LAMPS Working Group M. Richardson, Ed. Internet-Draft Sandelman Software Works Updates: 7030 (if approved) O. Friel Intended status: Standards Track Cisco Expires: 7 March 2025 D. von Oheimb Siemens D. Harkins The Industrial Lounge 3 September 2024 Clarification and enhancement of RFC7030 CSR Attributes definition draft-ietf-lamps-rfc7030-csrattrs-11 Abstract The Enrollment over Secure Transport (EST, RFC7030) is ambiguous in its specification of the CSR Attributes Response. This has resulted in implementation challenges and implementor confusion. This document updates RFC7030 (EST) and clarifies how the CSR Attributes Response can be used by an EST server to specify both CSR attribute OIDs and also CSR attribute values, in particular X.509 extension values, that the server expects the client to include in subsequent CSR request. Moreover, it provides new convenient and straightforward approach: using a template for CSR contents that may be partially filled in by the server. This also allows specifying a subject Distinguished Name (DN). Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. 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 7 March 2025. Richardson, et al. Expires 7 March 2025 [Page 1] Internet-Draft CSRAttrs September 2024 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. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. CSR Attributes Handling . . . . . . . . . . . . . . . . . . . 4 3.1. Extensions to RFC 7030 section 2.6. . . . . . . . . . . . 4 3.2. Extensions to RFC 7030 section 4.5.2. . . . . . . . . . . 4 3.3. Use of CSR templates . . . . . . . . . . . . . . . . . . 5 4. Co-existence with existing implementations . . . . . . . . . 10 5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 10 5.1. RFC8994/ACP subjectAltName with specific otherName . . . 10 5.1.1. Base64 encoded example . . . . . . . . . . . . . . . 10 5.1.2. ASN.1 DUMP output . . . . . . . . . . . . . . . . . . 10 5.2. RFC7030 original example . . . . . . . . . . . . . . . . 11 5.2.1. Base64 encoded example . . . . . . . . . . . . . . . 11 5.2.2. ASN.1 DUMP output . . . . . . . . . . . . . . . . . . 12 5.3. EST server requires a specific subjectAltName extension . . . . . . . . . . . . . . . . . . . . . . . . 13 5.3.1. Base64 encoded example . . . . . . . . . . . . . . . 13 5.3.2. ASN.1 DUMP output . . . . . . . . . . . . . . . . . . 13 5.4. Require a public key of a specific size . . . . . . . . . 15 5.4.1. Base64 encoded example . . . . . . . . . . . . . . . 15 5.4.2. ASN.1 DUMP output . . . . . . . . . . . . . . . . . . 15 5.5. Require a public key of a specific curve . . . . . . . . 15 5.5.1. Base64 encoded example . . . . . . . . . . . . . . . 15 5.5.2. ASN.1 DUMP output . . . . . . . . . . . . . . . . . . 16 5.6. Require a specific extension . . . . . . . . . . . . . . 16 5.6.1. Base64 encoded example . . . . . . . . . . . . . . . 16 5.6.2. ASN.1 DUMP output . . . . . . . . . . . . . . . . . . 17 6. Security Considerations . . . . . . . . . . . . . . . . . . . 18 6.1. Identity and Privacy Considerations . . . . . . . . . . . 18 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 18 9. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Richardson, et al. Expires 7 March 2025 [Page 2] Internet-Draft CSRAttrs September 2024 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 10.1. Normative References . . . . . . . . . . . . . . . . . . 18 10.2. Informative References . . . . . . . . . . . . . . . . . 20 Appendix A. ASN.1 Module . . . . . . . . . . . . . . . . . . . . 