Internet Engineering Task Force (IETF) G. Huston

Internet Engineering Task Force (IETF) G. Huston
Request for Comments: 6492 R. Loomans
Category: Standards Track B. Ellacott
ISSN: 2070-1721 APNIC
R. Austein
ISC
February 2012

A Protocol for Provisioning Resource Certificates

Abstract

This document defines a framework for certificate management
interactions between an Internet Number Resource issuer ("issuer")
and an Internet Number Resource recipient ("subject") through the
specification of a protocol for interaction between the two parties.
The protocol supports the transmission of requests from the subject,
and corresponding responses from the issuer encompassing the actions
of certificate issuance, certificate revocation, and certificate
status information reports. This protocol is intended to be limited
to the application of Internet Number Resource Certificate management
and is not intended to be used as part of a more general certificate
management framework.

Status of This Memo

This is an Internet Standards Track document.

This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.

Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6492.

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RFC 6492 ResCert Provisioning February 2012

Copyright Notice

Copyright (c) 2012 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
(http://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 Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.

Table of Contents

1. Introduction ....................................................3
1.1. Terminology ................................................3
2. Scope ...........................................................4
3. Protocol Specification ..........................................4
3.1. CMS Profile ................................................5
3.1.1. SignedData Content Type .............................5
3.1.2. CMS Object Validation ..............................10
3.1.3. ASN.1 Specification of the CMS Signed Object .......12
3.2. Common Message Format .....................................14
3.3. Control - Resource Class Query ............................16
3.3.1. Resource Class List Query ..........................16
3.3.2. Resource Class List Response .......................17
3.4. CA - Certificate Issuance .................................21
3.4.1. Certificate Issuance Request .......................21
3.4.2. Certificate Issuance Response ......................24
3.5. Certificate Revocation ....................................24
3.5.1. Certificate Revocation Request .....................25
3.5.2. Certificate Revocation Response ....................26
3.6. Request-Not-Performed Response ............................26
3.7. XML Schema ................................................27
4. Security Considerations ........................................29
5. IANA Considerations ............................................30
5.1. application/rpki-updown ...................................30
6. Acknowledgements ...............................................30
7. References .....................................................31
7.1. Normative References ......................................31
7.2. Informative References ....................................32

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1. Introduction

This document defines a framework for certificate management
interactions between an Internet Number Resource issuer ("issuer")
and an Internet Number Resource recipient ("subject") through the
specification of a protocol for interaction between the two parties.
The protocol supports the transmission of requests from the subject,
and corresponding responses from the issuer encompassing the actions
of certificate issuance, certificate revocation, and certificate
status information reports. This protocol is intended to be limited
to the application of Internet Number Resource certificate management
and is not intended to be used as part of a more general certificate
management framework.

1.1. Terminology

Terms used in this document are:

"Internet Number Resource" (or "resource") used in the context of
this document to refer to Autonomous System (AS) numbers, IP
version 4 addresses, and IP version 6 addresses.

"issuer" used in the context of this document as an entity
undertaking the role of resource issuer. An "issuer" is a
Certification Authority (CA), and can issue resource certificates.

"subject" used in the context of this document as an entity
undertaking the role of resource recipient who is the subject of a
resource certificate. A "subject" may be issued with a CA-enabled
certificate, allowing the entity to also assume the role of an
"issuer".

"resource class" a resource class refers to a collection of
resources that can be certified in a single resource certificate
by an issuer.

"server" in the context of this client/server protocol
specification, the issuer assumes the role of the "server".

"client" in the context of this client/server protocol
specification, the subject assumes the role of the "client".

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].

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2. Scope

This Resource Public Key Infrastructure (RPKI) certificate
provisioning protocol defines a basic set of interactions that allow
a subject to request certificate issuance, revocation, and status
information from the issuer, and for an issuer to maintain an issued
certificate set that is aligned to the allocation records relating to
each subject. The issuer's resource allocation database is the
authoritative source of what resource allocations the issuer may
certify for a subject.

A resource recipient (subject) may also undertake the role of a
resource issuer (issuer).

This protocol specification does not encompass:

o signing of objects with keys that are certified by resource
certificates, nor the issuance of end-entity certificates.

o the specification of interaction with the issuer's resource
allocation database, nor the specification of a protocol to manage
the publication repository.

o the interactions between client and server that establish
identities, or the exchange of the certificates and validation
Public Key Infrastructure (PKI) contexts used in the Cryptographic
Message Syntax (CMS) [RFC5652] message exchange.

o the interactions between client and server that allow respective
local CMS signing time values to be reset to mutually recognized
values.

3. Protocol Specification

This RPKI certificate provisioning protocol is expressed as a simple
request/response interaction, where the client passes a request to
the server, and the server generates a corresponding response.

The protocol is implemented as an exchange of messages.

Messages are passed over an HTTP [RFC2616] end-to-end connection. A
message exchange commences with the client initiating an HTTP POST
with content type of "application/rpki-updown" and the message object
as the body. The server's response is similarly an HTTP response,
with the message object carried as the body of the response and with
a response content type of "application/rpki-updown". The content of
the POST and the server's response are "well-formed" CMS [RFC5652]
objects, encoded using the Distinguished Encoding Rules (DER) for

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ASN.1 [X.509-88], formatted in accordance with the CMS profile
specified in the following section. CMS is used as the signing
format to sign the message object. The CMS message includes an end-
entity (EE) certificate that is to be used to validate the CMS
digital signature (see Section 3.1.1.4); the certificate chain that
is used to validate the EE certificate MAY be included in the CMS
message, and if it is not present it is assumed to have been
communicated between the two entities, through mechanisms not defined
in this specification.

