hash function output.</dd> <dt>H:</dt> <dd>A preimage-resistant hash function that accepts byte strings of any length and returns an n-byte string.</dd> <dt>w:</dt> <dd>The width in bits of the Winternitz coefficients. <xref target="RFC8554"derivedContent="HASHSIG"/>/> supports four values for this parameter: w=1, w=2, w=4, and w=8.</dd> <dt>p:</dt> <dd>The number of n-byte string elements that make up the LM-OTS signature value.</dd> <dt>ls:</dt> <dd>The number of bits that are left-shifted in the final step of the checksum function, which is defined in <xref target="RFC8554" sectionFormat="of" section="4.4"derivedContent="HASHSIG"/>.</dd>/>.</dd> </dl> <t> The values of p and ls are dependent on the choices of the parameters n and w, as described in <xref target="RFC8554" sectionFormat="of"section="B" derivedContent="HASHSIG"/>.</t>section="B"/>.</t> <!-- [rfced] For clarity, should the four variants be listed in this sentence? (We note they were listed in RFC 8708.) RFC 8554 [HASHSIG] contains one instance of 'variant' but not regarding this concept. Also, perhaps drop the "The" because within this document it's referred to as "the [HASHSIG] specification" or simply "[HASHSIG]". Original: The [HASHSIG] specifies four LM-OTS variants. Perhaps (A): [or, it could be a bulleted list as in RFC 8708] [HASHSIG] specifies four LM-OTS variants (LMOTS_SHA256_N32_W1, LMOTS_SHA256_N32_W2, LMOTS_SHA256_N32_W4, and LMOTS_SHA256_N32_W8). Or (B): [referring to Table 1] [HASHSIG] specifies four LM-OTS variants (as listed in Table 1 of [HASHIG]). --> <t> The <xref target="RFC8554"derivedContent="HASHSIG"/>/> specifies four LM-OTS variants.Additional,Additional LM-OTS Signature parameter sets have been registered at <xref target="IANA-LMS"/>.</t> <t> Signing involves the generation of C, an n-byte random value.</t> <t> The LM-OTS signature value can be summarized as the identifier of the LM-OTS variant, the random value, and a sequence of hash values (y[0] through y[p-1]) that correspond to the elements of the public key, as described in <xref target="RFC8554" sectionFormat="of" section="4.5"derivedContent="HASHSIG"/>:</t>/>:</t> <artwork align="left"> u32str(otstype) || C || y[0] || ... || y[p-1] </artwork> </section> </section> <section> <name>Algorithm Identifiers and Parameters</name> <t> The algorithm identifier for an HSS/LMS hash-based signature is: </t> <sourcecode type="asn.1" markers="false"> 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 } </sourcecode> <t> When this object identifier is used for an HSS/LMS signature, the AlgorithmIdentifier parameters field <bcp14>MUST</bcp14> be absent (that is, the parameters are not present, and the parameters are not set to NULL).</t> <t> In the CMS, the HSS/LMS signature value is a large OCTET STRING. The HSS/LMS signature generation is described in <xref target="sect-2"/> of this document. The signature format is designed for easy parsing. The HSS, LMS, and LM-OTS components of the signature value each include a counter and a typecode that indirectly provide all of the information that is needed to parse the value during signature validation.</t> <t> The signature value identifies the hash function used in the HSS/LMS tree.</t> </section> <section anchor="sect-4"> <name>HSS/LMS Public Key Identifier</name> <t> The AlgorithmIdentifier for an HSS/LMS public key uses the id-alg-hss-lms-hashsig object identifier, and the parameters field <bcp14>MUST</bcp14> be absent.</t> <t> When this AlgorithmIdentifier appears in the SubjectPublicKeyInfo field of a certification authority (CA) X.509 certificate <xref target="RFC5280"derivedContent="RFC5280"/>,/>, the certificate key usage extension <bcp14>MUST</bcp14> contain at least one of the following values: digitalSignature, nonRepudiation, keyCertSign, and cRLSign. However, it <bcp14>MUST NOT</bcp14> contain other values.