SIDR G. Huston
Internet-Draft R. Loomans
Intended status: Best Current G. Michaelson
Practice APNIC
Expires: December 21, 2006 June 19, 2006
A Profile for X.509 PKIX Resource Certificates
draft-ietf-sidr-res-certs-01.txt
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Copyright Notice
Copyright (C) The Internet Society (2006).
Abstract
This document defines a profile for X.509 certificates for the
purposes of supporting validation of assertions of "right-to- use" of
an Internet Number Resource (IP Addresses and Autonomous System
Numbers). This profile is used to convey the authorization of the
subject to be regarded as the current unique controlled of the IP
addresses and AS numbers that are described in a Resource
Certificate.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Describing Resources in Certificates . . . . . . . . . . . . . 5
3. Resource Certificate Fields . . . . . . . . . . . . . . . . . 6
3.1. Version . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.2. Serial number . . . . . . . . . . . . . . . . . . . . . . 6
3.3. Signature Algorithm . . . . . . . . . . . . . . . . . . . 6
3.4. Issuer . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.5. Subject . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.6. Valid From . . . . . . . . . . . . . . . . . . . . . . . . 6
3.7. Valid To . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.8. Subject Public Key Info . . . . . . . . . . . . . . . . . 7
3.9. Resource Certificate Version 3 Extension Fields . . . . . 7
3.9.1. Basic Constraints . . . . . . . . . . . . . . . . . . 7
3.9.2. Subject Key Identifier . . . . . . . . . . . . . . . . 8
3.9.3. Authority Key Identifier . . . . . . . . . . . . . . . 8
3.9.4. Key Usage . . . . . . . . . . . . . . . . . . . . . . 8
3.9.5. CRL Distribution Points . . . . . . . . . . . . . . . 9
3.9.6. Authority Information Access . . . . . . . . . . . . . 9
3.9.7. Subject Information Access . . . . . . . . . . . . . . 10
3.9.8. Certificate Policies . . . . . . . . . . . . . . . . . 11
3.9.9. Subject Alternate Name . . . . . . . . . . . . . . . . 11
3.9.10. IP Resources . . . . . . . . . . . . . . . . . . . . . 11
3.9.11. AS Resources . . . . . . . . . . . . . . . . . . . . . 11
4. Resource Certificate Revocation List Profile . . . . . . . . . 11
4.1. Version . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.2. Issuer Name . . . . . . . . . . . . . . . . . . . . . . . 12
4.3. This Update . . . . . . . . . . . . . . . . . . . . . . . 12
4.4. Next Update . . . . . . . . . . . . . . . . . . . . . . . 12
4.5. Signature . . . . . . . . . . . . . . . . . . . . . . . . 12
4.6. Revoked Certificate List . . . . . . . . . . . . . . . . . 13
4.6.1. Serial Number . . . . . . . . . . . . . . . . . . . . 13
4.6.2. Revocation Date . . . . . . . . . . . . . . . . . . . 13
4.7. CRL Extensions . . . . . . . . . . . . . . . . . . . . . . 13
4.7.1. Authority Key Identifier . . . . . . . . . . . . . . . 13
4.7.2. CRL Number . . . . . . . . . . . . . . . . . . . . . . 13
5. Resource Certificate Request Profile . . . . . . . . . . . . . 14
5.1. Resource Certificate Request Template Fields . . . . . . . 14
5.2. Resource Certificate Request Control Fields . . . . . . . 17
6. Resource Certificate Validation . . . . . . . . . . . . . . . 18
6.1. Trust Anchors for Resource Certificates . . . . . . . . . 19
6.2. Resource Extension Validation . . . . . . . . . . . . . . 20
6.3. Resource Certificate Path Validation . . . . . . . . . . . 20
7. Security Considerations . . . . . . . . . . . . . . . . . . . 22
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 22
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10. Normative References . . . . . . . . . . . . . . . . . . . . . 22
Appendix A. Example Resource Certificate . . . . . . . . . . . . 23
Appendix B. Example Certificate Revocation List . . . . . . . . . 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 25
Intellectual Property and Copyright Statements . . . . . . . . . . 26
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1. Introduction
This document defines a profile for X.509 certificates for use in the
context of Resources Certificates. Resource Certificates are X.509
certificates that conform to the PKIX profile [RFC3280] and to this
additional profile, and attest that the subject has the "right-to-
use" a listed set of IP addresses and Autonomous Numbers.
A Resource Certificate describes an action by an Issuer that binds a
list of IP address blocks and AS numbers to the Subject of a
certificate, identified by the unique association of the Subject's
private key with the public key contained in the Resource
Certificate.
In the context of the public Internet it is intended that Resource
Certificates are used in a manner that is aligned to the public
number resource distribution function, Specifically, when a number
resource is allocated or assigned by a Registry to an entity, this
allocation is described by a Resource Certificate issued by the
Registry with a subject corresponding to the entity that is the
recipient of this assignment or allocation. This corresponds to a
hierarchical PKI structure, where Resource Certificates are only
issued in one 'direction' and there is a single unique path from a
"Root CA" to any valid certificate.
Validation of a certificate in such a hierarchical PKI can be
undertaken by creating a valid issuer - subject chain from the trust
anchor allocation authorities to the certificate [RFC4158].
