SIDR G. Huston
Internet-Draft G. Michaelson
Intended status: BCP APNIC
Expires: April 4, 2011 S. Kent
BBN
October 1, 2010
CA Key Rollover in the RPKI
draft-ietf-sidr-keyroll-01.txt
Abstract
This document describes an algorithm to allow an entity who
undertakes the role of a Certification Authority in the Resource
Public Key Infrastructure to perform a rollover of its key pair.
This document also notes the requirements placed on Relying Parties
who maintain a local cache of the objects that have been published in
the distributed Resource Public Key Infrastructure repository
publication structure.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 4, 2011.
Copyright Notice
Copyright (c) 2010 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
Huston, et al. Expires April 4, 2011 [Page 1]
Internet-Draft Key Rollover October 2010
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 and Concepts . . . . . . . . . . . . . . . . . 3
2. CA Key Rollover Procedure . . . . . . . . . . . . . . . . . . . 3
3. Relying Party Requirements . . . . . . . . . . . . . . . . . . 7
4. Reissuing Certificates and RPKI Signed Objects . . . . . . . . 7
4.1. CA Certificates . . . . . . . . . . . . . . . . . . . . . . 7
4.2. RPKI Signed Objects . . . . . . . . . . . . . . . . . . . . 7
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 8
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
8.1. Normative References . . . . . . . . . . . . . . . . . . . 8
8.2. Informative References . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
Huston, et al. Expires April 4, 2011 [Page 2]
Internet-Draft Key Rollover October 2010
1. Introduction
This document describes an algorithm to by employed by a
Certification Authority (CA) in the Resource Public Key
Infrastructure (RPKI) [ID.ietf-sidr-arch] to perform a rollover of
its key pair.
This document defines a conservative procedure for such entities to
follow when performing a key rollover, so that Relying Parties are in
a position to be able to validate all authentic objects in the RPKI
using the validation procedure described in [ID.ietf-sidr-arch] at
all times.
1.1. Terminology and Concepts
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" [RFC5280], "X.509
Extensions for IP Addresses and AS Identifiers" [RFC3779], the
profile for RPKI Certificates [ID.ietf-sidr-res-certs], and the RPKI
repository structure [ID.ietf-sidr-repos-struct] .
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 RFC 2119.
2. CA Key Rollover Procedure
A certification Authority (CA) in the RPKI is an entity that issues
certificates and CRLs. Over time, there will be many instances of a
CA. A CA instance is associated with a single key pair
([ID.ietf-sidr-res-certs]). The implication in the context of key
rollover is that, strictly speaking, a CA does not perform a key
rollover per se. In order to perform the equivalent of a key
rollover, the CA creates a new instance of itself, with a new key
pair, and then substitutes this new CA instance into the RPKI
hierarchy in place of the old CA instance.
There are several considerations regarding this procedure that MUST
be followed by a CA performing a key rollover operation. The
critical consideration is that the RPKI has potential application in
the area of control of routing integrity [ID.ietf-sidr-arch], , and
key rollover should not cause any transient hiatus where a Relying
Party (RP) is led to incorrect conclusions regarding the authenticity
of attestations made in the context of the RPKI. A CA cannot assume
that all RPs will perform path validation and path discovery in the
same fashion, and therefore the key rollover procedure MUST preserve
Huston, et al. Expires April 4, 2011 [Page 3]
Internet-Draft Key Rollover October 2010
the integrity of the CRLDP, SIA and AIA pointers in RPKI
certificates.
In the procedure described here, the CA creates a new CA instance,
and has the associated new public key published in the form of a new
CA certificate. While the current and new CA instances share a
single repository publication point, each CA has its own CRL and its
own manifest. Initially, the new CA publishes an empty CRL and a
manifest that contains a single entry for the CRL. The "current" CA
also maintains its published CRL and manifest at this Repository
publication point.
The CA performing key rollover waits for a period of time to afford
every RP an opportunity to discover and retrieve this new CA
certificate, and store it in its local RPKI Repository cache
instance. This period of time is termed the "staging period".
During this period, the CA will have a new CA instance, with no
subordinate products, and a current CA instance that has issued all
subordinate products. At the expiration of the staging period the
new CA instance MUST replace all (valid) subordinate products of the
current CA instance, overwriting the current subordinate products in
the CA's repository publication point. When this process is complete
the current CA instance is retired, and the new CA instance becomes
the current CA.