</t><t><!--[rfced] FYI, this sentence was updated per mail from the author on 25 September 2024. Original: When this AlgorithmIdentifier 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: digitalSignature or nonRepudiation. Current: When this AlgorithmIdentifier 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: digitalSignature, nonRepudiation, or cRLSign. --> <!--[rfced] Regarding this comment in the ASN.1 (two instances in this document), could it be rephrased for clarity? Yes, this comment is part of the referenced [Err7963]. (Below, two hyphens have been replaced by one in order to include this as a comment in the XML file.) Original: - KEY no ASN.1 wrapping - Perhaps (A): - KEY has no ASN.1 wrapping - Or (B): - No ASN.1 wrapping for KEY - --> <t> When this AlgorithmIdentifier appears in the SubjectPublicKeyInfo field of an end-entity X.509 certificate <xref target="RFC5280"derivedContent="RFC5280"/>,/>, the certificate key usage extension <bcp14>MUST</bcp14> contain at least one of the following:digitalSignaturedigitalSignature, nonRepudiation, ornonRepudiation.cRLSign. However, it <bcp14>MUST NOT</bcp14> contain other values.</t> <sourcecode type="asn.1" markers="false"> 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 } } HSS-LMS-HashSig-PublicKey ::= OCTET STRING </sourcecode> <t> 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 version of the document that became <xref target="RFC8554"derivedContent="HASHSIG"/>.</t>/>.</t> <t> When the public key appears outside a certificate, it is an OCTET STRING. Like the signature format, it is designed for easy parsing. The value is the number of levels in the public key, L, followed by the LMS public key.</t> <t> The HSS/LMS public key value can be described as:</t> <artwork align="left"> u32str(L) || lms_public_key </artwork> <t> The public key for the topmost LMS tree is the public key of the HSS system. When L=1, the HSS system is a single tree.</t> </section> <section anchor="sect-5"> <name>Signed-Data Conventions</name> <t> As specified in <xref target="RFC5652"derivedContent="CMS"/>,/>, the digital signature is produced from the message digest and the signer's private key. The signature is computed over different values depending on whether signed attributes are absent or present.</t> <t> When signed attributes are absent, the HSS/LMS signature is computed over the content. When signed attributes are present, a hash is computed over the content using the same hash function that is used in the HSS/LMS tree, then a message-digest attribute is constructed with the hash of the content, and then the HSS/LMS signature is computed over the DER-encoded set of signed attributes (which <bcp14>MUST</bcp14> include a content-type attribute and a message-digest attribute). In summary:</t> <sourcecode name="pseudocode" type="" markers="false"> IF (signed attributes are absent) THEN HSS_LMS_Sign(content) ELSE message-digest attribute = Hash(content); HSS_LMS_Sign(DER(SignedAttributes)) </sourcecode> <t> When using <xref target="RFC8554"derivedContent="HASHSIG"/>,/>, the fields in the SignerInfo are used as follows:</t><ul> <li> digestAlgorithm<ul spacing="normal"> <li><t>digestAlgorithm <bcp14>MUST</bcp14> contain the one-way hash function used in the HSS/LMS tree. For convenience, the AlgorithmIdentifier for SHA-256 from <xreftarget="RFC5912" derivedContent="PKIXASN1"/>target="RFC5912"/> and the AlgorithmIdentifier for SHAKE256 from <xreftarget="RFC8692" derivedContent="SHAKEASN1"/>target="RFC8692"/> are repeatedhere:</li> </ul>here:</t> <sourcecode type="asn.1" markers="false"> mda-sha256 DIGEST-ALGORITHM ::= { IDENTIFIER id-sha256 PARAMS TYPE NULL ARE preferredAbsent } id-sha256 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistAlgorithms(4) hashalgs(2) 1 } mda-shake256 DIGEST-ALGORITHM ::= { IDENTIFIER id-shake256 } id-shake256 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistAlgorithm(4) hashAlgs(2) 12 } </sourcecode><ul></li> <li> signatureAlgorithm <bcp14>MUST</bcp14> contain id-alg-hss-lms-hashsig, and the algorithm parameters field <bcp14>MUST</bcp14> be absent.