The protocol's request/response interaction is assumed to be
reliable, in that all requests MUST generate a matching response.
The protocol requires sequential operation for each distinct client,
where the server MUST NOT accept a client's request unless it has
generated and sent a response to the client's previous request.
Attempts by the client to initiate multiple requests in parallel
(i.e., multiple concurrent requests with a common sender attribute
(see Section 3.2) in the request) MUST be detected by the server and
rejected with an error response (i.e., an error code 1101 response).

3.1. CMS Profile

The format of the CMS object is:

ContentInfo ::= SEQUENCE {
contentType ContentType,
content [0] EXPLICIT ANY DEFINED BY contentType }

ContentType ::= OBJECT IDENTIFIER

The content-type is the signed-data type of id-data, namely
id-signedData, OID = 1.2.840.113549.1.7.2. [RFC5652]

3.1.1. SignedData Content Type

According to the CMS standard [RFC5652], signed-data content types
are the ASN.1 type SignedData:

SignedData ::= SEQUENCE {
version CMSVersion,
digestAlgorithms DigestAlgorithmIdentifiers,
encapContentInfo EncapsulatedContentInfo,
certificates [0] IMPLICIT CertificateSet OPTIONAL,
crls [1] IMPLICIT RevocationInfoChoices OPTIONAL,
signerInfos SignerInfos }

DigestAlgorithmIdentifiers ::= SET OF DigestAlgorithmIdentifier
SignerInfos ::= SET OF SignerInfo

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Additionally, the SignerInfos set MUST contain only a single
SignerInfo object.

3.1.1.1. version

The version is the syntax version number. It MUST be 3,
corresponding to the signerInfo structure having version number 3.

3.1.1.2. digestAlgorithms

The digestAlgorithms set contains the Object Identifiers (OID)s of
the digest algorithm(s) used in signing the encapsulated content.
This set MUST contain exactly one digest algorithm OID, and the OID
MUST be selected from those specified in [RFC6485].

3.1.1.3. encapContentInfo

encapContentInfo is the signed content, consisting of a content type
identifier and the content itself. The encapContentInfo represents
the payload of the RPKI certificate provisioning protocol.

EncapsulatedContentInfo ::= SEQUENCE {
eContentType ContentType,
eContent [0] EXPLICIT OCTET STRING OPTIONAL }

ContentType ::= OBJECT IDENTIFIER

3.1.1.3.1. eContentType

The eContentType for the RPKI Protocol Message object is defined as
id-ct-xml, and has the numerical value of 1.2.840.113549.1.9.16.1.28.

id-smime OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840)
rsadsi(113549) pkcs(1) pkcs9(9) 16 }

id-ct OBJECT IDENTIFIER ::= { id-smime 1 }

id-ct-xml OBJECT IDENTIFIER ::= { id-ct 28 }

3.1.1.3.2. eContent

The content of an RPKI XML Protocol Object consists of a single
protocol message, structured according to a defined XML schema, as
defined in subsequent sections of this document. The eContent field
of the CMS object is formally defined using ASN.1 as:

RPKIXMLProtocolObject ::= OCTET STRING -- XML encoded message

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3.1.1.4. certificates

This field MUST be present and MUST contain the single EE certificate
of the key pair whose private key value was used to sign the CMS.
This MUST NOT be an RPKI certificate, and SHOULD be a certificate
that is recognized to attest to the identity of the party that
created the CMS object.

This field MAY contain CA certificates that a relying party MAY use
to validate the EE certificate.

3.1.1.5. crls

This field MUST be present. The contents of the field are specified
in [RFC5652]. The current Certificate Revocation List (CRL) issued
by the same CA that issued the EE certificate of the key pair whose
private key value was used to sign the CMS MUST be present in this
field. This field MAY contain CRLs issued by other CAs covering CA
certificates included in the certificates field of the CMS object
(see Section 3.1.1.4). This field MUST NOT contain any other CRLs.

3.1.1.6. SignerInfo

SignerInfo is defined in CMS as:

SignerInfo ::= SEQUENCE {
version CMSVersion,
sid SignerIdentifier,
digestAlgorithm DigestAlgorithmIdentifier,
signedAttrs [0] IMPLICIT SignedAttributes OPTIONAL,
signatureAlgorithm SignatureAlgorithmIdentifier,
signature SignatureValue,
unsignedAttrs [1] IMPLICIT UnsignedAttributes OPTIONAL }

3.1.1.6.1. version

The version number MUST be 3, corresponding with the choice of
SubjectKeyIdentifier for the sid.

3.1.1.6.2. sid

The sid is defined as:

SignerIdentifier ::= CHOICE {
issuerAndSerialNumber IssuerAndSerialNumber,
subjectKeyIdentifier [0] SubjectKeyIdentifier }

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In this profile, the sid MUST be the SubjectKeyIdentifier that
appears in the EE certificate carried in the CMS certificates field.

3.1.1.6.3. digestAlgorithm

The digestAlgorithm MUST consist of the OID of a digest algorithm
that conforms to the RPKI Algorithms and Key Size Profile
specification [RFC6485].

3.1.1.6.4. signedAttrs

The signedAttrs field is defined as:

SignedAttributes ::= SET SIZE (1..MAX) OF Attribute

UnsignedAttributes ::= SET SIZE (1..MAX) OF Attribute

Attribute ::= SEQUENCE {
attrType OBJECT IDENTIFIER,
attrValues SET OF AttributeValue }

AttributeValue ::= ANY

The signedAttr element MUST be present and MUST include the content-
type and message-digest attributes [RFC5652]. If either the signing-
time [RFC5652] attribute or the binary-signing-time attribute
[RFC6019], or both attributes, are present, they MUST also be
included as the SignedAttributes. Other signed attributes MUST NOT
be included.

The signedAttr MUST include only a single instance of any particular
attribute. Additionally, even though the syntax allows for a SET OF
AttributeValue, in this profile, the attrValues MUST consist of only
a single AttributeValue.