During the transition of the current and new CA instances it is
necessary for the new CA instance to re-issue all subordinate
products of the current CA. The procedure described here requires
that, with the exception of manifests and CRLs, the re-issued
subordinate products be published using the same repository
publication point object names, effectively overwriting the old
objects with these re-issued objects. The intent of this overwriting
operation is to ensure that the AIA pointers of subordinate products
at lower tiers in the RPKI hierarchy remain correct, and that CA key
rollover does not require any associated actions by any subordinate
CA.
There are three CA states described here:
CURRENT:
The CURRENT CA is the active CA instance used to accept and
process certificate issuance and revocation requests The starting
point for this algorithm is that the key of the CURRENT CA is to
be rolled over.
Huston, et al. Expires April 4, 2011 [Page 4]
Internet-Draft Key Rollover October 2010
NEW:
The NEW CA is the CA instance that is being created. The NEW CA
is not active, and thus does not accept nor process certificate
issuance and revocation requests. The NEW CA SHOULD issue a CRL
and an EE certificate in association with its manifest to provide
a trivial, complete, consistent instance of a CA.
OLD:
The CA instance is in the process of being removed. An OLD CA
instance is unable to process any certificate issuance and
revocation requests. An OLD CA instance will continue to issue
regularly scheduled CRLs and issue an EE certificate as part of
the process of updating its manifest to reflect the updated CRL.
To perform a key rollover operation the CA MUST perform the following
steps in the order given here. Unless specified otherwise each step
SHOULD be performed without any intervening delay. The process MUST
be run through to completion.
1. Generate a new key pair for use by the NEW CA. Because the
goal of this algorithm is key rollover, the key pair generated
in this step MUST be different from the pair in use by the
CURRENT CA.
2. Generate a certificate request with this key pair and pass the
request to the CA that issued the CURRENT CA certificate.
This request MUST include the same SIA extension that is
present in the CURRENT CA certificate. This request, when
satisfied, will result in the publication of the NEW CA
certificate. This (NEW) CA certificate will contain an
Subject Name selected by the issuer, which MUST be distinct
from the Subject Name used in the CURRENT CA certificate. The
CPS for the issuer of the NEW CA certificate will indicate the
time frame within which a certificate request is expected to
be processed.
3. Publish the NEW CA's CRL and manifest.
The steps involved here are:
- Wait for the issuer of the NEW CA to publish the NEW CA
certificate.
- As quickly as possible following the publication of the
NEW CA certificate, use the key pair associated with the
NEW CA to generate an initial, empty CRL, and publish
this CRL in the NEW CA's repository publication point.
Huston, et al. Expires April 4, 2011 [Page 5]
Internet-Draft Key Rollover October 2010
It is RECOMMENDED that the CRL for the NEW CA have a
nextUpdate value that will cause the CRL to be replaced
at the end of the Staging Period (see in Step 4 below).
- Generate a new key pair, and generate an associated EE
certificate request with an AIA value of the NEW CA's
repository publication point. Pass this EE certificate
request to the NEW CA, and use the returned (single-use)
EE certificate as the NEW CA's manifest EE certificate.
- Generate a manifest containing the new CA's CRL as the
only entry, and sign it with the private key associated
with the manifest EE certificate. Publish the manifest
at the NEW CA's repository publication point.
- Destroy the private key associated with the manifest EE
certificate.
4. The NEW CA enters a Staging Period. This duration of the
Staging Period is determined by the CA, but it MUST be no less
than 24 hours. The Staging Period is intended to afford an
opportunity for all RPs to download the NEW CA certificate,
prior to publication of certificates, CRLs, and RPKI signed
objects under the NEW CA. During the Staging Period, the NEW
CA SHOULD reissue, but not publish, all of the products that
were issued under the CURRENT CA. This includes all CA
certificates, EE certificates, and RPKI signed objects.
Section 4 describes how each reissued product relates to the
product that it replaces. During the Staging Period, the
CURRENT CA SHOULD continue to accept and process certificate
issuance requests and MUST continue to accept and process
certificate revocation requests. If any certificates are
issued by the CURRENT CA during the staging period, they MUST
be re-issued under the NEW CA during the period. Any
certificates that are revoked under the CURRENT CA MUST NOT be
re-issued under the NEW CA.
5. Upon expiration of the Staging Period, the NEW CA MUST publish
the signed products that have been re-issued under the NEW CA,
replacing the corresponding products issued under the CURRENT
CA at the NEW CA's repository publication point. This
replacement is implied by the file naming requirements imposed
by [ID.ietf-sidr-repos-struct] for these signed products. The
trivial manifest for the NEW CA (which contained only one
entry, for the NEW CA's CRL) is replaced by a manifest listing
all of these reissued, signed products. At this point the
CURENT CA becomes the OLD CA, and the NEW CA becomes the
CURRENT CA. Use the OLD CA to issue a manifest that lists
Huston, et al. Expires April 4, 2011 [Page 6]
Internet-Draft Key Rollover October 2010
only the OLD CA's CRL. It is anticipated that this step is
very brief, perhaps a few minutes in duration, because the CA
has reissued all of the signed products during the Staging
Period. Nonetheless, it is desirable that the activities
performed in this step be viewed as atomic by RPs.