</li> <li> signature contains the single HSS/LMS signature value resulting from the signing operation as specified in <xreftarget="RFC8554" derivedContent="HASHSIG"/>.</li>target="RFC8554"/>.</li> </ul> </section> <section anchor="sect-6"> <name>Security Considerations</name> <t> Implementations <bcp14>MUST</bcp14> protect the private keys. Compromise of the private keys will result in the ability to forge signatures. Along with the private key, the implementation <bcp14>MUST</bcp14> keep track of which leaf nodes in the tree have been used. Loss of integrity of this tracking data can cause a one-time key to be used more than once. As a result, when a private key and the tracking data are stored on non-volatile media or in a virtual machine environment, failed writes, virtual machine snapshotting or cloning, and other operational concerns must be considered to ensure confidentiality and integrity.</t> <t> When generating an LMS key pair, an implementation <bcp14>MUST</bcp14> generate each key pair independently of all other key pairs in the HSS tree.</t> <t> An implementation <bcp14>MUST</bcp14> ensure that an LM-OTS private key is used to generate a signature only one time and ensure that it cannot be used for any other purpose.</t> <t> The generation of private keys relies on random numbers. The use of inadequate pseudorandom number generators (PRNGs) to generate these values can result in little or no security. An attacker may find it much easier to reproduce the PRNG environment that produced the keys, searching the resulting small set of possibilities, rather than brute-force searching the whole key space. The generation of quality random numbers is difficult, and <xreftarget="RFC4086" derivedContent="RFC4086"/>target="RFC4086"/> offers important guidance in this area.</t> <t> The generation of hash-based signatures also depends on random numbers. While the consequences of an inadequate pseudorandom number generator (PRNG) to generate these values is much less severe than in the generation of private keys, the guidance in <xreftarget="RFC4086" derivedContent="RFC4086"/>target="RFC4086"/> remains important.</t> <t> When computing signatures, the same hash function <bcp14>SHOULD</bcp14> be used to compute the message digest of the content and the signed attributes, if they are present.</t> </section> <section anchor="sect-7"> <name>IANA Considerations</name> <t> In the "SMI Security for S/MIME Module Identifier (1.2.840.113549.1.9.16.0)" registry, IANAis requested to changehas changed the reference for value 64 topoint tothis document.</t> <t> In the "SMI Security for S/MIME Algorithms (1.2.840.113549.1.9.16.3)" registry, IANAis requested to changehas changed the reference for value 17 topoint tothis document.</t> </section> </middle> <back> <displayreference target="RFC8554" to="HASHSIG"/> <displayreference target="RFC5652" to="CMS"/> <displayreference target="RFC5911" to="CMSASN1"/> <displayreference target="RFC6268" to="CMSASN1U"/> <displayreference target="RFC4108" to="FWPROT"/> <displayreference target="RFC5912" to="PKIXASN1"/> <displayreference target="I-D.ietf-lamps-x509-shbs" to="X.509-S-HBS"/> <references> <name>References</name> <references> <name>Normative References</name> <!