3.1.1.6.4.1. Content-Type Attribute

The content-type attribute MUST be present. The attrType OID for the
content-type attribute is 1.2.840.113549.1.9.3.

id-contentType OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs9(9) 3 }

ContentType ::= OBJECT IDENTIFIER

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The attrValues for the content-type attribute MUST match the
eContentType in the EncapsulatedContentInfo. This OID value is
defined as id-ct-xml and has the numerical value of
1.2.840.113549.1.9.16.1.28.

3.1.1.6.4.2. Message-Digest Attribute

The message-digest attribute MUST be present. The attrType OID for
the message-digest attribute is 1.2.840.113549.1.9.4.

id-messageDigest OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs9(9) 4 }

MessageDigest ::= OCTET STRING

The attrValues for the message-digest attribute contains the output
of the digest algorithm applied to the content being signed, as
specified in Section 5.4 of [RFC5652].

3.1.1.6.4.3. Signing-Time Attribute

The signing-time attribute MAY be present. The attrType OID for the
signing-time attribute is 1.2.840.113549.1.9.5.

id-signingTime OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs9(9) 5 }

SigningTime ::= Time

Time ::= CHOICE {
utcTime UTCTime,
generalizedTime GeneralizedTime }

The signing-time attribute specifies the time, based on the local
system clock, when the digital signature was applied to the content.

Guidelines regarding the use of UTCTime and GeneralizedTime in the
signing-time attribute can be found in Section 11.3 of [RFC5652].

Either one of the signing-time attribute or the binary-signing-time
attribute, or both attributes, MUST be present. If both the signing-
time and binary-signing-time attributes are present, they MUST both
represent the same underlying time value.

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3.1.1.6.4.4. Binary-Signing-Time Attribute

The binary-signing-time attribute MAY be present. The attrType OID
for the binary-signing-time attribute is 1.2.840.113549.1.9.16.2.46.

id-aa-binarySigningTime OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
smime(16) aa(2) 46 }

BinarySigningTime ::= BinaryTime

BinaryTime ::= INTEGER (0..MAX)

The binary-signing-time attribute specifies the time, based on the
local system clock, when the digital signature was applied to the
content. The precise definition of the binary-signing-time attribute
can be found at [RFC6019].

Either one of the signing-time or the binary-signing-time attributes,
or both attributes, MUST be present. If both the signing-time and
binary-signing-time attributes are present, they MUST both represent
the same underlying time value.

3.1.1.6.5. signatureAlgorithm Attribute

The signatureAlgorithm MUST conform to the RPKI Algorithms and Key
Size Profile specification [RFC6485].

3.1.1.6.6. signature Attribute

The signature value is defined as:

SignatureValue ::= OCTET STRING

The signature characteristics are defined by the digest and signature
algorithms.

3.1.1.6.7. UnsignedAttributes Attribute

unsignedAttrs MUST be omitted.

3.1.2. CMS Object Validation

Before a recipient of a CMS signed object can use the content of the
object, the recipient MUST validate the signed object by verifying
that all of the following conditions hold. A recipient may perform
these checks in any order.

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1. The CMS object is well formed, such that the signed object syntax
complies with this specification. In particular, that each of
the following is true:

a. The content-type of the CMS object is SignedData (OID
1.2.840.113549.1.7.2)

b. The version of the SignedData object is 3.

c. The certificates field in the SignedData object is present
and contains one EE certificate, the SubjectKeyIdentifier
field of which matches the sid field of the SignerInfo
object.

d. The crls field in the SignedData object is present.

e. The version of the SignerInfo is 3.

f. The signedAttrs field in the SignerInfo object is present and
contains one each of the content-type attribute (OID
1.2.840.113549.1.9.3), the message-digest attribute (OID
1.2.840.113549.1.9.4), and either or both of a single
instance of the signing-time attribute (OID
1.2.840.113549.1.9.5) and the binary-signing-time attribute
(OID 1.2.840.113549.1.9.16.2.46), and no other attributes.

g. The eContentType in the EncapsulatedContentInfo is an OID
that matches the attrValue in the content-type attribute and
has the attrValue of id-ct-xml.

h. The unsignedAttrs field in the SignerInfo object is omitted.

i. If both the signing-time attribute and the binary-signing-
time attribute are present, then their values represent the
same time.

j. The digestAlgorithm in the SignedData and SignerInfo objects
conforms to the RPKI Algorithms and Key Size Profile
specification [RFC6485].

k. The signatureAlgorithm in the SignerInfo object conforms to
the RPKI Algorithms and Key Size Profile specification
[RFC6485].

l. The signed object is DER encoded.

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2. The public key of the EE certificate (contained within the CMS
signed-data object) can be used to successfully verify the
signature on the signed object.

3. The EE certificate (contained within the CMS signed-data object)
is a valid EE certificate. In particular, there exists a valid
certification path from a trust anchor selected by the recipient
to this EE certificate.

4. At the current time, the EE certificate is not revoked. This can
be determined by confirming that the CRL contained in the crls
field of the CMS signed data object is a current valid CRL,
issued by the same CA that issued the EE certificate, and the CRL
does not list the serial number of the EE certificate.

5. The time represented by the signing-time attribute or the binary-
signing-time attribute is greater than or equal to the time value
passed in previously valid CMS objects that were passed from the
same originator to this recipient. This signing time value MAY
lie within the Validity Time of the EE certificate, but the EE
certificate SHOULD NOT be considered invalid if this is not the
case when all other checks listed here are passed.

3.1.3. ASN.1 Specification of the CMS Signed Object

The following is the ASN.1 specification of the CMS signed object
used by the RPKI provisioning protocol.