20 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21 1. Introduction Enrollment over Secure Transport [RFC7030] (EST) has been used in a wide variety of applications. In particular, [RFC8994] and [RFC8995] describe a way to use it in order to build out an autonomic control plane (ACP) [RFC8368]. The ACP requires that each node be given a very specific subjectAltName. In the ACP specification, the solution was for the EST server to use section 2.6 of [RFC7030] to convey to the EST client the actual subjectAltName that will end up in its certificate. As a result of some implementation challenges, it came to light that this particular way of using the CSR attributes was not universally agreed upon, and it was suggested that it went contrary to section 2.6. Section 2.6 says that the CSR attributes "can provide additional descriptive information that the EST server cannot access itself". This is extended to describe how the EST server can provide values that it demands to use. After significant discussion, it has been determined that Section 4.5 of [RFC7030] specification is sufficiently difficult to read and ambiguous to interpret that clarification is needed. This document motivates the different use cases, and provides additional worked out examples. Also, section 4.5.2 is extended to clarify the use of the existing ASN.1 syntax [X.680][X.690]. This covers all uses and is fully backward compatible with existing use. 2. Terminology 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. Richardson, et al. Expires 7 March 2025 [Page 3] Internet-Draft CSRAttrs September 2024 3. CSR Attributes Handling 3.1. Extensions to RFC 7030 section 2.6. Replace the second paragraph with the following text: These attributes can provide additional descriptive information that the EST server cannot access itself, such as the Media Access Control (MAC) address of an interface of the EST client. The EST server can also provide concrete values that it tells the client to include in the CSR, such as a specific X.509 Subject Alternative Name extension. Moreover, these attributes can indicate the type of the included public key or which crypto algorithms to use for the self-signature, such as a specific elliptic curve or a specific hash function that the client is expected to use when generating the CSR. 3.2. Extensions to RFC 7030 section 4.5.2. The ASN.1 syntax for CSR Attributes as defined in EST section 4.5.2 is as follows: CsrAttrs ::= SEQUENCE SIZE (0..MAX) OF AttrOrOID AttrOrOID ::= CHOICE (oid OBJECT IDENTIFIER, attribute Attribute } Attribute { ATTRIBUTE:IOSet } ::= SEQUENCE { type ATTRIBUTE.&id({IOSet}), values SET SIZE(1..MAX) OF ATTRIBUTE.&Type({IOSet}{@type}) } This remains unchanged, such that bits-on-the-wire compatibility is maintained. Key parts that were unclear were which OID to use in the 'type' field and that the 'values' field can contain an entire sequence of X.509 extensions. The OID to use for such attributes in the 'type' field MUST be extensionRequest, which has the numerical value 1.2.840.113549.1.9.14. There MUST be only one such Attribute. The 'values' field of this attribute MUST contain a set with exactly one element, and this element MUST be of type Extensions, as per Section 4.1 of [RFC5280]: Richardson, et al. Expires 7 March 2025 [Page 4] Internet-Draft CSRAttrs September 2024 Extensions ::= SEQUENCE SIZE (1..MAX) OF Extension Extension ::= SEQUENCE { extnID OBJECT IDENTIFIER, critical BOOLEAN DEFAULT FALSE, extnValue OCTET STRING -- contains the DER encoding of an ASN.1 value -- corresponding to the extension type identified -- by extnID } An Extension comprises the OID of the specific X.509 extension (extnID), optionally the 'critical' bit, and the extension value (extnValue). An