Resource Certificates may be used in the context of secure inter-
domain routing protocols to convey a right-to-use of an IP number
resource that is being passed within the routing protocol, to verify
legitimacy and correctness of routing information. Related use
contexts include validation of access to Internet Routing Registries
for nominated routing objects, validation of routing requests, and
detection of potential unauthorized used of IP addresses.
This profile defines those fields that are used in a Resource
Certificate that MUST be present for the certificate to be valid.
Relying Parties SHOULD check that a Resource Certificate conforms to
this profile as a requisite for validation of a Resource Certificate.
1.1. Terminology
It is assumed that the reader is familiar with the terms and concepts
described in "Internet X.509 Public Key Infrastructure Certificate
and Certificate Revocation List (CRL) Profile" [RFC3280], "X.509
Extensions for IP Addresses and AS Identifiers" [RFC3779], "Internet
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Protocol" [RFC0791], "Internet Protocol Version 6 (IPv6) Addressing
Architecture" [RFC4291], "Internet Registry IP Allocation Guidelines"
[RFC2050], and related regional Internet registry address management
policy documents.
The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119.
2. Describing Resources in Certificates
The framework for describing an association between the subject of a
certificate and the resources currently under the subject's current
control is described in [RFC3779].
There are three aspects of this resource extension that are noted in
this profile:
1. RFC 3779 notes that this resource extension SHOULD be a CRITICAL
extension to the X.509 Certificate. This Resource Certificate
profile further defines that the use of this certificate
extension MUST be used and MUST be marked as CRITICAL.
2. RFC 3779 defines a sorted canonical form of describing a resource
set, with maximal spanning ranges and maximal spanning prefix
masks as appropriate. All valid certificates in this profile
MUST use this sorted canonical form of resource description
3. A test of the resource extension in the context of certificate
unique value token within the context of certificates issued by
the validity includes the first condition that the resources
described in the Issuer's resource extension must encompass those
of the Subject's resource extension. In this context "encompass"
allows for the Issuer's resource set to be the same as, or a
strict superset of, any subject's resource set. Certificate
validity in the context of this profile also includes a second
condition that no two (or more) certificates issued by a single
Issuer to two (or more) different subjects have a non-null
intersection of resources. In other words an Issuer can certify
at most one unique subject as the unique holder of a right-to-use
for any particular resource.
This implies that a test of certificate validity implies that there
exists a set of valid certificates in an issuer-subject chain from
one, and only one, trust anchor to the certificate in question, and
that the resource extensions from the trust anchor to the certificate
form a sequence of encompassing relationships.
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3. Resource Certificate Fields
A Resource Certificate is a valid X.509 v3 public key certificate,
consistent with the PKIX profile [RFC3280], containing the fields
listed in this section. Unless specifically noted as being OPTIONAL,
all the fields listed here MUST be present, and any other field MUST
NOT appear in a conforming Resource Certificate. Where a field value
is specified here this value MUST be used in conforming Resource
Certificates.
3.1. Version
Resource Certificates are X.509 Version 3 certificates. This field
MUST be present, and the Version MUST be 3 (i.e. the value of this
field is 2).
3.2. Serial number
The serial number value is a positive integer that is unique per
Issuer.
3.3. Signature Algorithm
This field describes the algorithm used to compute the signature on
this certificate. This profile uses SHA-256 with RSA
(sha256WithRSAEncryption), and the value for this field MUST be the
OID value 1.2.840.113549.1.1.11 [RFC4055].
3.4. Issuer
This field identifies the entity that has signed and issued the
certificate. The value of this field is an X.501 name.
3.5. Subject
This field identifies the entity to whom the resource has been
allocated / assigned. The value of this field is an X.500 name. In
this profile the subject name is determined by the Issuer.
This field MUST be non-empty.
3.6. Valid From
The starting time at which point the certificate is valid. In this
profile the "Valid From" time is to be no earlier than the time of
certificate generation. As per Section 4.1.2.5 of [RFC3280],
Certificate Authorities (CAs) conforming to this profile MUST always
encode the certificate's "Valid From" date through the year 2049 as
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UTCTime, and dates in 2050 or later MUST be encoded as
GeneralizedTime. These two time formats are defined in [RFC3280].
3.7. Valid To
The Valid To time is the date and time at which point in time the
certificate's validity ends. It represents the anticipated lifetime
of the resource allocation / assignment arrangement between the
Issuer and the Subject. As per Section 4.1.2.5 of [RFC3280], CAs
conforming to this profile MUST always encode the certificate's
"Valid To" date through the year 2049 as UTCTime, and dates in 2050
or later MUST be encoded as GeneralizedTime. These two time formats
are defined in [RFC3280].
3.8. Subject Public Key Info
This field specifies the subject's public key and the algorithm with
which the key is used. The public key algorithm MUST be RSA, and
thus the OID for the algorithm is 1.2.840.113549.1.1.1. A minimum
key size of 1024 bits is mandated in this profile. Regional Registry
CAs MUST use a key size of 2048 bits.