ContentInfo ::= SEQUENCE {
contentType ContentType,
content [0] EXPLICIT ANY DEFINED BY contentType }

ContentType ::= OBJECT IDENTIFIER

id-smime OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840)
rsadsi(113549) pkcs(1) pkcs9(9) 16 }
id-ct OBJECT IDENTIFIER ::= { id-smime 1 }

id-ct-xml OBJECT IDENTIFIER ::= { id-ct 28 }

RPKIXMLProtocolObject ::= OCTET STRING -- XML encoded message

id-signedData OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs7(7) 2 }

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SignedData ::= SEQUENCE {
version CMSVersion,
digestAlgorithms DigestAlgorithmIdentifiers,
encapContentInfo EncapsulatedContentInfo,
certificates [0] IMPLICIT CertificateSet OPTIONAL,
crls [1] IMPLICIT RevocationInfoChoices OPTIONAL,
signerInfos SignerInfos }

DigestAlgorithmIdentifiers ::= SET OF DigestAlgorithmIdentifier

SignerInfos ::= SET OF SignerInfo

SignerInfo ::= SEQUENCE {
version CMSVersion,
sid SignerIdentifier,
digestAlgorithm DigestAlgorithmIdentifier,
signedAttrs [0] IMPLICIT SignedAttributes OPTIONAL,
signatureAlgorithm SignatureAlgorithmIdentifier,
signature SignatureValue,
unsignedAttrs [1] IMPLICIT UnsignedAttributes OPTIONAL }

SignerIdentifier ::= CHOICE {
issuerAndSerialNumber IssuerAndSerialNumber,
subjectKeyIdentifier [0] SubjectKeyIdentifier }

SignedAttributes ::= SET SIZE (1..MAX) OF Attribute

Attribute ::= SEQUENCE {
attrType OBJECT IDENTIFIER,
attrValues SET OF AttributeValue }

AttributeValue ::= ANY

SignatureValue ::= OCTET STRING

id-contentType OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs9(9) 3 }

ContentType ::= OBJECT IDENTIFIER

id-messageDigest OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs9(9) 4 }

MessageDigest ::= OCTET STRING

id-signingTime OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs9(9) 5 }

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SigningTime ::= Time

Time ::= CHOICE {
utcTime UTCTime,
generalizedTime GeneralizedTime }

id-aa-binarySigningTime OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
smime(16) aa(2) 46 }

BinarySigningTime ::= BinaryTime

BinaryTime ::= INTEGER (0..MAX)

3.2. Common Message Format

The XML template for all messages is informally described as follows
(the RELAX NG compact form schema that formally describes the
protocol message objects is contained in Section 3.7):

---------------------------------------------------------------

<?xml version="1.0" encoding="UTF-8"?>
<message xmlns="http://www.apnic.net/specs/rescerts/up-down/"

version="1"
sender="sender name"
recipient="recipient name"
type="message type">

[payload]

</message>

---------------------------------------------------------------

version:
the value of this attribute is the version of this protocol. This
document describes version 1.

sender:
the value of this attribute is the agreed name of the message
sender, as determined between the client and the server by prior
arrangement.

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recipient:
the value of this attribute is the agreed name of the message
recipient, as determined between the client and the server by
prior arrangement.

type:
the possible values of this attribute are "list", "list_response",
"issue", "issue_response", "revoke", "revoke_response", and
"error_response".

Conforming parsers MUST reject any document with a version number
they do not understand or with any elements or attributes they do not
understand. Servers must generate an error response when receiving
such a request. Clients should generate an error when receiving such
a response.

The encapsulated content of the CMS wrapping is an XML document. The
remainder of this protocol specification omits this CMS wrapper and
only discusses the XML document.

Messages are checked using the following tests:

1. Check that the CMS is well-formed (see test 1 of Section 3.1.2).

2. Check that the XML is well-formed.

3. Check that the XML sender and recipient attributes reference a
known client and this server's system respectively for a query,
and the previously addressed server and this client for a
response.

4. Verify the digital signature using the public key provided in the
certificate carried in the CMS wrapper (see test 2 of Section
3.1.2).

5. Validate the CMS-provided certificate using the PKI that has been
determined by prior arrangement between the client and server
(see test 3 of Section 3.1.2).

6. Check that the signing time of the CMS is equal to or greater
than the signing time provided in the most recent previous
message that this recipient has received from this sender (see
test 4 of Section 3.1.2).

7. Check that the value of the version number of the message is 1.

These checks SHOULD be applied in the order specified here.

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Any errors encountered while checking items 1 through 7 MUST cause a
server to generate an "HTTP 400 Bad Request" response to the HTTP
POST operation. An error in step 7 MUST cause the server to generate
a "Request-Not-Performed" error response. Any errors encountered in
these tests by a client SHOULD cause the client to generate an error.

A server MAY perform flow control on the rate of processed requests.
Requests not processed due to such a flow control constraint MAY
cause the server to generate an "HTTP 503 Service Unavailable"
response. An HTTP 503 response MAY include an HTTP Retry-After:
header as a hint to the client.

3.3. Control - Resource Class Query

This query is used for a client to query a server for a list of all
resources that have been allocated or assigned by the server to the
client. In addition, the server's response will contain a copy of
the current certificates issued by the server's CA where this client
is the certificate's subject.

3.3.1. Resource Class List Query

The value of the message "type" message attribute for this query is:

type="list"

---------------------------------------------------------------

Payload:

[No message payload is defined for this query]

---------------------------------------------------------------

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3.3.2. Resource Class List Response

The value of the message "type" element for this response is:

type="list_response"

---------------------------------------------------------------

Payload:

<class class_name="class name"
cert_url="url"
resource_set_as="as resource set"
resource_set_ipv4="ipv4 resource set"
resource_set_ipv6="ipv6 resource set"
resource_set_notafter="datetime"
suggested_sia_head="[directory uri]" >
<certificate cert_url="url"
req_resource_set_as="as resource set"
req_resource_set_ipv4="ipv4 resource set"
req_resource_set_ipv6="ipv6 resource set" >
[certificate]
</certificate>

...