-- [rfced] [ASN1-B] references the 2015 version of ITU-T Recommendation X.680. This ITU-T Recommendation has been superseded a new version published in February 2021 (https://www.itu.int/rec/t-rec-x.680/en). Would you like to update this reference to use the most current version and add that URL to the reference? --> <reference anchor="ASN1-B"quoteTitle="true" derivedAnchor="ASN1-B">quoteTitle="true"> <front> <title>Information technology -- Abstract Syntax Notation One (ASN.1): Specification of basic notation</title> <seriesInfo name="ITU-T" value="Recommendation X.680"/> <author> <organization showOnFrontPage="true">ITU-T</organization> </author> <date month="August" year="2015"/> </front> </reference> <!-- [rfced] [ASN1-E] references the 2015 version of ITU-T Recommendation X.690. This ITU-T Recommendation has been superseded by the version in February 2021 (https://www.itu.int/rec/t-rec-x.690/en). Would you like to update this reference to use the most current version and add that URL to the reference? --> <reference anchor="ASN1-E"quoteTitle="true" derivedAnchor="ASN1-E">quoteTitle="true"> <front> <title>Information technology -- ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)</title> <seriesInfo name="ITU-T" value="Recommendation X.690"/> <author> <organization showOnFrontPage="true">ITU-T</organization> </author> <date month="August" year="2015"/> </front> </reference><reference anchor="RFC5652" target="https://www.rfc-editor.org/info/rfc5652" quoteTitle="true" derivedAnchor="CMS"> <front> <title>Cryptographic Message Syntax (CMS)</title> <author initials="R." surname="Housley" fullname="R. Housley"> <organization/> </author> <date year="2009" month="September"/> </front> <seriesInfo name="STD" value="70"/> <seriesInfo name="RFC" value="5652"/> <seriesInfo name="DOI" value="10.17487/RFC5652"/> </reference> <reference anchor="RFC8554" target="https://www.rfc-editor.org/info/rfc8554" quoteTitle="true" derivedAnchor="HASHSIG"> <front> <title>Leighton-Micali Hash-Based Signatures</title> <author initials="D." surname="McGrew" fullname="D. McGrew"> <organization/> </author> <author initials="M." surname="Curcio" fullname="M. Curcio"> <organization/> </author> <author initials="S." surname="Fluhrer" fullname="S. Fluhrer"> <organization/> </author> <date year="2019" month="April"/> </front> <seriesInfo name="RFC" value="8554"/> <seriesInfo name="DOI" value="10.17487/RFC8554"/> </reference> <reference anchor="RFC2119" target="https://www.rfc-editor.org/info/rfc2119" quoteTitle="true" derivedAnchor="RFC2119"> <front> <title>Key words for use in RFCs to Indicate Requirement Levels</title> <author initials="S." surname="Bradner" fullname="S. Bradner"> <organization/> </author> <date year="1997" month="March"/> </front> <seriesInfo name="BCP" value="14"/> <seriesInfo name="RFC" value="2119"/> <seriesInfo name="DOI" value="10.17487/RFC2119"/> </reference> <reference anchor="RFC5280" target="https://www.rfc-editor.org/info/rfc5280" quoteTitle="true" derivedAnchor="RFC5280"> <front> <title>Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile</title> <author initials="D." surname="Cooper" fullname="D. Cooper"> <organization/> </author> <author initials="S." surname="Santesson" fullname="S. Santesson"> <organization/> </author> <author initials="S." surname="Farrell" fullname="S. Farrell"> <organization/> </author> <author initials="S." surname="Boeyen" fullname="S. Boeyen"> <organization/> </author> <author initials="R." surname="Housley" fullname="R. Housley"> <organization/> </author> <author initials="W." surname="Polk" fullname="W. Polk"> <organization/> </author> <date year="2008" month="May"/> </front> <seriesInfo name="RFC" value="5280"/> <seriesInfo name="DOI" value="10.17487/RFC5280"/> </reference> <reference anchor="RFC8174" target="https://www.rfc-editor.org/info/rfc8174" quoteTitle="true" derivedAnchor="RFC8174"> <front> <title>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words</title> <author initials="B." surname="Leiba" fullname="B. Leiba"> <organization/> </author> <date year="2017" month="May"/> </front> <seriesInfo name="BCP" value="14"/> <seriesInfo name="RFC" value="8174"/> <seriesInfo name="DOI" value="10.17487/RFC8174"/> </reference><xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5652.