Extensions structure, which is a sequence of elements of type Extension, MUST NOT include more than one element with a particiular extnID. With this understanding, the needs of [RFC8994] and [RFC8995] are satisfied with no change to the bits on the wire. 3.3. Use of CSR templates [RFC8295], Appendix B describes a mechanism that avoids the piecemeal inclusion of attributes that [RFC7030] documented. Instead, an entire CSR object is returned with various fields filled out, and other fields waiting to be filled in, in a pKCS7PDU attribute. In that approach, the pKCS7PDU attribute includes a Full PKI Data content type [RFC5272] and that in turn includes a CSR or CRMF formatted request; see [RFC6268] Sections 5 and 9, respectively. The drawback to that approach, particularly for the CSR, is that some useless fields have to be included; specifically, the signature field on the CSR is faked with an empty bit string. We avoid this drawback as follows. This specification defines the Certificate Request Information Template attribute for CsrAttrs, see Section 3.2, that is essentially a partially filled in PKCS#10 CSR minus the signature wrapper as follows: aa-certificationRequestInfoTemplate ATTRIBUTE ::= { TYPE CertificationRequestInfoTemplate IDENTIFIED BY id-aa-certificationRequestInfoTemplate } id-aa-certificationRequestInfoTemplate OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) Richardson, et al. Expires 7 March 2025 [Page 5] Internet-Draft CSRAttrs September 2024 smime(16) aa(2) csrinfo(TBD2) } CertificationRequestInfoTemplate ::= SEQUENCE { version INTEGER { v1(0) } (v1, ... ), subject NameTemplate OPTIONAL, subjectPKInfo SubjectPublicKeyInfoTemplate {{ PKInfoAlgorithms }} OPTIONAL, attributes [0] Attributes{{ CRIAttributes }} } NameTemplate ::= CHOICE { -- only one possibility for now -- rdnSequence RDNSequenceTemplate } RDNSequenceTemplate ::= SEQUENCE OF RelativeDistinguishedNameTemplate RelativeDistinguishedNameTemplate ::= SET SIZE (1 .. MAX) OF AttributeTypeAndValueTemplate { {SupportedAttributes} } AttributeTypeAndValueTemplate {ATTRIBUTE:AttrSet} ::= SEQUENCE { type ATTRIBUTE.&id({AttrSet}), value ATTRIBUTE.&Type({AttrSet}{@type}) OPTIONAL } SubjectPublicKeyInfoTemplate {PUBLIC-KEY: IOSet} ::= SEQUENCE { algorithm AlgorithmIdentifier {PUBLIC-KEY, {IOSet}}, subjectPublicKey BIT STRING OPTIONAL } pkcs-9-at-extensionRequestTemplate OBJECT IDENTIFIER ::= {pkcs-9 TBD3} extensionRequestTemplate ATTRIBUTE ::= { WITH SYNTAX ExtensionRequestTemplate SINGLE VALUE TRUE ID pkcs-9-at-extensionRequestTemplate } ExtensionRequestTemplate ::= ExtensionTemplates ExtensionTemplates ::= SEQUENCE SIZE (1..MAX) OF ExtensionTemplate ExtensionTemplate {EXTENSION:ExtensionSet} ::= SEQUENCE { extnID EXTENSION.&id({ExtensionSet}), critical BOOLEAN -- ( EXTENSION.&Critical({ExtensionSet}{@extnID})) DEFAULT FALSE, extnValue OCTET STRING (CONTAINING EXTENSION.&ExtnType({ExtensionSet}{@extnID})) OPTIONAL Richardson, et al. Expires 7 March 2025 [Page 6] Internet-Draft CSRAttrs September 2024 -- contains the DER encoding of the ASN.1 value -- corresponding to the extension type identified -- by extnID when present } Note that the CertificationRequestInfoTemplate closely resembles the CertificationRequestInfo from [RFC5912], Section 5: CertificationRequestInfo ::= SEQUENCE { version INTEGER { v1(0) } (v1,...), subject Name, subjectPKInfo SubjectPublicKeyInfo{{ PKInfoAlgorithms }}, attributes [0] Attributes{{ CRIAttributes }} } with the following differences. * The subject field is made OPTIONAL to cover the case the server does not provide any requrements on the subject name and its RDNs. * RelativeDistinguishedNames (RDNs) in the subject fields are allowed to be empty, which is achieved by adding OPTIONAL to the value field of AttributeTypeAndValueTemplate. This means that the client is required to provide an RDN of the given type and fill in its value. * The subjectPKInfo field is made OPTIONAL, such that the server can leave it out in case there are no requirements on the key.