(repeated for each current certificate where the client
is the certificate's subject)

<issuer>[issuer's certificate]</issuer>
</class>

...

(repeated for each of the issuer's resource class where the
client has been allocated resources)

---------------------------------------------------------------

Where the client has been allocated resources from multiple resource
classes, the response MUST contain multiple class elements that
correspond to the complete set of the issuer's resource classes where
the client holds allocated resources. Those issuer's resource
classes where the client holds no allocated resources MUST NOT be
included in the response.

Where the issuer has issued multiple certificates in a resource class
signed with different keys (as may occur during a staged issuer-key

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rollover), only the most recent certificate issued with the currently
"active" issuer's key is to be listed in the response.

Each "class" element describes a set of resources that are certified
within the scope of a single certificate, referring to a single
resource class with a common validation path.

class_name:
the value of this attribute is the issuer-assigned name of the
issuer's resource class.

cert_url:
in the context of a class element, the value of this attribute is
a pointer to the issuer's CA certificate (i.e., a reference to the
immediate superior certificate, being the CA-enabled certificate
where the issuer is the certificate's subject). Its value is a
comma-separated list of URIs, of which at least one MUST be an
rsync URI [RFC5781]. Any comma values within a URI MUST be
escaped ("%2C"). The ordering of the list may be interpreted by
the client as a relative preference for access methods as
expressed by the publisher of this certificate.

resource_set_as:
in the context of a class element, the value of this attribute is
the set of AS numbers and AS number ranges that the issuer has
allocated to the client within the scope of this resource class,
presented in ASCII as a comma-separated list. The list elements
are decimal integer values and ranges of decimal integers
specified by the lowest and highest values of the range with a
hyphen delimiter, using the canonical order as described in
[RFC3779], without leading zeros, and with no white space or
punctuation other than the comma and the hyphen range designator
(e.g., resource_set_as="123,456-789,123456"). If there are no AS
numbers in this resource class, then the empty AS set is
represented by a null string value ("") for this attribute.

resource_set_ipv4:
in the context of a class element, the value of this attribute is
the set of IPv4 addresses that the issuer has allocated to the
client within the scope of this resource class. The value is
presented in ASCII as a comma-separated list of elements. Each
element is either an address prefix using the notation of <dotted
quad>/mask length, or a range specified as the lowest and highest
values of the range in dotted quad notation with a hyphen
delimiter. The list is presented in canonical order, as described
in [RFC3779]. The dotted quad notation is without leading zeros,
and the list contains no white space or punctuation other than the
period, forward slash, hyphen, and comma (e.g.,

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resource_set_ipv4="192.0.2.0/26,192.0.2.66-192.0.2.76"). If there
are no IPv4 addresses in this resource class, the empty IPv4
address set is represented by a null string value ("") for this
attribute.

resource_set_ipv6:
in the context of a class element, the value of this attribute is
the set of IPv6 addresses that the issuer has allocated to the
client within the scope of this resource class. The value is
presented in ASCII as a comma-separated list of elements. Each
element is either an address prefix using the notation of <hex
nibble sequence>/mask length, or a range specified as lowest and
highest values of the range in hex nibble notation with a hyphen
delimiter. Trailing zero nibbles are truncated and represented by
'::'. The list is presented in canonical order, as described in
[RFC3779]. The hex nibble sequence notation is without leading
zeros, and the list contains no white space or punctuation other
than the colon, forward slash, hyphen, and comma, and conforms to
the canonical format of [RFC5952] (e.g.,
resource_set_ipv6="2001:db8::/48,2001:db8:2::-2001:db8:5::"). The
XML Schema data type is
"http://www.w3.org/TR/xmlschema-2/#hexBinary" and the value is
case insensitive, with the canonical form being lower case. If
there are no IPv6 addresses in this resource class, the empty IPv6
address set is represented by a null string value ("") for this
attribute.

resource_set_notafter:
The value of this attribute specifies the date/time that would be
set in the Validity notAfter field in any new certificate issued
for this particular client within the scope of this resource
class, should the client request a new certificate. The time
format used for the value of this attribute is specified as
defined in ISO 8601 [ISO.8601:2004], and MUST use UTC time
represented as YYYY-MM-DDThh:mm:ssZ (e.g., 2007-11-29T04:40:00Z).
If the client's certificate has a validity notAfter time that is
different from this time, then the client SHOULD request a new
certificate to be issued for this resource class.

suggested_sia_head: (OPTIONAL)
If this field is present, then its value is a directory URI that
indicates a repository publication point that the server has made
available to the client to use for the client's collection of
published products. This specification does not encompass the
protocols that the client may use with the operator of the
repository publication point in order to publish objects at this
publication point.

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[issuer's certificate]
value is the Base64 encoding of the DER-encoded issuer's CA
certificate (the CA-enabled certificate where the issuer is the
certificate's subject).

