Internet DRAFT - draft-huston-sidr-rfc6490-bis
draft-huston-sidr-rfc6490-bis
SIDR G. Huston
Internet-Draft APNIC
Obsoletes: 6490 (if approved) S. Weiler
Intended status: Standards Track SPARTA, Inc.
Expires: August 15, 2014 G. Michaelson
APNIC
S. Kent
BBN
February 11, 2014
Resource Certificate PKI (RPKI) Trust Anchor Locator
draft-huston-sidr-rfc6490-bis-01
Abstract
This document defines a Trust Anchor Locator (TAL) for the Resource
Certificate Public Key Infrastructure (RPKI).
Status of this Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on August 15, 2014.
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Copyright (c) 2014 IETF Trust and the persons identified as the
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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. Trust Anchor Locator . . . . . . . . . . . . . . . . . . . . . 3
2.1. Trust Anchor Locator Format . . . . . . . . . . . . . . . . 3
2.2. TAL and Trust Anchor Certificate Considerations . . . . . . 4
2.3. Example . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Relying Party Use . . . . . . . . . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
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1. Introduction
This document defines a Trust Anchor Locator (TAL) for the Resource
Certificate Public Key Infrastructure (RPKI) [RFC6480]. This format
may be used to distribute trust anchor material using a mix of out-
of-band and online means. Procedures used by Relying Parties (RPs)
to verify RPKI signed objects SHOULD support this format to
facilitate interoperability between creators of trust anchor material
and RPs.
1.1. Terminology
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].
2. Trust Anchor Locator
2.1. Trust Anchor Locator Format
This document does not propose a new format for trust anchor
material. A trust anchor in the RPKI is represented by a self-signed
X.509 Certificate Authority (CA), a format commonly used in PKIs and
widely supported by RP software. This document specifies a format
for data used to retrieve and verify the authenticity of a trust
anchor in a very simple fashion. That data is referred to as the
TAL.
The motivation for defining the TAL is to enable selected data in the
trust anchor to change, without needing to effect re-distribution of
the trust anchor per se. In the RPKI, certificates contain
extensions that represent Internet Number Resources (INRs) [RFC3779].
The set of INRs associated with an entity acting as a trust anchor is
likely to change over time. Thus, if one were to use the common PKI
convention of distributing a trust anchor to RPs in a secure fashion,
this procedure would need to be repeated whenever the INR set for the
entity acting as a trust anchor changed. By distributing the TAL (in
a secure fashion), instead of the trust anchor, this problem is
avoided, i.e., the TAL is constant so long as the TA's public key and
its location does not change.
The TAL is analogous to the TrustAnchorInfo data structure [RFC5914]
adopted as a PKIX standard. That standard could be used to represent
the TAL, if one defined an rsync URI extension for that data
structure. However, the TAL format was adopted by RPKI implementors
prior to the PKIX trust anchor work, and the RPKI implementer
community has elected to utilize the TAL format, rather than define
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the requisite extension. The community also prefers the simplicity
of the ASCII encoding of the TAL, vs. the binary (ASN.1) encoding for
TrustAnchorInfo.
The TAL is an ordered sequence of:
1) a URI section, and
2) a subjectPublicKeyInfo [RFC5280] in DER format [X.509],
encoded in Base64 (see Section 4 of [RFC4648].
where the URI section is comprised of one of more of the ordered
sequence of:
1.1) An rsync URI [RFC5781] ,and
1.2) A <CRLF> or <LF> line break.
2.2. TAL and Trust Anchor Certificate Considerations
Each rsync URI in the TAL MUST reference a single object. It MUST
NOT reference a directory or any other form of collection of objects.
The referenced object MUST be a self-signed CA certificate that
conforms to the RPKI certificate profile [RFC6487]. This certificate
is the trust anchor in certification path discovery [RFC4158] and
validation [RFC5280][RFC3779].
The validity interval of this trust anchor SHOULD reflect the
anticipated period of stability the particular set of Internet Number
Resources (INRs) that are associated with the putative TA.
The INR extension(s) of this trust anchor MUST contain a non-empty
set of number resources. It MUST NOT use the "inherit" form of the
INR extension(s). The INR set described in this certificate is the
set of number resources for which the issuing entity is offering
itself as a putative trust anchor in the RPKI [RFC6480].
The public key used to verify the trust anchor MUST be the same as
the subjectPublicKeyInfo in the CA certificate and in the TAL.
The trust anchor MUST contain a stable key. This key MUST NOT change
when the certificate is reissued due to changes in the INR
extension(s), when the certificate is renewed prior to expiration or
for any reason other than a key change.
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Because the public key in the TAL and the trust anchor MUST be
stable, this motivates operation of that CA in an off-line mode.
Thus the entity that issues the trust anchor SHOULD issue a
subordinate CA certificate that contains the same INRs (via the use
of the "inherit" option in the INR extensions of the subordinate
certificate). This allows the entity that issues the trust anchor to
keep the corresponding private key of this certificate off-line,
while issuing all relevant child certificates under the immediate
subordinate CA. This measure also allows the CRL issued by that
entity to be used to revoke the subordinate (CA) certificate in the
event of suspected key compromise of this potentially more vulnerable
online operational key pair.
The trust anchor MUST be published at a stable URI. When the trust
anchor is re-issued for any reason, the replacement CA certificate
MUST be accessible using the same URI.