\ Otherwise the server specifies the algorithm of the key, i.e., the key type, in the algorithm field. The subjectPublicKey field contained in SubjectPublicKeyInfoTemplate is made OPTIONAL because usually it is left out, but in case the server needs to specify the size of an RSA key, the field is used to provide a dummy public key value of the desired RSA modulus length. * A new OID pkcs-9-at-extensionRequestTemplate and the related ExtensionTemplate structure is defind where the extnValue field is optional. If the field is absent this means that the client is required to provide an X.509 extension with the given extnID and potentially the critical flag and fill in its value. Richardson, et al. Expires 7 March 2025 [Page 7] Internet-Draft CSRAttrs September 2024 A similar method has been defined in CMP Updates [RFC9480] and the Lightweight CMP profile [RFC9483], Section 4.3.3, using a CSR template as defined for CRMF [RFC4211]. That method does not properly deal with empty RDNs (encoding them as empty strings), absent subjectPublicKey fields (encoding them as empty BIT STRING), and empty X.509v3 extension values (encoding them as empty OCTET STRING), which may cause issues with strict ASN.1 parsing and decoding. The version code MUST be v1 (0). If the subjectPKInfo field is present, it indicates the type of the key pair the client is expected to use, where the subjectPublicKey MUST NOT be given except if the algorithm indicates RSA. The attributes field MUST NOT contain multiple extensionRequestTemplate attributes and MUST NOT contain both extensionRequest and extensionRequestTemplate attributes. Suppose the server requires that the CSR will contain: * the subject field with a common name to be filled in by the EE and two organizational unit fields with given values "myDept" and "myGroup", * the publicKey field contains an Elliptic Curve Cryptography (ECC) key on curve secp256r1, * the subjectAltName X.509 extension with DNS name "www.myServer.com" and an IP address to be filled in, * the keyUsage extension marked critical with the value digitalSignature and keyAgreement, and * the extKeyUsage extension with values to be filled in by the EE. Then the CertificationRequestInfo structure constructed by the server will be as follows: SEQUENCE { INTEGER 0 SEQUENCE { SET { SEQUENCE { OBJECT IDENTIFIER commonName (2 5 4 3) } } SET { Richardson, et al. Expires 7 March 2025 [Page 8] Internet-Draft CSRAttrs September 2024 SEQUENCE { OBJECT IDENTIFIER organizationalUnitName (2 5 4 11) UTF8String "myDept" } } SET { SEQUENCE { OBJECT IDENTIFIER organizationalUnitName (2 5 4 11) UTF8String "myGroup" } } } SEQUENCE { SEQUENCE { OBJECT IDENTIFIER ecPublicKey (1 2 840 10045 2 1) OBJECT IDENTIFIER secp256r1 (1 2 840 10045 3 1 7) } } [0] { SEQUENCE { OBJECT IDENTIFIER extensionRequest (1 2 840 113549 1 9 TBD3) SET { SEQUENCE { SEQUENCE { OBJECT IDENTIFIER subjectAltName (2 5 29 17) OCTET STRING, encapsulates { SEQUENCE { [2] "www.myServer.com" [7] "" } } } SEQUENCE { OBJECT IDENTIFIER keyUsage (2 5 29 15) BOOLEAN TRUE OCTET STRING, encapsulates { BIT STRING 3 unused bits "10001"B } } SEQUENCE { OBJECT IDENTIFIER extKeyUsage (2 5 29 37) } } } } } } Richardson, et al. Expires 7 March 2025 [Page 9] Internet-Draft CSRAttrs September 2024 4. Co-existence with existing implementations Legacy servers MAY continue to use the [RFC7030] style piecemeal attribute/value pairs, and MAY also include the template style described in {#csrtemplate}. Clients which understand both MUST use the template only, and ignore all other CSRattrs elements. Older clients will ignore the new CertificateRequestInfoTemplate element. 