LAMPS Working Group M. Richardson, Ed. Internet-Draft Sandelman Software Works Updates: 7030 (if approved) O. Friel Intended status: Standards Track Cisco Expires: 10 May 2025 D. von Oheimb Siemens D. Harkins The Industrial Lounge 6 November 2024 Clarification and enhancement of RFC7030 CSR Attributes definition draft-ietf-lamps-rfc7030-csrattrs-13 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 10 May 2025. Richardson, et al. Expires 10 May 2025 [Page 1] Internet-Draft CSRAttrs November 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 . . . . . . . . . 9 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. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18 9. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Richardson, et al. Expires 10 May 2025 [Page 2] Internet-Draft CSRAttrs November 2024 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 10.1. Normative References . . . . . . . . . . . . . . . . . . 18 10.2. Informative References . . . . . . . . . . . . . . . . . 19 Appendix A. ASN.1 Module . . . . . . . . . . . . . . . . . . . . 21 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23 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 10 May 2025 [Page 3] Internet-Draft CSRAttrs November 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 [RFC7030], 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 id- ExtensionReq, which has the value 1.2.840.113549.1.9.14. Note that is the same as pkcs-9-at-extensionRequest defined in PKCS#9 [RFC2985]. 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 10 May 2025 [Page 4] Internet-Draft CSRAttrs November 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 particular 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 Alternatively to the piecemeal inclusion of CSR attributes specified in [RFC7030], Section 4.5.2 with its limitations and ambiguities, Appendix B of [RFC8295] describes an approach using a CSR template. An entire CSR object is returned with various fields filled out, and other fields waiting to be filled in. In that approach, a pKCS7PDU attribute includes a Full PKI Data content type [RFC5272] and that in turn includes a CSR or CRMF formatted request (for details see [RFC6268] Sections 5 or 9, respectively). One 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. 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]. Like the approach mentioned before, this method does not properly deal with absent RDNs (encoding them as empty strings), absent subjectPublicKey fields (encoding them as empty BIT STRING), and absent X.509v3 extension values (encoding them as empty OCTET STRING), which may cause issues with strict ASN.1 parsing and decoding. We avoid these drawbacks as follows. Richardson, et al. Expires 10 May 2025 [Page 5] Internet-Draft CSRAttrs November 2024 This specification defines a new Certificate Request Information Template attribute for CsrAttrs (as given in Section 3.2) that is essentially a partially filled in PKCS#10 CSR minus the signature wrapper: CertificationRequestInfoTemplate ::= SEQUENCE { version INTEGER { v1(0) } (v1, ... ), subject NameTemplate OPTIONAL, subjectPKInfo [0] SubjectPublicKeyInfoTemplate {{ PKInfoAlgorithms }} OPTIONAL, attributes [1] Attributes{{ CRIAttributes }} } Appendix A contains all detail. 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 has been made OPTIONAL. It MUST be present if the server places any requirements on the RDNs of the subject name; otherwise it MUST be absent. * RelativeDistinguishedNames (RDNs) in the subject fields are allowed to have no value, which has been achieved by adding OPTIONAL to the value field of SingleAttributeTemplate. If the client is expected to provide an RDN of a certain type such as commonName, the respective RDN MUST be present in the subject field; otherwise it MUST be absent. If the RDN value is present, this means that the client is required to use the given value for the RDN, otherwise the client is expected to fill in the value. SingleAttributeTemplate {ATTRIBUTE:AttrSet} ::= SEQUENCE { type ATTRIBUTE.&id({AttrSet}), value ATTRIBUTE.