Becuase the trust anchor is a self-signed certificate, there is no
corresponding Certificate Revocation List that can be used to revoke
it, nor is there a manifest [RFC6486] that lists this certificate.
If an entity wishes to withdraw a self-signed CA certificate as a
putative Trust Anchor, for any reason, including key rollover, the
entity MUST remove the object from the location referenced in the
TAL.
Where the TAL contains two or more rsync URIs, then the same self-
signed CA certificate MUST be found at each referenced location. In
order to operational increase resilience, it is RECOMMENDED that the
domain name parts of each of these URIs resolve to distinct IP
addresses that are used by a diverse set of repository publication
points, and these IP addresses be included in distinct Route
Origination Authorizations (ROAs) objects signed by different CAs.
2.3. Example
rsync://rpki.example.org/rpki/hedgehog/root.cer
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAovWQL2lh6knDx
GUG5hbtCXvvh4AOzjhDkSHlj22gn/1oiM9IeDATIwP44vhQ6L/xvuk7W6
Kfa5ygmqQ+xOZOwTWPcrUbqaQyPNxokuivzyvqVZVDecOEqs78q58mSp9
nbtxmLRW7B67SJCBSzfa5XpVyXYEgYAjkk3fpmefU+AcxtxvvHB5OVPIa
BfPcs80ICMgHQX+fphvute9XLxjfJKJWkhZqZ0v7pZm2uhkcPx1PMGcrG
ee0WSDC3fr3erLueagpiLsFjwwpX6F+Ms8vqz45H+DKmYKvPSstZjCCq9
aJ0qANT9OtnfSDOS+aLRPjZryCNyvvBHxZXqj5YCGKtwIDAQAB
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3. Relying Party Use
In order to use the TAL to retrieve and validate a (putative) TA, an
RP SHOULD:
1. Retrieve the object referenced by (one of) the URI(s) contained
in the TAL.
2. Confirm that the retrieved object is a current, self-signed RPKI
CA certificate that conforms to the profile as specified in
[RFC6487].
3. Confirm that the public key in the TAL matches the public key in
the retrieved object.
4. Perform other checks, as deemed appropriate (locally), to ensure
that the RP is willing to accept the entity publishing this self-
signed CA certificate to be a trust anchor, relating to the
validity of attestations made in the context of the RPKI
(relating to all resources described in the INR extension of this
certificate).
An RP SHOULD perform these functions for each instance of TAL that it
is holding for this purpose every time the RP performs a re-
synchronization across the local repository cache. In any case, an
RP also SHOULD perform these functions prior to the expiration of the
locally cached copy of the retrieved trust anchor referenced by the
TAL.
In the case where a TAL contains multiple URIs, RP may use a locally
defined preference rule to select the URI from where fetch the Trust
Anchor certificate. Some examples are:
o Using the order provided in the TAL
o Selecting the URI randomly from the available list
o Creating a prioritized list of URIs based on RP specific
parameters, such as connection establishment delay
If the connection to the preferred URI fails, or the fetched CA
certificate public key does not match the TAL public key, the RP
SHOULD fetch the CA certificate from the next URI, according to the
local preference ranking.
4. Security Considerations
Compromise of a trust anchor private key permits unauthorized parties
to masquerade as a trust anchor, with potentially severe
consequences. Reliance on an inappropriate or incorrect trust anchor
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has similar potentially severe consequences.
This trust anchor locator does not directly provide a list of
resources covered by the referenced self-signed CA certificate.
Instead, the RP is referred to thetrust anchor itself and the INR
extension(s) within this certificate. This provides necessary
operational flexibility, but it also allows the certificate issuer to
claim to be authoritative for any resource. Relying parties should
either have great confidence in the issuers of such certificates that
they are configuring as trust anchors, or they should issue their own
self-signed certificate as a trust anchor and, in doing so, impose
constraints on the subordinate certificates.
5. IANA Considerations
[This document specifies no IANA actions.]
6. Acknowledgments
This approach to TA material was originally described by Robert
Kisteleki.
The authors acknowledge the contributions of Rob Austein and Randy
Bush, who assisted with earlier versions of this document and with
helpful review comments.
The authors acknowledge with work of Roque Gagliano, Terry Manderson
and Carloa Martinez Cagnazzo in developing the ideas behind the
inclusion of multiple URIs in the TAL.
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[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
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Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, May 2008.
[RFC5781] Weiler, S., Ward, D., and R. Housley, "The rsync URI
Scheme", RFC 5781, February 2010.
[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.
[X.509] ITU-T, "Recommendation X.509: The Directory -
Authentication Framework", 2000.
7.2. Informative References
[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.
[RFC5914] Housley, R., Ashmore, S., and C. Wallace, "Trust Anchor
Format", RFC 5914, June 2010.
[RFC6486] Austein, R., Huston, G., Kent, S., and M. Lepinski,
"Manifests for the Resource Public Key Infrastructure
(RPKI)", RFC 6486, February 2012.
Authors' Addresses
Geoff Huston
APNIC
Email: gih@apnic.net
URI: http://www.apnic.net
Samuel Weiler
SPARTA, Inc.
7110 Samuel Morse Drive
Colombia, Maryland 21046
USA
Email: weiler@sparta.com
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George Michaelson
Asia Pacific Network Information Centre
Email: ggm@apnic.net
URI: http://www.apnic.net
Stephen Kent
BBN Technologies
10 Moulton St.
Cambridge, MA 02138
USA
Email: kent@bbn.com
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