5. Examples Each example has a high-level (English) explanation of what is expected. Some mapping back to the Attribute and Extension definitions above are included. The base64 DER encoding is then shown. The output of "dumpasn1" is then provided to detail what the contents are. 5.1. RFC8994/ACP subjectAltName with specific otherName A single subjectAltName extension is specified in a single Extension attribute. This is what might be created by an [RFC8995] Registrar that is asking for [RFC8994] AcpNodeName format otherNames. 5.1.1. Base64 encoded example The Base64: MGQwYgYJKoZIhvcNAQkOMVUwUwYDVR0RAQH/BEmgRzBFBggr BgEFBQcICgw5cmZjODk5NCtmZDczOWZjMjNjMzQ0MDExMjIz MzQ0NTUwMDAwMDAwMCtAYWNwLmV4YW1wbGUuY29t 5.1.2. ASN.1 DUMP output There is a single subjectAltName Extension with an Attribute with Extension type. Richardson, et al. Expires 7 March 2025 [Page 10] Internet-Draft CSRAttrs September 2024 <30 64> 0 100: SEQUENCE { <30 62> 2 98: SEQUENCE { <06 09> 4 9: OBJECT IDENTIFIER extensionRequest (1 2 840 113549 1 9 14) : (PKCS #9 via CRMF) <31 55> 15 85: SET { <30 53> 17 83: SEQUENCE { <06 03> 19 3: OBJECT IDENTIFIER subjectAltName (2 5 29 17) : (X.509 extension) <01 01> 24 1: BOOLEAN TRUE <04 49> 27 73: OCTET STRING : A0 47 30 45 06 08 2B 06 .G0E..+. : 01 05 05 07 08 0A 0C 39 .......9 : 72 66 63 38 39 39 34 2B rfc8994+ : 66 64 37 33 39 66 63 32 fd739fc2 : 33 63 33 34 34 30 31 31 3c344011 : 32 32 33 33 34 34 35 35 22334455 : 30 30 30 30 30 30 30 30 00000000 : 2B 40 61 63 70 2E 65 78 +@acp.ex : 61 6D 70 6C 65 2E 63 6F ample.co : 6D m : } : } : } : } 5.2. RFC7030 original example In this example, taken from [RFC7030], a few different attributes are included. 5.2.1. Base64 encoded example The Base64: MEEGCSqGSIb3DQEJBzASBgcqhkjOPQIBMQcGBSuBBAAiMBYG CSqGSIb3DQEJDjEJBgcrBgEBAQEWBggqhkjOPQQDAw== Richardson, et al. Expires 7 March 2025 [Page 11] Internet-Draft CSRAttrs September 2024 5.2.2. ASN.1 DUMP output 1. The challengePassword attribute is included to indicate that the CSR should include this value. 2. An ecPublicKey attribute is provided with the value secp384r1 to indicate what kind of key should be submitted. 3. An extensionRequest container with an OID 1.3.6.1.1.1.1.22 (macAddress), but without a value, to indicate that the CSR should include an X.509v3 extension with this value. 4. The ecdsaWithSHA384 OID is included to indicate what kind of hash is expected to be used for the self-signature of the PCKS#10 CSR structure. <30 41> 0 65: SEQUENCE { <06 09> 2 9: OBJECT IDENTIFIER challengePassword (1 2 840 113549 1 9 7) : (PKCS #9) <30 12> 13 18: SEQUENCE { <06 07> 15 7: OBJECT IDENTIFIER ecPublicKey (1 2 840 10045 2 1) : (ANSI X9.62 public key type) <31 07> 24 7: SET { <06 05> 26 5: OBJECT IDENTIFIER secp384r1 (1 3 132 0 34) : (SECG (Certicom) named elliptic curve) : } : } <30 16> 33 22: SEQUENCE { <06 09> 35 9: OBJECT IDENTIFIER extensionRequest (1 2 840 113549 1 9 14) : (PKCS #9 via CRMF) <31 09> 46 9: SET { <06 07> 48 7: OBJECT IDENTIFIER '1 3 6 1 1 1 1 22' : } : } <06 08> 57 8: OBJECT IDENTIFIER ecdsaWithSHA384 (1 2 840 10045 4 3 3) : (ANSI X9.62 ECDSA algorithm with SHA384) : } Richardson, et al. Expires 7 March 2025 [Page 12] Internet-Draft CSRAttrs September 2024 5.3. EST server requires a specific subjectAltName extension This example is the same as the previous one except that instead of the OID for a macAddress, a subjectAltName is specified as the only Extension element. 