&Type({AttrSet}{@type}) OPTIONAL } Richardson, et al. Expires 10 May 2025 [Page 6] Internet-Draft CSRAttrs November 2024 * The subjectPKInfo field has been made OPTIONAL. The field MUST be absent if the server places no requirements on the key. Otherwise it MUST be present, and the algorithm field specifies the type of the key pair the client is expected to use. * The subjectPublicKey field contained in SubjectPublicKeyInfoTemplate has been made OPTIONAL because usually it is not needed. In case the server requires use of an RSA key and needs to specify its size, the field MUST be present and contain a dummy public key value of the desired RSA modulus length. Otherwise, the subjectPublicKey MUST be absent. SubjectPublicKeyInfoTemplate{PUBLIC-KEY:IOSet} ::= SEQUENCE { algorithm AlgorithmIdentifier{PUBLIC-KEY, {IOSet}}, subjectPublicKey BIT STRING OPTIONAL } * A new OID id-extensionReqTemplate and the related ExtensionTemplate structure is defined where the extnValue field has been made OPTIONAL. This is only needed to enable specifying partial extensions with values to be filled in by the client; otherwise the id-ExtensionReq OID and the respective value of type ExtensionReq MUST be used. For each extension of type Extension or ExtensionTemplate provided by the server, the client is expected to include an extension of the type given by the extnID. If the critical field is present, the client is expected to use the given value. If the extnValue is present (which is always the case when type Extension is used), the client is required to use the given extension value. Otherwise it is expected to fill in the extension value. If the subjectAltName extension contains the directoryName choice containing the NULL-DN (i.e., an empty sequence of RDNs) or the iPAddress choice with an empty OCTET STRING, this means that the client is expected to fill in the respective GeneralName value. ExtensionTemplate {EXTENSION:ExtensionSet} ::= SEQUENCE { extnID EXTENSION.&id({ExtensionSet}), critical BOOLEAN DEFAULT FALSE, extnValue OCTET STRING (CONTAINING EXTENSION.&ExtnType({ExtensionSet}{@extnID})) OPTIONAL -- contains the DER encoding of the ASN.1 value -- corresponding to the extension type identified -- by extnID when present } The version field of the CertificationRequestInfoTemplate MUST contain v1 (0). Richardson, et al. Expires 10 May 2025 [Page 7] Internet-Draft CSRAttrs November 2024 The attributes field MUST NOT contain multiple at- extensionReqTemplate attributes and MUST NOT contain both extensionRequest and at-extensionReqTemplate 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 extension with DNS name "www.myServer.com" and an empty IP address to be filled in, * the keyUsage extension marked critical with the value digitalSignature and keyAgreement, and * the extKeyUsage extension with value 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 { SEQUENCE { OBJECT IDENTIFIER organizationalUnitName (2 5 4 11) UTF8String "myDept" } } SET { SEQUENCE { OBJECT IDENTIFIER organizationalUnitName (2 5 4 11) UTF8String "myGroup" } } } [0] { SEQUENCE { OBJECT IDENTIFIER ecPublicKey (1 2 840 10045 2 1) Richardson, et al. Expires 10 May 2025 [Page 8] Internet-Draft CSRAttrs November 2024 OBJECT IDENTIFIER secp256r1 (1 2 840 10045 3 1 7) } } [1] { SEQUENCE { OBJECT IDENTIFIER id-extensionReqTemplate (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) } } } } } } 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 CertificationRequestInfoTemplate element. Richardson, et al. Expires 10 May 2025 [Page 9] Internet-Draft CSRAttrs November 2024 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 10 May 2025 [Page 10] Internet-Draft CSRAttrs November 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 10 May 2025 [Page 11] Internet-Draft CSRAttrs November 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 PKCS#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 10 May 2025 [Page 12] Internet-Draft CSRAttrs November 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 PKCS#10 CSR structure. Richardson, et al. Expires 10 May 2025 [Page 13] Internet-Draft CSRAttrs November 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 10 May 2025 [Page 14] Internet-Draft CSRAttrs November 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 10 May 2025 [Page 15] Internet-Draft CSRAttrs November 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 10 May 2025 [Page 16] Internet-Draft CSRAttrs November 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 10 May 2025 [Page 17] Internet-Draft CSRAttrs November 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 * 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 Appendix A * One (TBD3) from the PKCS#9 (1 2 840 113549 1 9) registry for the id-extensionReqTemplate AttributeType; see Section 3.3 and Appendix A 8. Acknowledgments 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 10 May 2025 [Page 18] Internet-Draft CSRAttrs November 2024 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [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, . [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, . 