Each certificate element describes the most recently issued
current certificate where the certificate's subject refers to the
client for each active client key pair. A "current" certificate
is a non-expired, non-revoked certificate. If no current
certificate has been issued, then no certificate element is to be
included in the response.

cert_url:
in the context of a certificate element, this is a pointer to the
location where the certificate issuer has published this
certificate. This field is the issuer's suggestion for the
Authority Information Access (AIA) field for the subject to use in
subordinate certificates that are issued by the subject.
According to the Resource Certificate Profile [RFC6487], the AIA
field is a non-empty (contains a minimum of 1 element) list of
URI's, one of which MUST be an rsync URI [RFC5781]. The order of
URI's in the AIA field may be interpreted as the publisher's
relative preference for access methods for this certificate. The
cert_url conforms to this AIA specification. Its value is a
comma-separated list of URIs, one of which MUST be an rsync URI.
Any comma values within a URI MUST be escaped ("%2C").

req_resource_set_as:
the set of AS numbers that were specified in the corresponding
original certificate request that defined the maximal requested
span of the certified AS number set, following the syntax
described above. If this attribute was present in the certificate
request, then the attribute MUST be present in this response;
otherwise, it MUST NOT be present.

req_resource_set_ipv4:
the set of IPv4 addresses that were specified in the corresponding
original certificate request that defined the maximal requested
span of the certified IPv4 address set, following the syntax
described above. If this attribute was present in the certificate
request, then the attribute MUST be present in this response;
otherwise, it MUST NOT be present.

req_resource_set_ipv6:
the set of IPv6 addresses that were specified in the corresponding
original certificate request that defined the maximal requested
span of the certified IPv6 address set, following the syntax
described above. If this attribute was present in the certificate

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request, then the attribute MUST be present in this response;
otherwise, it MUST NOT be present.

[certificate]
value is the Base64 encoding of the DER-encoded certificate.

3.4. CA - Certificate Issuance

This query is used by the client to request the server's CA to issue
a resource certificate for the resources that have been allocated or
assigned to the client. If the request can be successfully
processed, then the server's response includes the issued
certificate.

3.4.1. Certificate Issuance Request

The value of the message "type" element for this request is:

type="issue"

---------------------------------------------------------------

Payload:

<request
class_name="class name"
req_resource_set_as="as resource set"
req_resource_set_ipv4="ipv4 resource set"
req_resource_set_ipv6="ipv6 resource set">
[Certificate request]
</request>

---------------------------------------------------------------

The client MUST use different key pairs for each distinct resource
class.

The req_resource_set attributes are optional in the request.

If none of the req_resource_set attributes are specified, then the
request signifies that the complete set of all resources that match
the client's current resource allocation is to be included in the
issued certificate.

If any of the req_resource_set attributes are specified in the
request, then any missing req_resource_set attributes are to be
interpreted as specifying the complete set of the corresponding

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resource type that match the client's current resource allocation are
to be included in the issued certificate.

If the value of any included req_resource_set attributes is the null
value (""), then this indicates that no resources of that resource
type are to be included in the issued certificate.

The requested resource set values are held as a local record by the
issuer against the resource class and the client's public key. Any
subsequent Certificate Issuance Requests that specify the same
resource class and the same client's public key will (re)set the
issuer's local record of the requested resource sets to the most
recently specified values.

class_name:
value is the server's identifier of a resource class.

req_resource_set_as: (OPTIONAL)
the set of AS numbers that define the maximal requested span of
the certified AS number set, formatted as per the resource_set_as
attribute of the resource class list response.

req_resource_set_ipv4: (OPTIONAL)
the set of IPv4 addresses that define the maximal requested span
of the certified IPv4 address set, formatted as per the
resource_set_ipv4 attribute of the resource class list response.

req_resource_set_ipv6: (OPTIONAL)
the set of IPv6 addresses that define the maximal requested span
of the certified IPv6 address set, formatted as per the
resource_set_ipv6 attribute of the resource class list response.

[Certificate request]
value is the certificate request. This is a Base64 encoded DER
version of a request formatted using PKCS#10 [RFC2986]. The
certificate request is signed using the private key part of the
key pair whose public part is the subject key value in the
certification request. The signing algorithm is specified in
[RFC6485]. (This signature component is intended to demonstrate
proof of possession of the private key.)

The response to this request is a Certificate Issuance Response if
the request can be processed online. If the request cannot be
undertaken immediately, then the server MUST respond with a "Request-
Not-Performed" message, using the appropriate error code:

o If the resource class is not defined by the server, then the
server MUST return error code 1201.

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o If the client holds no resources in a defined resource class, then
the server MUST return error code 1202 and not proceed with the
request.

o If the certificate request payload is badly formed, then the
server MUST return error code 1203.

o If the public key used in the certificate request implies that the
client is attempting to use identical key pairs for multiple
resource classes, then the server MUST respond with a 1204 error
code.

o If the certificate issuer uses an off-line process to undertake
certificate issuance, and the server cannot directly respond to
the certificate issuance request with an issued certificate, then
the certificate issuer MUST respond to the first instance of this
request with an error code 1104 to indicate that the request is
being processed asynchronously. Subsequent repetitions of this
request while the off-line actions are being undertaken SHOULD
cause a response with error code 1101. In this context, where
off-line processes are invoked for certificate issuance, if the
certificate issuer determines in processing the request that the
issued certificate would be identical in all respects to the most
recently issued certificate for this client, other than the
certificate's serial number, were the certificate to be issued,
the issuer may choose to respond with the most recently issued
certificate and not initiate an off-line certificate issuance
request.

Note that a client, when receiving a 1104 response to a certificate
issuance request, MAY periodically resubmit the request, in which
case the client MUST receive an error code 1101 response while the
request is being processed, and a Certificate Issuance Response when
the certificate issuance process has completed. In such
circumstances, a client SHOULD limit the frequency of such repeated
requests to no more than 1 request in each 24-hour interval.

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3.4.2. Certificate Issuance Response

The value of the message "type" element for this response is:

type="issue_response"

---------------------------------------------------------------

Payload:

<class class_name="class name"
cert_url="url"
resource_set_as="as resource set"
resource_set_ipv4="ipv4 resource set"
resource_set_ipv6="ipv6 resource set" >
<certificate cert_url="url"
req_resource_set_as="as resource set"
req_resource_set_ipv4="ipv4 resource set"
req_resource_set_ipv6="ipv6 resource set" >
[certificate]
</certificate>
<issuer>[issuer's certificate]</issuer>
</class>

---------------------------------------------------------------

If the certificate issuer determines that the issued certificate
would be identical in all respects to the most recently issued
certificate for this client, other than the certificate's serial
number, were the certificate to be issued, the issuer may choose to
respond with the most recently issued certificate and not issue a new
certificate for this request.