[Note - not for publication. One alternative option is to specify
"no less than 2048 bits" and allow for longer key sizes. On the
other hand it may be preferable to move to EC-DSA instead of RSA, in
which case allowing for the option of longer RSA key sizes may be
considered inappropriate.]
3.9. Resource Certificate Version 3 Extension Fields
As noted in Section 4.2 of [RFC3280], each extension in a certificate
is designated as either critical or non-critical. A certificate
using system MUST reject the certificate if it encounters a critical
extension it does not recognize; however, a non-critical extension
MAY be ignored if it is not recognized [RFC3280].
The following X.509 V3 extensions MUST be present in a conforming
Resource Certificate.
3.9.1. Basic Constraints
The basic constraints extension identifies whether the subject of the
certificate is a CA and the maximum depth of valid certification
paths that include this certificate.
The Issuer determines whether the cA boolean is set. If this bit is
set, then it indicates that the Subject is allowed to issue resources
certificates within this overall framework (i.e. the subject is
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permitted be a CA).
The Path Length Constraint is not specified in this profile and MUST
NOT be present.
The Basic Constraints extension field is a critical extension in the
Resource Certificate profile, and MUST be present.
[note - not for publication. It is unclear whether the CA bit should
be set on in all cases.
3.9.2. Subject Key Identifier
The subject key identifier extension provides a means of identifying
certificates that contain a particular public key. To facilitate
certification path construction, this extension MUST appear in all
Resource Certificates. This extension is non-critical.
The value of the subject key identifier MUST be the value placed in
the key identifier field of the Authority Key Identifier extension of
certificates issued by the subject of this certificate.
The Key Identifier used here is the 160-bit SHA-1 hash of the value
of the DER-encoded ASN.1 bit string of the subject public key, as
described in Section 4.2.1.2 of[RFC3280].
3.9.3. Authority Key Identifier
The subject key identifier extension provides a means of identifying
certificates that are signed by a particular issuer's private key, by
providing a hash value of the corresponding Issuer's public key. To
facilitate path construction, this extension MUST appear in all
Resource Certificates. The keyIdentifier subfield MUST be present.
The authorityCertIssuer and authorityCertSerialNumber subfields MAY
be present. This extension is non-critical.
The Key Identifier used here is the 160-bit SHA-1 hash of the value
of the DER-encoded ASN.1 bit string of the issuer's public key, as
described in Section 4.2.1.1 of [RFC3280].
3.9.4. Key Usage
This describes the purpose of the certificate. This is a critical
extension, and it MUST be present.
In certificates issued to CAs only the keyCertSign and CRLSign bits
are set to TRUE. In end-entity certificates the digitialSignature
bit MUST be set and MUST be the only bit set to TRUE.
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3.9.5. CRL Distribution Points
This field (CRLDP) identifies the location(s) of the CRL(s)
associated with certificates issued by this Issuer. This profile
uses the URI form of object identification. The preferred URI access
mechanism is a single "rsync" URL that references a single inclusive
CRL for each issuer.
In this profile the certificate issuer is also the CRL issuer,
implying at the CRLIssuer subfield MUST be omitted, and the
distributionPoint subfield MUST be present. The Reasons subfield
MUST be omitted.
The distributionPoint MUST contain general names, and MUST NOT
contain a nameRelativeToCRLIssuer. The type of the general name MUST
be of type URI. Furthermore, as the scope of the CRL is all
certificates issued by this issuer, the sequence of distributionPoint
values MUST contain only a single DistributionPointName set. The
DistributionPointName set MAY contain more than one URI value. An
rsync URI MUST be present in the DistributionPointName set.
This extension MUST be present and it is non-critical.
[NOTE - not for publication. The reason for the specification of an
RSYNC URI as a MUST in this profile is to ensure that relying parties
who wish to maintain a local copy of a synchronized repository are
not forced to maintain a retrieval capability using a potentially
unbounded set of URI types. The profile is attempting to ensure that
rsync should be all that is required to perform a repository
synchronization operation. A more restrictive potential condition
here (and also in the SIA and AIA extensions) is that one and only
one RSYNC URI is permitted. This would reduce some of the potential
variations in certificates and also stress that certificate access
and use by relying parties is critically dependent on RSYNC access,
and that other forms of access are not necessarily available to
relying parties.]
3.9.6. Authority Information Access
This field (AIA) identifies the location of all certificates that are
issued by this Issuer that are signed with the Issuer's private key
that signed this certificate. This profile uses a URI form of object
identification. The preferred URI access mechanisms is "rsync", and
an rsync URI MUST be specified with an accessMethod value of id-ad-
caIssuers. Other access method URIs MAY also be included in the
value sequence of this extension.
This field MUST be present, and is non-critical.
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[Note - not for publication rfc3280 defines only two OIDs for the
access method, id-ad-caIssuers and id-ad-ocsp. It would appear that
id-ad-ocsp is not relevant here in that OCSP is not included as part
of the resource certificate profile - which leaves id-ad-caIssuers.
The text in 4.2.2.1 of RFC3280 notes that: "the id-ad-caIssuers OID
is used when the additional information lists CAs that have issued
certificates superior to the CA that issued the certificate
containing this extension. The referenced CA issuers description is
intended to aid certificate users in the selection of a certification
path that terminates at a point trusted by the certificate user"
However there is no intention to require that such a list be included
in this subfield in this profile. The question is: What accessMethod
OID should be used here in the Access Description?]