5.3.1. Base64 encoded example The Base64: MGYGCSqGSIb3DQEJBzASBgcqhkjOPQIBMQcGBSuBBAAiMDsG CSqGSIb3DQEJDjEuMCwGA1UdEQEB/wQioCAwHgYIKwYBBQUH CAoMEnBvdGF0b0BleGFtcGxlLmNvbQYIKoZIzj0EAwM= 5.3.2. ASN.1 DUMP output 1. The challengePassword attribute is included to indicate that the CSR should include this value. 2. An ecPublicKey attribute is provided with the value secp384r1 to indicate what kind of key should be submitted. 3. An extensionRequest container with a subjectAltName value containing the name potato@example.com 4. The ecdsaWithSHA384 OID is included to indicate what kind of hash is expected to be used for the self-signature of the PCKS#10 CSR structure. Richardson, et al. Expires 7 March 2025 [Page 13] Internet-Draft CSRAttrs September 2024 <30 66> 0 102: SEQUENCE { <06 09> 2 9: OBJECT IDENTIFIER challengePassword (1 2 840 113549 1 9 7) : (PKCS #9) <30 12> 13 18: SEQUENCE { <06 07> 15 7: OBJECT IDENTIFIER ecPublicKey (1 2 840 10045 2 1) : (ANSI X9.62 public key type) <31 07> 24 7: SET { <06 05> 26 5: OBJECT IDENTIFIER secp384r1 (1 3 132 0 34) : (SECG (Certicom) named elliptic curve) : } : } <30 3B> 33 59: SEQUENCE { <06 09> 35 9: OBJECT IDENTIFIER extensionRequest (1 2 840 113549 1 9 14) : (PKCS #9 via CRMF) <31 2E> 46 46: SET { <30 2C> 48 44: SEQUENCE { <06 03> 50 3: OBJECT IDENTIFIER subjectAltName (2 5 29 17) : (X.509 extension) <01 01> 55 1: BOOLEAN TRUE <04 22> 58 34: OCTET STRING : A0 20 30 1E 06 08 2B 06 . 0...+. : 01 05 05 07 08 0A 0C 12 ........ : 70 6F 74 61 74 6F 40 65 potato@e : 78 61 6D 70 6C 65 2E 63 xample.c : 6F 6D om : } : } : } <06 08> 94 8: OBJECT IDENTIFIER ecdsaWithSHA384 (1 2 840 10045 4 3 3) : (ANSI X9.62 ECDSA algorithm with SHA384) : } Richardson, et al. Expires 7 March 2025 [Page 14] Internet-Draft CSRAttrs September 2024 5.4. Require a public key of a specific size The CSR requires a public key of a specific size 5.4.1. Base64 encoded example The Base64: MCkGCSqGSIb3DQEJBzARBgkqhkiG9w0BAQExBAICEAAGCSqG SIb3DQEBCw== 5.4.2. ASN.1 DUMP output 1. Provide a CSR with an RSA key that's 4096 bits and sign it with sha256 <30 29> 0 41: SEQUENCE { <06 09> 2 9: OBJECT IDENTIFIER challengePassword (1 2 840 113549 1 9 7) : (PKCS #9) <30 11> 13 17: SEQUENCE { <06 09> 15 9: OBJECT IDENTIFIER rsaEncryption (1 2 840 113549 1 1 1) : (PKCS #1) <31 04> 26 4: SET { <02 02> 28 2: INTEGER 4096 : } : } <06 09> 32 9: OBJECT IDENTIFIER sha256WithRSAEncryption (1 2 840 113549 1 1 11) : (PKCS #1) : } 5.5. Require a public key of a specific curve The CSR requires a public key with a specific curve 5.5.1. Base64 encoded example The Base64: MD0GCSqGSIb3DQEJBzASBgcqhkjOPQIBMQcGBSuBBAAiMBIGCSqGSIb3DQEJDjEF BgNVBAUGCCqGSM49BAMD Richardson, et al. Expires 7 March 2025 [Page 15] Internet-Draft CSRAttrs September 2024 5.5.2. ASN.1 DUMP output Provide a CSR with an ECC key from p384, include your serial number, and sign it with sha384. <30 3D> 0 61: SEQUENCE { <06 09> 2 9: OBJECT IDENTIFIER challengePassword (1 2 840 113549 1 9 7) : (PKCS #9) <30 12> 13 18: SEQUENCE { <06 07> 15 7: OBJECT IDENTIFIER ecPublicKey (1 2 840 10045 2 1) : (ANSI X9.62 public key type) <31 07> 24 7: SET { <06 05> 26 5: OBJECT IDENTIFIER secp384r1 (1 3 132 0 34) : (SECG (Certicom) named elliptic curve) : } : } <30 12> 33 18: SEQUENCE { <06 09> 35 9: OBJECT IDENTIFIER extensionRequest (1 2 840 113549 1 9 14) : (PKCS #9 via CRMF) <31 05> 46 5: SET { <06 03> 48 3: OBJECT IDENTIFIER serialNumber (2 5 4 5) : (X.520 DN component) : } : } <06 08> 53 8: OBJECT IDENTIFIER ecdsaWithSHA384 (1 2 840 10045 4 3 3) : (ANSI X9.62 ECDSA algorithm with SHA384) : } 5.6. Require a specific extension The CSR is required to have an EC key, to include a serial number, a friendly name, favorite drink, and be signed with SHA512. 