10.2. Informative References [RFC2985] Nystrom, M. and B. Kaliski, "PKCS #9: Selected Object Classes and Attribute Types Version 2.0", RFC 2985, DOI 10.17487/RFC2985, November 2000, . [RFC4211] Schaad, J., "Internet X.509 Public Key Infrastructure Certificate Request Message Format (CRMF)", RFC 4211, DOI 10.17487/RFC4211, September 2005, . Richardson, et al. Expires 10 May 2025 [Page 19] Internet-Draft CSRAttrs November 2024 [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, . [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, . [RFC8994] Eckert, T., Ed., Behringer, M., Ed., and S. Bjarnason, "An Autonomic Control Plane (ACP)", RFC 8994, DOI 10.17487/RFC8994, May 2021, . [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, . [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, . [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, . Richardson, et al. Expires 10 May 2025 [Page 20] Internet-Draft CSRAttrs November 2024 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. 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 -- from [RFC5912] SupportedAttributes FROM PKIX1Explicit-2009 { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-pkix1-explicit-02(51)} EXTENSION 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) } PUBLIC-KEY, AlgorithmIdentifier{} FROM AlgorithmInformation-2009 { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-algorithmInformation-02(58)} CertExtensions FROM PKIX1Implicit-2009 { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-pkix1-implicit-02(59)} ATTRIBUTE, Attributes{}, CRIAttributes, PKInfoAlgorithms 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 ::= Richardson, et al. Expires 10 May 2025 [Page 21] Internet-Draft CSRAttrs November 2024 { 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) } -- like CertificationRequestInfo but OPTIONAL subject, subjectPKInfo CertificationRequestInfoTemplate ::= SEQUENCE { version INTEGER { v1(0) } (v1, ... ), subject NameTemplate OPTIONAL, subjectPKInfo [0] SubjectPublicKeyInfoTemplate {{ PKInfoAlgorithms }} OPTIONAL, attributes [1] Attributes{{ CRIAttributes }} } -- like Name, but with OPTIONAL RDN values NameTemplate ::= CHOICE { -- only one possibility for now -- rdnSequence RDNSequenceTemplate } RDNSequenceTemplate ::= SEQUENCE OF RelativeDistinguishedNameTemplate RelativeDistinguishedNameTemplate ::= SET SIZE (1 .. MAX) OF SingleAttributeTemplate { {SupportedAttributes} } -- like SingleAttribute, but with OPTIONAL value SingleAttributeTemplate{ATTRIBUTE:AttrSet} ::= SEQUENCE { type ATTRIBUTE.&id({AttrSet}), value ATTRIBUTE.&Type({AttrSet}{@type}) OPTIONAL } -- like SubjectPublicKeyInfo, but with OPTIONAL subjectPublicKey SubjectPublicKeyInfoTemplate{PUBLIC-KEY:IOSet} ::= SEQUENCE { algorithm AlgorithmIdentifier{PUBLIC-KEY, {IOSet}}, subjectPublicKey BIT STRING OPTIONAL } id-extensionReqTemplate AttributeType ::= {pkcs-9 TBD3} -- like extensionRequest, but with OPTIONAL Extension extnValues -- original definition was in PKCS#9 RFC 2985 section 5.4.2 at-extensionReqTemplate ATTRIBUTE ::= { TYPE ExtensionReqTemplate IDENTIFIED BY id-extensionReqTemplate } ExtensionReqTemplate ::= ExtensionTemplates{{CertExtensions}} Richardson, et al. Expires 10 May 2025 [Page 22] Internet-Draft CSRAttrs November 2024 -- like Extensions, but with OPTIONAL extnValue ExtensionTemplates{EXTENSION:ExtensionSet} ::= SEQUENCE SIZE (1..MAX) OF ExtensionTemplate{{ExtensionSet}} -- like Extension, but with OPTIONAL extnValue 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 -- contains the DER encoding of the ASN.1 value -- corresponding to the extension type identified -- by extnID when present } END Authors' Addresses Michael Richardson (editor) Sandelman Software Works Email: mcr+ietf@sandelman.ca 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 10 May 2025 [Page 23]