3.9.7. Subject Information Access
This field (SIA) identifies the location of information and services
relating to the subject of the certificate in which the SIA extension
appears that relate to the subject public key that is certified in
this certificate. Where the Subject is a CA for Resource
Certificates this information and service collection will include all
current valid certificates that have been issued by this subject that
are signed with the subject's corresponding private key. This
profile uses a URI form of location identification. The preferred
URI access mechanism is "rsync", and an rsync URI SHOULD be
specified, with an access method value of id-ad-caRepository when the
subject of the certificate is a CA. Other access method URIs MAY
also be included in the value sequence of this extension.
This field MUST be present when the subject is a CA, and is non-
critical. Where the subject is not a CA this field MUST NOT be
present.
[Note - not for publication. RFC3280 defines only two OIDs for the
access method, id-ad-caRepository and id-ad-timeStamping, with the
difference being whether the subject is a CA or not. The access
method id-ad-caRepository appears to be appropriate where the subject
is a CA. Where the subject is NOT a CA would it be useful to have
the SIA extension point to where the subject stores digital objects
that have been signed by the subject? If this were considered to be
desirable, then the id-ad-timeStamping appears to be inappropriate in
this context. The general question is: What accessMethod OID should
be used here in the Access Description? The approach currently used
in this draft is that SIA should only be present for CAs and must be
absent in the case of End Entity certificates.]
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3.9.8. Certificate Policies
This extension MUST reference the Resource Certificate Policy, using
the OID Policy Identifier value of "1.3.6.1.5.5.7.14.2". This field
MUST be present and MUST contain only this value for Resource
Certificates.
PolicyQualifiers MUST NOT be used in this profile.
This extension MUST be present and it is critical.
3.9.9. Subject Alternate Name
This is an optional extension, and MAY contain an X.501 Name as
supplied by the subject in the Certificate Request or as assigned by
the Issuer CA.
3.9.10. IP Resources
This field contains the list of IP address resources as per
[RFC3779]. The value may specify the "inherit" element for a
particular AFI value and an optional SAFI value. All Resource
Certificates MUST include an IP Resources extension, an AS Resources
extension, or both extensions.
This extension, if present, MUST be marked critical.
3.9.11. AS Resources
This field contains the list of AS number resources as per [RFC3779],
or may specify the "inherit" element. All Resource Certificates MUST
include an IP Resources extension, an AS Resources extension, or both
extensions. RDI values are NOT supported in this profile and MUST
NOT be used.
This extension, if present, MUST be marked critical.
4. Resource Certificate Revocation List Profile
Each Resource CA MUST issue a version 2Certificate Revocation List
(CRL), consistent with [RFC3280]. The CRL issuer is the CA, and no
indirect CRLs are supported in this profile. The scope of the CRL
MUST be "all certificates issued by this CA". The contents of the
CRL are a list of all unexpired certificates issued by the CA that
have been revoked by the CA.
An entry MUST NOT be removed from the CRL until it appears on one
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regularly scheduled CRL issued beyond the revoked certificate's
validity period.
This profile does not allow issuance of Delta CRLs.
The profile does not allow the issuance of multiple current CRLs with
different scope by a single CA.
No CRL fields other than those listed below are allowed in CRLs
issued under this profile. Unless otherwise indicated, these fields
MUST be present in the CRL. Where two or more CRLs issued by a
single CA are present in a certificate repository, the CRL with the
highest value of the "CRL Number" field supersedes all other extant
CRLs issued by this CA..
4.1. Version
Resource Certificate Revocation Lists are Version 2 certificates (the
integer value of this field is 1).
4.2. Issuer Name
The value of this field is the X.501 name of the issuing CA who is
also the signer of the CRL, and is identical to the Issuer name in
the Resource Certificates.
4.3. This Update
This is the date and time that this CRL was issued. The value of
this field MUST be encoded as UTCTime for dates through the year
2049, and MUST be encoded as GeneralizedTime for dates in the year
2050 or later.
4.4. Next Update
This is the date and time by which the next CRL will be issued. The
value of this field MUST be encoded as UTCTime for dates through the
year 2049, and MUST be encoded as GeneralizedTime for dates in the
year 2050 or later.
4.5. Signature
This field contains the algorithm used to sign this CRL. The
signature algorithm MUST be SHA-256 with RSA. This field MUST be
present.
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4.6. Revoked Certificate List
When there are no revoked certificates, then the revoked certificate
list MUST be absent.
For each revoked resource certificate ONLY the following fields MUST
be present. No CRL entry extensions are supported in this profile.
4.6.1. Serial Number
The serial number of the revoked certificate.
4.6.2. Revocation Date
The time the certificate was revoked. This time SHOULD NOT be a
future date. The value of this field MUST be encoded as UTCTime for
dates through the year 2049, and MUST be encoded as GeneralizedTime
for dates in the year 2050 or later.
4.7. CRL Extensions
The X.509 v2 CRL format allows extensions to be placed in a CRL. The
following extensions are supported in this profile, and MUST be
present in a CRL.