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8554.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.2119.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5280.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8174.xml"/> <reference anchor="SHS" quoteTitle="true"target="https://doi.org/10.6028/NIST.FIPS.180-4" derivedAnchor="SHS">target="https://doi.org/10.6028/NIST.FIPS.180-4"> <front> <title>Secure Hash Standard (SHS)</title> <seriesInfo name="FIPS PUB" value="180-4"/> <author> <organization showOnFrontPage="true">National Institute of Standards andTechnology (NIST)</organization>Technology</organization> </author> <date month="August" year="2015"/> </front> <seriesInfo name="DOI" value="10.6028/NIST.FIPS.180-4"/> </reference> <reference anchor="SHA3" quoteTitle="true"target="https://doi.org/10.6028/NIST.FIPS.202" derivedAnchor="SHA3">target="https://doi.org/10.6028/NIST.FIPS.202"> <front> <title>SHA-3 Standard: Permutation-Based Hash and Extendable-Output Functions</title> <seriesInfo name="DOI" value="10.6028/NIST.FIPS.202"/> <seriesInfo name="FIPS PUB" value="202"/> <author> <organization showOnFrontPage="true">National Institute of Standards and Technology</organization> </author> <date year="2015" month="August"/> </front> </reference><reference anchor="RFC8692" target="https://www.rfc-editor.org/info/rfc8692"> <front> <title>Internet X.509 Public Key Infrastructure: Additional Algorithm Identifiers for RSASSA-PSS and ECDSA Using SHAKEs</title> <author fullname="P. Kampanakis" initials="P." surname="Kampanakis"/> <author fullname="Q. Dang" initials="Q." surname="Dang"/> <date month="December" year="2019"/> </front> <seriesInfo name="RFC" value="8692"/> <seriesInfo name="DOI" value="10.17487/RFC8692"/> </reference><xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8692.xml"/> </references> <references> <name>Informative References</name> <reference anchor="Err7960" target="https://www.rfc-editor.org/errata/eid7960" quoteTitle="false"> <front> <title>RFCErrata ReportErrata, Erratum ID 7960</title> <author> <organization/> </author><date year="2024" month="May" day="28"/></front> <seriesInfo name="RFC" value="8708"/> </reference> <reference anchor="Err7963" target="https://www.rfc-editor.org/errata/eid7963" quoteTitle="false"> <front> <title>RFCErrata ReportErrata, Erratum ID 7963</title> <author> <organization/> </author><date year="2024" month="May" day="29"/></front> <seriesInfo name="RFC" value="8708"/> </reference><reference anchor="I-D.ietf-lamps-x509-shbs" target="https://datatracker.ietf.org/doc/draft-ietf-lamps-x509-shbs-04"> <front> <title>Internet X.509 Public Key Infrastructure: Algorithm Identifiers for HSS and XMSS</title> <author fullname="Daniel Van Geest" initials="D." surname="Van Geest"> <organization>CryptoNext Security</organization> </author> <author fullname="Kaveh Bashiri" initials="K." surname="Bashiri"> <organization>BSI</organization> </author> <author fullname="Scott Fluhrer" initials="S." surname="Fluhrer"> <organization>Cisco Systems</organization> </author> <author fullname="Stefan-Lukas Gazdag" initials="S." surname="Gazdag"> <organization>genua GmbH</organization> </author> <author fullname="Stavros Kousidis" initials="S." surname="Kousidis"> <organization>BSI</organization> </author> <date day="25" month="July" year="2024"/> </front> <seriesInfo name="Internet-Draft" value="draft-ietf-lamps-x509-shbs-04"/> </reference><xi:include href="https://bib.ietf.org/public/rfc/bibxml3/reference.I-D.ietf-lamps-x509-shbs.xml"/> <reference