Internet-Draft | CSRAttrs | November 2024 |
Richardson, et al. | Expires 10 May 2025 | [Page] |
- Workgroup:
- LAMPS Working Group
- Internet-Draft:
- draft-ietf-lamps-rfc7030-csrattrs-13
- Updates:
- 7030 (if approved)
- Published:
- Intended Status:
- Standards Track
- Expires:
Clarification and enhancement of RFC7030 CSR Attributes definition
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.¶
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.¶
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.¶
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]:¶
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.¶
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 madeOPTIONAL
. 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 addingOPTIONAL
to thevalue
field ofSingleAttributeTemplate
. If the client is expected to provide an RDN of a certain type such ascommonName
, the respective RDN MUST be present in thesubject
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 }¶
-
The
subjectPKInfo
field has been madeOPTIONAL
. The field MUST be absent if the server places no requirements on the key. Otherwise it MUST be present, and thealgorithm
field specifies the type of the key pair the client is expected to use.¶ -
The
subjectPublicKey
field contained inSubjectPublicKeyInfoTemplate
has been madeOPTIONAL
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, thesubjectPublicKey
MUST be absent.¶
SubjectPublicKeyInfoTemplate{PUBLIC-KEY:IOSet} ::= SEQUENCE { algorithm AlgorithmIdentifier{PUBLIC-KEY, {IOSet}}, subjectPublicKey BIT STRING OPTIONAL }¶
-
A new OID
id-extensionReqTemplate
and the relatedExtensionTemplate
structure is defined where theextnValue
field has been madeOPTIONAL
. This is only needed to enable specifying partial extensions with values to be filled in by the client; otherwise theid-ExtensionReq
OID and the respective value of typeExtensionReq
MUST be used.
For each extension of typeExtension
orExtensionTemplate
provided by the server, the client is expected to include an extension of the type given by theextnID
. If thecritical
field is present, the client is expected to use the given value. If theextnValue
is present (which is always the case when typeExtension
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 thedirectoryName
choice containing theNULL-DN
(i.e., an empty sequence of RDNs) or theiPAddress
choice with an emptyOCTET STRING
, this means that the client is expected to fill in the respectiveGeneralName
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).¶
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) 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.¶
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.¶
<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==¶
5.2.2. ASN.1 DUMP output
-
The challengePassword attribute is included to indicate that the CSR should include this value.¶
-
An ecPublicKey attribute is provided with the value secp384r1 to indicate what kind of key should be submitted.¶
-
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.¶
-
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) : }¶
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
-
The challengePassword attribute is included to indicate that the CSR should include this value.¶
-
An ecPublicKey attribute is provided with the value secp384r1 to indicate what kind of key should be submitted.¶
-
An extensionRequest container with a subjectAltName value containing the name potato@example.com¶
-
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 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) : }¶
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
-
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¶
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:¶
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) : }¶
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.¶
10. References
10.1. Normative References
- [RFC2119]
- Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/rfc/rfc2119>.
- [RFC5911]
- Hoffman, P. and J. Schaad, "New ASN.1 Modules for Cryptographic Message Syntax (CMS) and S/MIME", RFC 5911, DOI 10.17487/RFC5911, , <https://www.rfc-editor.org/rfc/rfc5911>.
- [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, , <https://www.rfc-editor.org/rfc/rfc5912>.
- [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, , <https://www.rfc-editor.org/rfc/rfc6268>.
- [RFC7030]
- Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed., "Enrollment over Secure Transport", RFC 7030, DOI 10.17487/RFC7030, , <https://www.rfc-editor.org/rfc/rfc7030>.
- [RFC8174]
- Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/rfc/rfc8174>.
- [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, , <https://www.itu.int/rec/T-REC-X.680>.
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, , <https://www.rfc-editor.org/rfc/rfc2985>.
- [RFC4211]
- Schaad, J., "Internet X.509 Public Key Infrastructure Certificate Request Message Format (CRMF)", RFC 4211, DOI 10.17487/RFC4211, , <https://www.rfc-editor.org/rfc/rfc4211>.
- [RFC5272]
- Schaad, J. and M. Myers, "Certificate Management over CMS (CMC)", RFC 5272, DOI 10.17487/RFC5272, , <https://www.rfc-editor.org/rfc/rfc5272>.
- [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, , <https://www.rfc-editor.org/rfc/rfc5280>.
- [RFC8295]
- Turner, S., "EST (Enrollment over Secure Transport) Extensions", RFC 8295, DOI 10.17487/RFC8295, , <https://www.rfc-editor.org/rfc/rfc8295>.
- [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, , <https://www.rfc-editor.org/rfc/rfc8368>.
- [RFC8994]
- Eckert, T., Ed., Behringer, M., Ed., and S. Bjarnason, "An Autonomic Control Plane (ACP)", RFC 8994, DOI 10.17487/RFC8994, , <https://www.rfc-editor.org/rfc/rfc8994>.
- [RFC8995]
- Pritikin, M., Richardson, M., Eckert, T., Behringer, M., and K. Watsen, "Bootstrapping Remote Secure Key Infrastructure (BRSKI)", RFC 8995, DOI 10.17487/RFC8995, , <https://www.rfc-editor.org/rfc/rfc8995>.
- [RFC9480]
- Brockhaus, H., von Oheimb, D., and J. Gray, "Certificate Management Protocol (CMP) Updates", RFC 9480, DOI 10.17487/RFC9480, , <https://www.rfc-editor.org/rfc/rfc9480>.
- [RFC9483]
- Brockhaus, H., von Oheimb, D., and S. Fries, "Lightweight Certificate Management Protocol (CMP) Profile", RFC 9483, DOI 10.17487/RFC9483, , <https://www.rfc-editor.org/rfc/rfc9483>.
- [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, , <https://www.itu.int/rec/T-REC-X.690>.
Appendix A. ASN.1 Module
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 ::= { 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}} -- 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¶