4.7.1. Authority Key Identifier
The authority key identifier extension provides a means of
identifying the public key corresponding to the private key used to
sign a CRL. Conforming CRL issuers MUST use the key identifier
method. The syntax for this CRL extension is defined in section
4.2.1.1 of [RFC3280].
This extension is non-critical.
4.7.2. CRL Number
The CRL Number extension conveys a monotonically increasing sequence
number for a given CA. This extension allows users to easily
determine when a particular CRL supersedes another CRL. The higher
CRL Number value supersedes all other CRLs issued by the CA within
the scope of this profile.
This extension is non-critical.
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5. Resource Certificate Request Profile
This profile refines the specification in [RFC4211], as it relates to
Resource Certificates. A Certificate Request Message object,
formatted according to the Certificate Request Message Format (CRMF),
is passed to a Certificate Authority as the initial step in issuing a
certificate.
[Note - not for publication. RFC2986 references PKCS #10:
Certification Request Syntax Specification, Version 1.7. Given the
relative wide support of CMC, the extension of PKCS#10 that is
roughly equivalent to CMP, then it would appear that a CMC profile
should also be included here. It is unclear at this point whether a
PCKS#10 profile is also necessary in this profile.]
This request may be conveyed to the CA via a Registration Authority
(RA), acting under the direction of a Subject.
[Note - not for publication: There are no profile-based
qualifications regarding Proof-of-Possession. This may be refined in
subsequent iterations of this draft.]
5.1. Resource Certificate Request Template Fields
This profile applies the following additional constraints to fields
that may appear in a Certificate Request Template:
Version
This field MAY be absent, or MAY specify the request of a Version
3 Certificate.
SerialNumber
As per [RFC4211], this field is assigned by the CA and MUST be
omitted in this profile.
SigningAlgorithm
As per [RFC4211], this field is assigned by the CA and MUST be
omitted in this profile.
Issuer
This field is assigned by the CA and MUST be omitted in this
profile.
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Validity
This field MAY be omitted. If omitted, the CA will issue a
Certificate with Validity dates as determined by the CA. If
specified, then the CA MAY override the requested values with
dates as determined by the CA.
Subject As the subject name is assigned by the CA, this field MAY be
omitted, in which case the subject name will be generated by the
CA. If specified, the CA SHOULD consider this as the subject's
suggestion, but the CA is NOT bound to honour this suggestion.
PublicKey
This field MUST be present.
This profile applies the following additional constraints to X509 v3
Certificate extension fields that may appear in a Certificate
Request:
BasicConstraints
If this is omitted then this field is assigned by the CA.
The Path Length Constraint is not supported in this Resource
Certificate Profile, and this field MUST be omitted in this
profile.
The CA MAY honour the SubjectType CA bit set to on. If this bit
is set, then it indicates that the Subject is allowed to issue
resources certificates within this overall framework.
The CA MAY honour the SubjectType CA bit set of off (End Entity
certificate request).
[Note - not for publication. There are some potential variants on
this model, where the CA bit may be considered as being set in all
circumstances. For example, if the generation of signed resource
objects, such as routing origination authorities requires the
generation of special purpose resource certificates whose validity
dates are implicitly the validity dates of the associated
authority, then the subject needs to be able to issue certificates
- i.e. there is a CA requirement. In this version of the draft
this is left as a subject suggestion in the request that the CA
may, or may not, honor in the issued certificate. In this model
all the entities are CAs, except for the users of ROA signing
shadow certs. In both cases, the CA knows the intended purpose
(i.e. issue to others: CA, issue shadow to yourself: non-CA). ]
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SubjectKeyIdentifier
This field is assigned by the CA and MUST be omitted in this
profile.
AuthorityKeyIdentifier
This field is assigned by the CA and MUST be omitted in this
profile.
KeyUsage
The CA MAY honor KeyUsage extensions of CertificateSigning and
CRLSigning if present, as long as this is consistent with the
BasicConstraints SubjectType subfield, when specified.
CRLDistributionPoints
This field MAY be honoured by the CA on the condition that the CA
issues a certificate with the BasicConstraints SubjectType CA bit
set and the KeyUsage set to CertificateSigning and CRLSigning.
If specified, this field contains a sequence of URIs that
references a CRL that will be published by the subject for
subordinate certificates. This sequence MUST include a rsync URI.
This field MAY be honoured by the CA if present.
If this field is omitted and KeyUsage is set to CertificateSigning
then the CA MUST generate a CRLDistributionPoint URL based on out-
of-band information that has been passed between the CA and the
requester.
[Note - not for publication. The issue of where and how to
specify where the subject will publish the CRL if the CA bit is
set and honored by the issuer is described here as information
that is either provided in this field in the certificate request
or provided via an "out-of-band" exchange. An alternative is to
say that this field MUST be provided if the CA bit is set in the
request.]
AuthorityInformationAccess
This field is assigned by the CA and MUST be omitted in this
profile.
SubjectInformationAccess
This field MAY be honoured by the CA on the condition that the CA
issues a certificate with the BasicConstraints SubjectType CA bit
set and the KeyUsage set to CertificateSigning and CRLSigning.
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If specified, this field contains a URI of the form of a single
rsync URL that references a single publication point that will be
used by the subject for all certificates that published by the
subject for subordinate certificates, and MUST be honoured by the
CA.