anchor="BH2013" target="https://media.blackhat.com/us-13/us-13-Stamos-The-Factoring-Dead.pdf"quoteTitle="true" derivedAnchor="BH2013">quoteTitle="true"> <front> <title>The Factoring Dead: Preparing for the Cryptopocalypse</title> <author fullname="Thomas Ptacek" initials="T." surname="Ptacek"/> <author fullname="Tom Ritter" initials="T." surname="Ritter"/> <author fullname="Javed Samuel" initials="J." surname="Samuel"/> <author fullname="Alex Stamos" initials="A." surname="Stamos"/> <date month="August" year="2013"/> </front> </reference><reference anchor="RFC5911" target="https://www.rfc-editor.org/info/rfc5911" quoteTitle="true" derivedAnchor="CMSASN1"> <front> <title>New ASN.1 Modules for Cryptographic Message Syntax (CMS) and S/MIME</title> <author initials="P." surname="Hoffman" fullname="P. Hoffman"> <organization/> </author> <author initials="J." surname="Schaad" fullname="J. Schaad"> <organization/> </author> <date year="2010" month="June"/> </front> <seriesInfo name="RFC" value="5911"/> <seriesInfo name="DOI" value="10.17487/RFC5911"/> </reference> <reference anchor="RFC6268" target="https://www.rfc-editor.org/info/rfc6268" quoteTitle="true" derivedAnchor="CMSASN1U"> <front> <title>Additional New ASN.1 Modules for the Cryptographic Message Syntax (CMS) and the Public Key Infrastructure Using X.509 (PKIX)</title> <author initials="J." surname="Schaad" fullname="J. Schaad"> <organization/> </author> <author initials="S." surname="Turner" fullname="S. Turner"> <organization/> </author> <date year="2011" month="July"/> </front> <seriesInfo name="RFC" value="6268"/> <seriesInfo name="DOI" value="10.17487/RFC6268"/> </reference> <reference anchor="RFC4108" target="https://www.rfc-editor.org/info/rfc4108" quoteTitle="true" derivedAnchor="FWPROT"> <front> <title>Using Cryptographic Message Syntax (CMS) to Protect Firmware Packages</title> <author initials="R." surname="Housley" fullname="R. Housley"> <organization/> </author> <date year="2005" month="August"/> </front> <seriesInfo name="RFC" value="4108"/> <seriesInfo name="DOI" value="10.17487/RFC4108"/> </reference><xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5911.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.6268.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.4108.xml"/> <reference anchor="IANA-LMS" target="https://www.iana.org/assignments/leighton-micali-signatures/"quoteTitle="true" derivedAnchor="IANA-LMS">quoteTitle="true"> <front> <title>Leighton-Micali Signatures (LMS)</title> <author> <organization showOnFrontPage="true">IANA</organization> </author> <date/> </front> </reference> <!-- [rfced] For [LM], we found the following URL: https://patents.google.com/patent/US5432852A/ Would you like to add it to the reference? --> <reference anchor="LM"quoteTitle="true" derivedAnchor="LM">quoteTitle="true"> <front> <title>Large provably fast and secure digital signature schemes based on secure hash functions</title><seriesInfo name="U.S." value="Patent 5,432,852"/><author fullname="T. Leighton" initials="T." surname="Leighton"/> <author fullname="S. Micali" initials="S." surname="Micali"/> <date month="July" year="1995"/> </front> <refcontent>U.S. Patent 5,432,852</refcontent> </reference> <reference anchor="M1979"quoteTitle="true" derivedAnchor="M1979">quoteTitle="true"> <front> <title>Secrecy, Authentication, and Public Key Systems</title><seriesInfo name="Technical Report" value="No. 1979-1"/> <seriesInfo name="Information Systems Laboratory," value="Stanford University"/><author fullname="R. Merkle" initials="R." surname="Merkle"/> <date year="1979"/> </front> <seriesInfo name="Technical Report" value="No. 1979-1"/> <refcontent>Information Systems Laboratory, Stanford University</refcontent> </reference> <reference