The definition of the attributes and syntax of the values is the same
as the resource class list response, but the response only references
the (single) named resource class, and the (single) certificate
issued against the client's public key as provided in the
corresponding certificate request.

3.5. Certificate Revocation

This request 'retires' a client's key pair by requesting that the
server's CA revoke all certificates for this client (i.e., where this
client is the subject) that contain the matching public key, within
the scope of a named resource class. Individual certificates cannot
be revoked within the scope of this protocol.

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3.5.1. Certificate Revocation Request

The value of the message "type" element for this request is:

type="revoke"

---------------------------------------------------------------

Payload:

<key class_name="class name"
ski="[encoded hash of the subject public key]" />

---------------------------------------------------------------

This command directs the server's CA to immediately mark all issued
valid certificates issued by this issuer within the named resource
class with this client's subject name and the provided SKI value to
be marked as revoked, causing the issued certificates to be withdrawn
from the publication repository and to be listed in the server's
subsequent CRLs within this resource class. The issuer MUST ensure
that all certificates to be revoked were issued with the requesting
client as the certificate's subject.

class_name:
value is the issuer-assigned name of the issuer's resource class.

ski:
value is the encoded hash of the client's public key that is to be
revoked. The algorithm for the encoding is to generate the
160-bit SHA-1 hash of the client's public key, as defined in
method (1) of Section 4.2.1.2 of [RFC5280], and encode this value
using the Base 64 encoding with URL and Filename Safe Alphabet, as
defined in Section 5 of [RFC4648].

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3.5.2. Certificate Revocation Response

The value of the message "type" element for this response is:

type="revoke_response"

---------------------------------------------------------------

Payload:

<key class_name="class name"
ski="[encoded hash of the subject public key]" />

---------------------------------------------------------------

class_name:
value is the issuer-assigned name of the server's resource class.

ski:
value is the encoded hash of the client's public key that is to be
revoked. The algorithm for the encoding is to generate the
160-bit SHA-1 hash of the client's public key, as defined in
method (1) of Section 4.2.1.2 of [RFC5280], and encode this value
using the Base 64 encoding with URL and Filename Safe Alphabet, as
defined in Section 5 of [RFC4648].

3.6. Request-Not-Performed Response

The value of the message "type" element for this response is:

type="error_response"

---------------------------------------------------------------

Payload:

<status>[Code]</status>
<description xml:lang="en-US">[Readable text]</description>

---------------------------------------------------------------

All states where an error response if to be generated, either due to
detected errors or inconsistencies in the content of the request or
server-side states that prevent the request being performed, generate
a Request-Not-Performed response.

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description:
value is a text field. This element MAY be present. It's value
has no defined meaning within the scope of this protocol, and
implementations may assume that some form of human-readable text
may be used here. If the HTTP request that triggered this error
response includes an Accept-Language header as defined in Section
14.4 of the HTTP/1.1 specification [RFC2616], then the server MAY
include a second description element using the highest ranked
preferred language of the client. The en-US description MUST
always be included if the element is present.

The error code set is:

Code Value Description
1101 already processing request
1102 version number error
1103 unrecognized request type
1104 request scheduled for processing
1201 request - no such resource class
1202 request - no resources allocated in resource class
1203 request - badly formed certificate request
1204 request - already used key in request
1301 revoke - no such resource class
1302 revoke - no such key
2001 Internal Server Error - Request not performed

3.7. XML Schema

The following is a RELAX NG compact form schema describing version 1
of this protocol.

Note: As discussed in [XML], "the namespace name, to serve its
intended purpose, SHOULD have the characteristics of uniqueness
and persistence. It is not a goal that it be directly usable for
retrieval of a schema (if any exists)".

default namespace = "http://www.apnic.net/specs/rescerts/up-down/"

grammar {
resource_set_as = xsd:string { maxLength="512000"
pattern="[\-,0-9]*" }
resource_set_ip4 = xsd:string { maxLength="512000"
pattern="[\-,/.0-9]*" }
resource_set_ip6 = xsd:string { maxLength="512000"
pattern="[\-,/:0-9a-fA-F]*" }

class_name = xsd:token { minLength="1" maxLength="1024" }
ski = xsd:token { minLength="27" maxLength="1024" }

Huston, et al. Standards Track [Page 27]

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label = xsd:token { minLength="1" maxLength="1024" }
cert_url = xsd:string { minLength="10" maxLength="4096" }
base64_binary = xsd:base64Binary { minLength="4"
maxLength="512000" }

start = element message {
attribute version { xsd:positiveInteger {
maxInclusive="1" } },
attribute sender { label },
attribute recipient { label },
payload
}

payload |= attribute type { "list" }, list_request
payload |= attribute type { "list_response"}, list_response
payload |= attribute type { "issue" }, issue_request
payload |= attribute type { "issue_response"}, issue_response
payload |= attribute type { "revoke" }, revoke_request
payload |= attribute type { "revoke_response"}, revoke_response
payload |= attribute type { "error_response"}, error_response

list_request = empty
list_response = class*

class = element class {
attribute class_name { class_name },
attribute cert_url { cert_url },
attribute resource_set_as { resource_set_as },
attribute resource_set_ipv4 { resource_set_ip4 },
attribute resource_set_ipv6 { resource_set_ip6 },
attribute resource_set_notafter { xsd:dateTime },
attribute suggested_sia_head { xsd:anyURI { maxLength="1024"
pattern="rsync://.+"} }?,
element certificate {
attribute cert_url { cert_url },
attribute req_resource_set_as { resource_set_as }?,
attribute req_resource_set_ipv4 { resource_set_ip4 }?,
attribute req_resource_set_ipv6 { resource_set_ip6 }?,
base64_binary
}*,
element issuer { base64_binary }
}

issue_request = element request {
attribute class_name { class_name },
attribute req_resource_set_as { resource_set_as }?,
attribute req_resource_set_ipv4 { resource_set_ip4 }?,
attribute req_resource_set_ipv6 { resource_set_ip6 }?,