If this field is omitted and KeyUsage is set to CertificateSigning
then the CA MUST generate a SIA URL based on out-of-band
information that has been passed between the CA and the requester.
[Note not for publication - the same considerations with respect
to the CRL DistributionPoints apply to this field as well. i.e. if
this field is missing than it is also an option for the Issuer to
deny the request and not issue a certificate if the issued
certificate was to have the CA bit set.]
CertificatePolicies
This field is assigned by the CA and MUST be omitted in this
profile.
SubjectAlternateName
This field MAY be present, and the CA MAY use this as the
SubjectAltName in the issued Certificate.
IPResources
This field is assigned by the CA and MUST be omitted in this
profile.
ASResources
This field is assigned by the CA and MUST be omitted in this
profile.
With the exception of the publicKey field, the CA is permitted to
alter any requested field.
5.2. Resource Certificate Request Control Fields
The following control fields are supported in this profile:
Authenticator Control
It is noted that the intended model of authentication of the
subject in a long term one, and the advice as offered in [RFC4211]
is that the Authenticator Control field be used.
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[Note - not for publication: The method of generation and
authentication of this field is to be specified. The desirable
properties include the ability to validate the subject and the
authenticity of the provided public key.]
Resource Class
The profile defines an additional control for Resource Certificate
Requests, namely a Resource Class control.
The Subject MUST specify a Resource Class value as specified by
the CA to which the request refers. The CA will issue a
certificate with the IPAddress and AS Number resources that match
the subject's right-of-use of these resources with the class of
resources specified by the Resource Class control value.
[Note - not for publication: This specification of the resource
class is related the various forms of resource allocation which
imply that an entity may be the holder of resources with differing
validation dates and differing validation paths, even when the
entity is the recipient of resources allocated from a single
'upstream' issuing registry. Due to this consideration it may not
be possible to issue a single certificate with an all-encompassing
resource set. Alternatively it is possible to define a structure
where there is no Resource Class specified and the issuer issues a
set of spanning certificates for all resources held by the subject
(i.e. all resources that fall under the subject's "right-of-use")]
6. Resource Certificate Validation
This section describes the Resource Certificate validation procedure.
This refines the generic procedure described in [RFC3280]:
To meet this goal, the path validation process verifies, among other
things, that a prospective certification path (a sequence of n
certificates) satisfies the following conditions:
1. for all x in {1, ..., n-1}, the subject of certificate x is the
issuer of certificate x+1;
2. certificate 1 is issued by a trust anchor;
3. certificate n is the certificate to be validated; and
4. for all x in {1, ..., n}, the certificate was valid at the time
in question.
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6.1. Trust Anchors for Resource Certificates
The trust model used in the resource certificate framework in the
context of validation of assertions of public number resources in
public-use contexts is a top-down delegated CA model that mirrors the
delegation of resources from a registry distribution point to the
entities that are the direct recipients of these resources. Within
the trust model these recipient entities may, in turn, operate a
registry and perform further allocations or assignments. This is a
strict hierarchy, in that any number resource and a corresponding
recipient entity has only one 'parent' issuing registry for that
number resource (i.e. there is always a unique parent entity for any
resource and corresponding entity), and that the issuing registry is
not a direct or indirect subordinate recipient entity of the
recipient entity in question (i.e. no loops in the hierarchy). The
only exception to the "no loop" condition are the nominated trust
anchors, where a self-signed certificate is issued.
At the time of preparing this draft there are proposed to be multiple
roots of this public number resource hierarchy, corresponding to
multiple trust anchors. These trust anchors are the self-signed
certificates that are issued by the Regional Internet Registries.
Each self-signed certificate issued by a RIR contains a resource set
that describes those resources where the RIR is administratively
responsible. There MUST NOT be overlap of resources in the IP
resource extensions across the collection of RIR self-signed
certificates. This implies that a validation path for any valid
certificate is unique, in the sense that the path will terminate with
a single trust anchor.
Cross-certification of these trust anchors, where one trust anchor
entity issues a certificate with a subject of another trust anchor is
not seen as providing any further substance to the integrity or ease
of validation in this trust model, so cross-certification is not used
in the trust anchor structure for this Resource Certificate
framework.
The adoption of a single trust anchor as a unique distinguished root
of this certificate hierarchy is a potential future option here, and
within the proposed framework some care has been taken not to
preclude the potential for a single distinguished root for this
certificate framework that could issue a certificate to each RIR with
a resource extension that matches the resource sets that fall under
the administrative responsibility of each RIR.
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6.2. Resource Extension Validation
The IP resource extension definition [RFC3779] defines a critical
extensions for Internet number resources. These are ASN.1 encoded
representations of the IPv4 and IPv6 address range (either as a
prefix/length, or start-end pair) and the AS number set.
Valid Resource Certificates MUST have a valid IP address and/or AS
number resource extension. In order to validate a Resource
Certificate the resource extension must also be validated. This
validation process relies on definitions of comparison of resource
sets:
more specific Given two IP address or AS number contiguous ranges, A
and B, A is "more specific" than B if range B includes all IP
addresses or AS numbers described by range A, and if range B is
larger than range A.
equal Given two IP address or AS number contiguous ranges, A and B,
A is "equal" to B if range A describes precisely the same
collection of IP addresses or AS numbers as described by range B.