5.6.1. Base64 encoded example The Base64: Richardson, et al. Expires 7 March 2025 [Page 16] Internet-Draft CSRAttrs September 2024 MFQGCSqGSIb3DQEJBzASBgcqhkjOPQIBMQcGBSuBBAAjMCkG CSqGSIb3DQEJDjEcBgNVBAUGCSqGSIb3DQEJFAYKCZImiZPy LGQBBQYIKoZIzj0EAwQ= 5.6.2. ASN.1 DUMP output Provide a CSR with an EC key from sha521, include your serial number, friendly name, and favorite drink, and sign it with sha512 <30 54> 0 84: SEQUENCE { <06 09> 2 9: OBJECT IDENTIFIER challengePassword (1 2 840 113549 1 9 7) : (PKCS #9) <30 12> 13 18: SEQUENCE { <06 07> 15 7: OBJECT IDENTIFIER ecPublicKey (1 2 840 10045 2 1) : (ANSI X9.62 public key type) <31 07> 24 7: SET { <06 05> 26 5: OBJECT IDENTIFIER secp521r1 (1 3 132 0 35) : (SECG (Certicom) named elliptic curve) : } : } <30 29> 33 41: SEQUENCE { <06 09> 35 9: OBJECT IDENTIFIER extensionRequest (1 2 840 113549 1 9 14) : (PKCS #9 via CRMF) <31 1C> 46 28: SET { <06 03> 48 3: OBJECT IDENTIFIER serialNumber (2 5 4 5) : (X.520 DN component) <06 09> 53 9: OBJECT IDENTIFIER : friendlyName (for PKCS #12) (1 2 840 113549 1 9 20) : (PKCS #9 via PKCS #12) <06 0A> 64 10: OBJECT IDENTIFIER '0 9 2342 19200300 100 1 5' : } : } <06 08> 76 8: OBJECT IDENTIFIER ecdsaWithSHA512 (1 2 840 10045 4 3 4) : (ANSI X9.62 ECDSA algorithm with SHA512) : } Richardson, et al. Expires 7 March 2025 [Page 17] Internet-Draft CSRAttrs September 2024 6. Security Considerations The security considerations from EST [RFC7030] section 6 are unchanged. 6.1. Identity and Privacy Considerations An EST server may use this mechanism to instruct the EST client about the identities it should include in the CSR it sends as part of enrollment. The client may only be aware of its IDevID Subject, which includes a manufacturer serial number. The EST server can use this mechanism to tell the client to include a specific fully qualified domain name in the CSR in order to complete domain ownership proofs required by the CA. Additionally, the EST server may deem the manufacturer serial number in an IDevID as personally identifiable information, and may want to specify a new random opaque identifier that the pledge should use in its CSR. This may be desirable if the CA and EST server have different operators. 7. IANA Considerations IANA is asked to allocate two new Object Identifiers: * One (TBD1) from the SMI Security for S/MIME Module Identifier (1.2.840.113549.1.9.16.0) registry for the ASN.1 module: id-mod- critemplate; see Appendix A, and * One (TBD2) from the SMI Security for S/MIME Attributes (1.2.840.113549.1.9.16.2) registry for the Certification Request Information Template (csrinfo) attribute; see Section 3.3 and Appendix A. * One (TBD3) from the PKCS#9 (1 2 840 113549 1 9) registry - TODO COMPLETE THIS ITEM 8. Acknowledgements Corey Bonnell crafted example02 using a different tool, and this helped debug other running code. Carl Wallace provided major parts of the CertificationRequestInfoTemplate syntax declaration. 