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base64_binary
}
issue_response = class

revoke_request = revocation
revoke_response = revocation

revocation = element key {
attribute class_name { class_name },
attribute ski { ski }
}

error_response =
element status { xsd:positiveInteger { maxInclusive="9999" } },
element description { attribute xml:lang { xsd:language },
xsd:string { maxLength="1024" } }*
}

4. Security Considerations

This protocol supports the maintenance of resource certificates that
the issuer issues for a subject in certifying resources that have
been allocated or assigned by the issuer to the subject [RFC6480].
This protocol assumes that the issuer and subject are known to each
other and have exchanged credentials so as to support the mutual
recognition of the digital signatures used to sign the CMS messages.
The mechanisms used to perform the associated credential exchange are
not described in this specification.

The protocol is a minimal query/response protocol that imposes strict
serialization on each query/response transaction, reducing the
potential for the subject and the issuer to lose synchronization over
the issued certificate state.

Validation of protocol objects (Section 3.1.2) requires that the CMS
signing-time value be greater than or equal to the time value passed
in the previously valid protocol objects that were passed from the
same originator to the same recipient. If a party inadvertently
sends a valid message (protocol object) with a signing time in the
future, then subsequent messages from the party in the same
client/server context can use signing-time value consistent with this
validation constraint, such that the signing times contained in
subsequent messages are greater than or equal to the signing-time
value of the previous valid message. (Note that it is not a
normative requirement that the signing time be precisely aligned to a
time of day clock, thus permitting arbitrarily large clock skew
values in the context of this protocol message exchange.) If the
client and server wish to reset the signing time to a mutually agreed

Huston, et al. Standards Track [Page 29]

RFC 6492 ResCert Provisioning February 2012

value, then, (as noted in Section 2) the interactions between the
client and the server to achieve this outcome are not encompassed in
this protocol.

5. IANA Considerations

IANA has registered the following media type:

application/rpki-updown

5.1. application/rpki-updown

Type name: application
Subtype name: rpki-updown
Required parameters: None
Optional parameters: None
Encoding considerations: binary
Security considerations: Carries an RPKI Provisioning Protocol
Message, as defined in this document.
Interoperability considerations: None
Published specification: This document
Applications that use this media type: HTTP [RFC5652]
Additional information:
Magic number(s): None
File extension(s):
Macintosh File Type Code(s):
Person & email address to contact for further information:
Geoff Huston <[email protected]>
Intended usage: COMMON
Restrictions on usage: Only to be used as an RPKI Provisioning
Protocol message object type, as defined in this document.
Author: Geoff Huston <[email protected]>
Change controller: Geoff Huston <[email protected]>

6. Acknowledgements

The authors would like to acknowledge the valued contributions from
Russ Housley, Steve Kent, Randy Bush, George Michaelson, Robert
Kisteleki, Tim Bruijnzeels, and Carsten Bormann in the preparation of
the protocol described in this document.

Huston, et al. Standards Track [Page 30]

RFC 6492 ResCert Provisioning February 2012

7. References

7.1. Normative References

[ISO.8601:2004]
ISO, "ISO 8601:2004 Representation of dates and Times",
2004.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.

[RFC2986] Nystrom, M. and B. Kaliski, "PKCS #10: Certification
Request Syntax Specification Version 1.7", RFC 2986,
November 2000.

[RFC3779] Lynn, C., Kent, S., and K. Seo, "X.509 Extensions for IP
Addresses and AS Identifiers", RFC 3779, June 2004.

[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, October 2006.

[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, May 2008.

[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
RFC 5652, September 2009.

[RFC5781] Weiler, S., Ward, D., and R. Housley, "The rsync URI
Scheme", RFC 5781, February 2010.

[RFC5952] Kawamura, S. and M. Kawashima, "A Recommendation for IPv6
Address Text Representation", RFC 5952, August 2010.

[RFC6019] Housley, R., "BinaryTime: An Alternate Format for
Representing Date and Time in ASN.1", RFC 6019, September
2010.

[RFC6485] Huston, G., "The Profile for Algorithms and Key Sizes for
Use in the Resource Public Key Infrastructure (RPKI)", RFC
6485, February 2012.

Huston, et al. Standards Track [Page 31]

RFC 6492 ResCert Provisioning February 2012

[X.509-88] CCITT, "Recommendation X.509: The Directory-
Authentication Framework", 1988.

7.2. Informative References

[RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support
Secure Internet Routing", RFC 6480, February 2012.

[RFC6487] Huston, G., Michaelson, G., and R. Loomans, "A Profile for
X.509 PKIX Resource Certificates", RFC 6487, February
2012.

[XML] Bray, T., Hollander, D., Layman, A., Tobin, R., and H.
Thompson, "Namespaces in XML 1.0 (Third Edition)", World
Wide Web Consortium Recommendation REC-xml-names-20091208,
December 2009, <http://www.w3.org/TR/2009/REC-xml-
names-20091208/>.

Authors' Addresses

Geoff Huston
APNIC

EMail: [email protected]
URI: http://www.apnic.net

Robert Loomans
APNIC

EMail: [email protected]
URI: http://www.apnic.net

Byron Ellacott
APNIC

EMail: [email protected]
URI: http://www.apnic.net

Rob Austein
Internet Systems Consortium

EMail: [email protected]

Huston, et al. Standards Track [Page 32]