The definition of "inheritance" in [RFC3779]is equivalent to this
"equality" comparison.
Validation of a certificate's resource extension in the context of an
ordered certification path of {1,2, ... , n} where '1'is a trust
anchor and 'n' is the target certificate, implies that each of the
contiguous resource sets of IP addresses and AS Numbers described in
certificate x, for 'x' is greater than , are more specific or equal
to the resources described in certificate x-1.
6.3. Resource Certificate Path Validation
Validation of signed resource data using a target resource
certificate consists of assembling an ordered sequence (or
'Certificate Path') of certificates ({1,2,...n} where '1' is a trust
anchor, and 'n' is the target certificate) verifying that all of the
following conditions hold:
1. The certificate can be verified using the Issuer's public key and
the signature algorithm
2. The current time lies within the certificate's Validity From and
To values.
3. The certificate contains all fields that MUST be present and
contains field values as specified in this profile for all field
values that MUST be present.
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4. No field value that MUST NOT be present is present in the
certificate.
5. The Issuer has not revoked the certificate by placing the
certificate's serial number on the Issuer's current Certificate
Revocation List, and the CRL is itself valid.
6. That the resource extension data is equal to or more specific
than the resource extension data contained in a valid certificate
where this Issuer is the Subject (the previous certificate in the
ordered sequence)
7. The Certificate Path originates at a trust anchor, and there
exists a signing chain across the Certificate Path where the
Subject of Certificate x in the Certificate Path matches the
Issuer in Certificate x+1 in the Certificate Path.
Validation of a certificate may perform these tests in any chosen
order.
A Resource Certificate may have a number of potential parent
certificates, where a potential parent certificate is one where the
subject name matches the issuer name of the resource certificate. A
candidate parent certificate is any member of the parent certificate
set where the resource extension validity constraint is satisfied,
and a valid candidate parent certificate is any candidate parent
certificate that also matches validity conditions 1 through 6. A
valid parent certificate is a valid candidate parent certificate that
also matches validity condition 7.
Certificates and CRLs used in this process may be found on a single
repository, maintained by a regular top-down walk from the Root Trust
Anchors via Issuer certificates and their SIA fields as forward
pointers, plus the CRLDP. Alternatively, validation may be performed
using a bottom-up process with on-line certificate access using the
AIA and CRLDP pointers to guide the certificate retrieval process.
There exists the possibility of encountering certificate paths that
are arbitrarily long, or attempting to generate paths with loops as
means of creating a potential DOS attack on a certificate validator.
Some further heuristics may be required to halt the validation
process in order to avoid some of the issues associated with attempts
to validate such structures. It is suggested that implementations of
Resource Certificate validation MAY halt with a validation failure if
the certificate path length exceeds a pre-determined configuration
parameter.
In the context of Resource Certificates that are generated in respect
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of public resources and with the framework of the associated resource
distribution process, it is suggested that this configuration
parameter of maximum certificate path length be set to a value of
100. (There is no particular reason for suggesting this value other
than the observation that it appears to be comfortably longer than
any real distribution chain for public number resources, without
being too long so as to pose potential DOS concerns for relying
parties performing a validation operation.)
7. Security Considerations
[to be completed]
8. IANA Considerations
[An OID for a resource class option in a certificate request may need
to be defined.]
9. Acknowledgements
The authors would like to acknowledge the valued contributions from
Stephen Kent, Robert Kisteleki, Randy Bush, Russ Housley, Ricardo
Patara and Rob Austein in the preparation and subsequent review of
this document.
10. Normative References
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
September 1981.
[RFC2050] Hubbard, K., Kosters, M., Conrad, D., Karrenberg, D., and
J. Postel, "INTERNET REGISTRY IP ALLOCATION GUIDELINES",
BCP 12, RFC 2050, November 1996.
[RFC3280] Housley, R., Polk, W., Ford, W., and D. Solo, "Internet
X.509 Public Key Infrastructure Certificate and
Certificate Revocation List (CRL) Profile", RFC 3280,
April 2002.
[RFC3779] Lynn, C., Kent, S., and K. Seo, "X.509 Extensions for IP
Addresses and AS Identifiers", RFC 3779, June 2004.
[RFC4055] Schaad, J., Kaliski, B., and R. Housley, "Additional
Algorithms and Identifiers for RSA Cryptography for use in
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the Internet X.509 Public Key Infrastructure Certificate
and Certificate Revocation List (CRL) Profile", RFC 4055,
June 2005.
[RFC4158] Cooper, M., Dzambasow, Y., Hesse, P., Joseph, S., and R.
Nicholas, "Internet X.509 Public Key Infrastructure:
Certification Path Building", RFC 4158, September 2005.
[RFC4211] Schaad, J., "Internet X.509 Public Key Infrastructure
Certificate Request Message Format (CRMF)", RFC 4211,
September 2005.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006.
Appendix A. Example Resource Certificate
The following is an example Resource Certificate.