anchor="M1987" quoteTitle="true"target="https://doi.org/10.1007/3-540-48184-2_32" derivedAnchor="M1987">target="https://doi.org/10.1007/3-540-48184-2_32"> <front> <title>A Digital Signature Based on a Conventional Encryption Function</title><seriesInfo name="DOI" value="10.1007/3-540-48184-2_32"/><author fullname="R. Merkle" initials="R." surname="Merkle"/> <date year="1988"/> </front> <refcontent>Advances in Cryptology -- CRYPTO '87 Proceedings</refcontent> <refcontent>Lecture Notes in ComputerScienceScience, Vol. 293</refcontent> <seriesInfo name="DOI" value="10.1007/3-540-48184-2_32"/> </reference> <reference anchor="M1989a" quoteTitle="true"target="https://doi.org/10.1007/0-387-34805-0_21" derivedAnchor="M1989a">target="https://doi.org/10.1007/0-387-34805-0_21"> <front> <title>A Certified Digital Signature</title><seriesInfo name="DOI" value="10.1007/0-387-34805-0_21"/><author fullname="R. Merkle" initials="R." surname="Merkle"/> <date year="1990"/> </front> <refcontent>Advances in Cryptology -- CRYPTO '89 Proceedings</refcontent> <refcontent>Lecture Notes in ComputerScienceScience, Vol. 435</refcontent> <seriesInfo name="DOI" value="10.1007/0-387-34805-0_21"/> </reference> <reference anchor="M1989b" quoteTitle="true"target="https://doi.org/10.1007/0-387-34805-0_40" derivedAnchor="M1989b">target="https://doi.org/10.1007/0-387-34805-0_40"> <front> <title>One Way Hash Functions and DES</title> <seriesInfo name="DOI" value="10.1007/0-387-34805-0_40"/> <author fullname="R. Merkle" initials="R." surname="Merkle"/> <date year="1990"/> </front> <refcontent>Advances in Cryptology -- CRYPTO '89 Proceedings</refcontent> <refcontent>Lecture Notes in ComputerScienceScience, Vol. 435</refcontent> </reference> <reference anchor="NAS2019" quoteTitle="true"target="https://doi.org/10.17226/25196" derivedAnchor="NAS2019">target="https://doi.org/10.17226/25196"> <front> <title>Quantum Computing: Progress and Prospects</title> <seriesInfo name="DOI" value="10.17226/25196"/> <author> <organization showOnFrontPage="true">National Academies of Sciences, Engineering, and Medicine</organization> </author> <date year="2019"/> </front> <refcontent>The National Academies Press</refcontent> </reference><reference anchor="RFC5912" target="https://www.rfc-editor.org/info/rfc5912" quoteTitle="true" derivedAnchor="PKIXASN1"> <front> <title>New ASN.1 Modules for the Public Key Infrastructure Using X.509 (PKIX)</title> <author initials="P." surname="Hoffman" fullname="P. Hoffman"> <organization/> </author> <author initials="J." surname="Schaad" fullname="J. Schaad"> <organization/> </author> <date year="2010" month="June"/> </front> <seriesInfo name="RFC" value="5912"/> <seriesInfo name="DOI" value="10.17487/RFC5912"/> </reference><xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5912.xml"/> <reference anchor="PQC" target="https://doi.org/10.1007/978-3-540-88702-7_1"quoteTitle="true" derivedAnchor="PQC">quoteTitle="true"> <front> <title>Introduction to post-quantum cryptography</title><seriesInfo name="DOI" value="10.1007/978-3-540-88702-7_1"/><author fullname="D. Bernstein" initials="D." surname="Bernstein"/> <date year="2009"/> </front></reference> <reference anchor="RFC4086" target="https://www.rfc-editor.org/info/rfc4086" quoteTitle="true" derivedAnchor="RFC4086"> <front> <title>Randomness Requirements for Security</title> <author initials="D." surname="Eastlake 3rd" fullname="D. Eastlake 3rd"> <organization/> </author> <author initials="J." surname="Schiller" fullname="J. Schiller"> <organization/> </author> <author initials="S." surname="Crocker" fullname="S. Crocker"> <organization/> </author> <date year="2005" month="June"/> </front> <seriesInfo name="BCP" value="106"/> <seriesInfo name="RFC" value="4086"/><refcontent>Post-Quantum Cryptography, Springer, pp. 1-14</refcontent> <seriesInfo name="DOI"value="10.17487/RFC4086"/>value="10.1007/978-3-540-88702-7_1"/> </reference> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.4086.xml"/> </references> </references> <section anchor="sect-appendix"> <name>ASN.1 Module</name> <t> The ASN.1 module in this appendix builds upon the modules in <xref target="RFC5911"/> and <xref target="RFC6268"/>.