6. Generate a certificate revocation request for the OLD CA
certificate and submit it to the issuer of that certificate.
When the OLD CA certificate is revoked, the CRL for the OLD CA
is removed from the repository, along with the manifest for
the OLD CA. The private key for the OLD CA is destroyed.
3. Relying Party Requirements
This procedure defines a Staging Period for CAs performing a key
rollover operation. This period is defined as a period no shorter
than 24 hours.
RPs who maintain a local cache of the distributed RPKI repository
MUST perform a local cache synchronisation operation against the
distributed RPKI repository at regular intervals of no longer than 24
hours.
4. Reissuing Certificates and RPKI Signed Objects
This section provides rules a CA MUST use when it reissues
certificates and RPKI signed objects as part of the key rollover
process. Note that CRLs and manifests are not reissued, per se.
They are generated for each CA instance. A manifest catalogues the
contents of a publication point relative to a CA instance. A CRL
lists revoked certificates, relative to a CA instance. Key rollover
processing for CRLs and manifests is described above, in Section 3.
4.1. CA Certificates
When a CA, as part of the key rollover process, reissues a CA
certificate, it copies all of the field and extension values from the
old certificate into the new certificate. The only exceptions to
this rule is that the certificate serial number MUST change, and the
notBefore value MAY be set to the current date and time.
4.2. RPKI Signed Objects
An RPKI signed object is a CMS signed-data object, containing an EE
certificate and a payload (content). When a key rollover occurs, the
Huston, et al. Expires April 4, 2011 [Page 7]
Internet-Draft Key Rollover October 2010
EE certificate for the RPKI signed object MUST be reissued, under the
key of the NEW CA. A CA may choose to treat this EE certificate the
same way that it deals with CA certificates, i.e., to copy over all
fields and extensions, and change only the serial number and the
notBefore date. If the CA adopts this approach, then the new EE
certificate is inserted into the CMS wrapper, but the signed context
remains the same. (If the signing time or binary signing time values
in the CMS wrapper are non-null, they MAY be updated to reflect the
current time.) Alternatively, the CA MAY elect to generate a new key
pair for this EE certificate. If it does so, the object content MUST
be resigned under the private key corresponding to the EE
certificate. In this case the EE certificate MUST contain a new
public key and a new notBefore value, it MAY contain a new notAfter
value, but all other field and extension values remain constant. (If
the signing time or binary signing time values in the CMS wrapper are
non-null, they MAY be updated to reflect the current time.)
5. Security Considerations
[To be added]
6. IANA Considerations
[Note to IANA, to be removed prior to publication: there are no IANA
considerations stated in this document.]
7. Acknowledgements
The authors would like to acknowledge the review comments of Tim
Bruijnzeels in preparing this document.
8. References
8.1. Normative References
[RFC3779] Lynn, C., Kent, S., and K. Seo, "X.509 Extensions for IP
Addresses and AS Identifiers", RFC 3779, June 2004.
[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.
Huston, et al. Expires April 4, 2011 [Page 8]
Internet-Draft Key Rollover October 2010
8.2. Informative References
[ID.ietf-sidr-arch]
Lepinski, M. and S. Kent, "An Infrastructure to Support
Secure Internet Routing", draft-ietf-sidr-arch-11 (work in
progress), September 2010.
[ID.ietf-sidr-repos-struct]
Huston, G., Loomans, R., and G. Michaleson, "A Profile for
Resource Certificate Repository Structure", Internet
Draft draft-ietf-sidr-repos-struct-04.txt, May 2010.
[ID.ietf-sidr-res-certs]
Huston, G., Michaleson, G., and R. Loomans, "A Profile for
X.509 PKIX Resource Certificates", Internet
Draft draft-ietf-sidr-res-certs-18.txt, May 2010.
Authors' Addresses
Geoff Huston
Asia Pacific Network Information Centre
Email: gih@apnic.net
URI: http://www.apnic.net
George Michaelson
Email: ggm@apnic.net
URI: http://www.apnic.net
Stephen Kent
BBN Technologies
10 Moulton St.
Cambridge, MA 02138
USA
Email: kent@bbn.com
Huston, et al. Expires April 4, 2011 [Page 9]