9. Changelog 10. References 10.1. Normative References Richardson, et al. Expires 7 March 2025 [Page 18] Internet-Draft CSRAttrs September 2024 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC5272] Schaad, J. and M. Myers, "Certificate Management over CMS (CMC)", RFC 5272, DOI 10.17487/RFC5272, June 2008, . [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, . [RFC5912] Hoffman, P. and J. Schaad, "New ASN.1 Modules for the Public Key Infrastructure Using X.509 (PKIX)", RFC 5912, DOI 10.17487/RFC5912, June 2010, . [RFC6268] Schaad, J. and S. Turner, "Additional New ASN.1 Modules for the Cryptographic Message Syntax (CMS) and the Public Key Infrastructure Using X.509 (PKIX)", RFC 6268, DOI 10.17487/RFC6268, July 2011, . [RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed., "Enrollment over Secure Transport", RFC 7030, DOI 10.17487/RFC7030, October 2013, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8994] Eckert, T., Ed., Behringer, M., Ed., and S. Bjarnason, "An Autonomic Control Plane (ACP)", RFC 8994, DOI 10.17487/RFC8994, May 2021, . Richardson, et al. Expires 7 March 2025 [Page 19] Internet-Draft CSRAttrs September 2024 [RFC8995] Pritikin, M., Richardson, M., Eckert, T., Behringer, M., and K. Watsen, "Bootstrapping Remote Secure Key Infrastructure (BRSKI)", RFC 8995, DOI 10.17487/RFC8995, May 2021, . [X.680] ITU-T, "Information technology -- Abstract Syntax Notation One (ASN.1): Specification of basic notation", ITU-T Recommendation X.680, ISO/IEC 8824-1:2021, February 2021, . [X.690] ITU-T, "Information technology -- ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)", ITU-T Recommendation X.690, ISO/IEC 8825-1:2021, February 2021, . 10.2. Informative References [RFC4211] Schaad, J., "Internet X.509 Public Key Infrastructure Certificate Request Message Format (CRMF)", RFC 4211, DOI 10.17487/RFC4211, September 2005, . [RFC8295] Turner, S., "EST (Enrollment over Secure Transport) Extensions", RFC 8295, DOI 10.17487/RFC8295, January 2018, . [RFC8368] Eckert, T., Ed. and M. Behringer, "Using an Autonomic Control Plane for Stable Connectivity of Network Operations, Administration, and Maintenance (OAM)", RFC 8368, DOI 10.17487/RFC8368, May 2018, . [RFC9480] Brockhaus, H., von Oheimb, D., and J. Gray, "Certificate Management Protocol (CMP) Updates", RFC 9480, DOI 10.17487/RFC9480, November 2023, . [RFC9483] Brockhaus, H., von Oheimb, D., and S. Fries, "Lightweight Certificate Management Protocol (CMP) Profile", RFC 9483, DOI 10.17487/RFC9483, November 2023, . Appendix A. ASN.1 Module | RFC EDITOR: Please replace TBD1, TBD2, and TBD3 with the value | assigned by IANA during the publication of this document. Richardson, et al. Expires 7 March 2025 [Page 20] Internet-Draft CSRAttrs September 2024 This appendix provides an ASN.1 module [X.680] for the Certification Request Information Template attribute, and it follows the conventions established in [RFC5911], [RFC5912], and [RFC6268]. CRITemplateModule { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) modules(0) id-mod-critemplate(TBD1) } DEFINITIONS IMPLICIT TAGS ::= BEGIN IMPORTS ATTRIBUTE -- [RFC5911] FROM PKIX-CommonTypes-2009 { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-pkixCommon-02(57) } CertificationRequestInfo -- [RFC5912] FROM PKCS-10 { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-pkcs10-2009(69) } ; aa-certificationRequestInfoTemplate ATTRIBUTE ::= { TYPE CertificationRequestInfoTemplate IDENTIFIED BY id-aa-certificationRequestInfoTemplate } id-aa-certificationRequestInfoTemplate OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) aa(2) csrinfo(TBD2) } CertificationRequestInfoTemplate ::= CertificationRequestInfo END Authors' Addresses Michael Richardson (editor) Sandelman Software Works Email: mcr+ietf@sandelman.ca Richardson, et al. Expires 7 March 2025 [Page 21] Internet-Draft CSRAttrs September 2024 Owen Friel Cisco Email: ofriel@cisco.com Dr. David von Oheimb Siemens Email: dev@ddvo.net Dan Harkins The Industrial Lounge Email: dharkins@lounge.org Richardson, et al. Expires 7 March 2025 [Page 22]