</t> <sourcecode type="asn.1" markers="true"> 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) } DEFINITIONS IMPLICIT TAGS ::= BEGIN EXPORTS ALL; IMPORTS PUBLIC-KEY, SIGNATURE-ALGORITHM, SMIME-CAPS FROM AlgorithmInformation-2009 -- RFC 5911 [CMSASN1] { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-algorithmInformation-02(58) } ; -- -- Object Identifiers -- 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 } id-alg-mts-hashsig OBJECT IDENTIFIER ::= id-alg-hss-lms-hashsig -- -- Signature Algorithm and Public Key -- sa-HSS-LMS-HashSig SIGNATURE-ALGORITHM ::= { IDENTIFIER id-alg-hss-lms-hashsig PARAMS ARE absent PUBLIC-KEYS { pk-HSS-LMS-HashSig } SMIME-CAPS { IDENTIFIED BY id-alg-hss-lms-hashsig } } 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 } } HSS-LMS-HashSig-PublicKey ::= OCTET STRING -- -- Expand the signature algorithm set used by CMS [CMSASN1U] -- SignatureAlgorithmSet SIGNATURE-ALGORITHM ::= { sa-HSS-LMS-HashSig, ... } -- -- Expand the S/MIME capabilities set used by CMS [CMSASN1] -- SMimeCaps SMIME-CAPS ::= { sa-HSS-LMS-HashSig.&smimeCaps, ... } END </sourcecode> </section> <section numbered="false" anchor="acknowledgements"> <name>Acknowledgements</name> <t> Many thanks to the people that provided comments on the draft documents that resulted in RFC 8708. Thanks to <contact fullname="Joe Clarke"/>, <contact fullname="Roman Danyliw"/>, <contact fullname="Scott Fluhrer"/>, <contact fullname="Jonathan Hammell"/>, <contact fullname="Ben Kaduk"/>, <contact fullname="Panos Kampanakis"/>, <contact fullname="Barry Leiba"/>, <contact fullname="John Mattsson"/>, <contact fullname="Jim Schaad"/>, <contact fullname="Sean Turner"/>, <contact fullname="Daniel Van Geest"/>, and <contact fullname="Dale Worley"/> for their careful review and comments.</t> <t> Many thanks to <contact fullname="Daniel Van Geest"/> for motivating the creation of this document.</t> </section> </back> <!--[rfced] May usage of "MTS" be updated as follows? Original: a variant of Merkle Tree Signatures (MTS) Perhaps: a variant of the Merkle Tree Signature (MTS) scheme. Original: Merkle Tree Signatures (MTS) are a method Perhaps: The Merkle Tree Signature (MTS) scheme is a method We find zero usage of "Merkle Tree Signatures (MTS)" (with plural 'Signatures') outside of RFC 8708, and the Wikipedia entry for "Merkle signature scheme" does not use "MTS". [For background, we did ask about this usage during AUTH48 for 8708; the current question is slightly different.] --> <!-- [rfced] Please review each artwork element and let us know if any should be marked as sourcecode (or another element) instead. In addition, please consider whether the "type" attribute of any sourcecode element should be set and/or has been set correctly. The current list of preferred values for "type" is available at <https://www.rfc-editor.org/rpc/wiki/doku.php?id=sourcecode-types>. If the current list does not contain an applicable type, feel free to suggest additions for consideration. Note that it is also acceptable to leave the "type" attribute not set. --> <!-- [rfced] Please review the "Inclusive Language" portion of the online Style Guide <https://www.rfc-editor.org/styleguide/part2/#inclusive_language> and let us know if any changes are needed. Updates of this nature typically result in more precise language, which is helpful for readers. Note that our script did not flag any words in particular, but this should still be reviewed as a best practice. --> </rfc>