Certificate Name: UDkyh1nUjIjk5_WpdkZMh3KuvYo-25f7.crt
Data:
Version: 3
Serial: 9719 (0x25f7)
Signature Algorithm:
Hash: SHA256, Encryption: RSA
Issuer: CN=APNIC-AP-IANA
Validity:
Not Before: Fri May 12 05:37:43 2006 GMT
Not After: Thu Aug 10 05:37:43 2006 GMT
Subject: CN=FC9B85ADDF5B
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
RSA Public Key: (1024 bit)
Modulus (1024 bit):
00:f2:e5:63:d6:e3:89:45:47:02:13:90:b7:e5:39:
a3:f0:8c:3b:27:0d:d1:90:92:46:9b:45:d0:52:34:
f1:7c:c7:34:9f:be:d0:41:18:ab:35:43:62:89:2e:
3e:32:ab:01:e2:86:76:2a:44:83:49:4c:83:02:b4:
0c:2a:b0:b2:82:c6:35:24:7b:16:7a:35:42:36:15:
18:50:fe:8b:7f:c9:04:18:69:6b:ed:59:0d:61:ea:
20:ef:cd:19:30:9f:ce:b8:4a:f5:fb:ad:81:42:ab:
57:72:0c:47:b0:d8:30:c0:0c:5b:52:dc:aa:94:95:
3e:fe:44:ac:d5:b0:f4:d5:cb
Exponent: 65537 (0x10001)
X509v3 extensions:
Basic Constraints:
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CA:TRUE
Subject Key Identifier:
keyid: 50:39:32:87:59:D4:8C:88:E4:E7:F5:A9:
76:46:4C:87:72:AE:BD:8A
Authority Key Identifier:
keyid: 19:54:CD:F2:81:C6:4E:31:09:6D:3A:15:
E6:88:39:30:21:A6:56:73
Key Usage: critical
Certificate Sign, CRL Sign
CRL Distribution Points:
URI:rsync://rsync.apnic.net/repository/
pvpjvwUeQix2e54X8fGbhmdYMo0/
GVTN8oHGTjEJbToV5og5MCGmVnM/
GVTN8oHGTjEJbToV5og5MCGmVnM.crl
Authority Information Access:
CA Issuers - URI:rsync://rsync.apnic.net/repository/
pvpjvwUeQix2e54X8fGbhmdYMo0/
GVTN8oHGTjEJbToV5og5MCGmVnM
Subject Information Access:
CA Repository - URI:rsync://rsync.apnic.net/repository/
pvpjvwUeQix2e54X8fGbhmdYMo0/
GVTN8oHGTjEJbToV5og5MCGmVnM/
UDkyh1nUjIjk5_WpdkZMh3KuvYo
Certificate Policies: critical
Policy: 1.3.6.1.5.5.7.14.2
ipAddrBlock: critical
192.0.0.0/24
autonomousSysNum: critical
64512
Subject Alternative Name:
DirName:/CN=<subject_supplied_string>
Signature:
72:27:9c:bc:a8:7f:c0:f0:27:62:a1:1f:55:b3:c7:b1:31:c9:fc:
42:84:71:30:3b:0d:c0:d6:ad:79:b1:f6:1d:14:e8:f3:0f:f3:dd:
40:3d:ae:28:a6:33:96:b6:d3:7d:d2:f3:ac:d3:8e:d4:2e:ad:ab:
71:4d:05:74:20:ed:bc:e3:bd:85:7f:af:8b:70:3e:b8:90:b6:2d:
a5:e3:9d:2a:c8:a9:9b:73:3c:03:43:d2:b8:d2:4e:68:34:eb:db:
3c:44:eb:eb:1e:3b:03:d9:3b:e0:64:a6:31:90:9b:2c:4a:26:8e:
0e:36:4c:ee:c8:e9:29:6b:78:61:87:05:e2:f9
Appendix B. Example Certificate Revocation List
The following is an example Certificate Revocation List.
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Certificate Name: GVTN8oHGTjEJbToV5og5MCGmVnM.crl
Data:
Version: 2
Issuer: CN=APNIC-AP-IANA
Effective Date: Fri May 12 05:37:43 2006 GMT
Next Update: Fri May 26 05:37:43 2006 GMT
Signature algorithn
Hash: SHA256, Encryption: RSA
CRL V2 Extensions:
Authority Key Identifier:
Keyid: 19:54:cd:f2:81:c6:4e:31:09:6d:3a:15:
e6:88:39:30:21:a6:56:73
Certificate Issuer:
CN=APNIC-AP-IANA
Certificate Serial Number: 1b
CRL Number: 1097
Revocation List:
Revoked Certificates
Serial Number: 0b
Revocation Date: Mon May 8 05:10:19 2006 GMT
Serial Number: 0c
Revocation Date: Mon May 8 05:10:19 2006 GMT
Authors' Addresses
Geoff Huston
Asia Pacific Network Information Centre
Email: gih@apnic.net
URI: http://www.apnic.net
Robert Loomans
Asia Pacific Network Information Centre
Email: robertl@apnic.net
URI: http://www.apnic.net
George Michaelson
Asia Pacific Network Information Centre
Email: ggm@apnic.net
URI: http://www.apnic.net
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Full Copyright Statement
Copyright (C) The Internet Society (2006).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
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ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
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