Secure Inter-Domain Routing (sidr) Kent, S.
Internet Draft Kong, D.
Expires: August 2007 BBN Technologies
Intended Status: Proposed Standard February 2007
A Profile for Route Origin Authorizations (ROA)
draft-ietf-sidr-roa-format-00.txt
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Abstract
This document defines a standard profile for Route Origin
Authorizations (ROAs). A ROA is a digitally signed object that
provides a means of verifying that an IP address block holder has
authorized an Autonomous System (AS) to originate routes to that
address block.
Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
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document are to be interpreted as described in RFC-2119 Error!
Reference source not found..
Table of Contents
1. Introduction...................................................2
2. Basic Format...................................................3
2.1. Signed-Data Content Type..................................3
2.1.1. version..............................................3
2.1.2. digestAlgorithms.....................................3
2.1.3. encapContentInfo.....................................3
2.1.3.1. eContentType....................................4
2.1.3.2. eContent........................................4
2.1.4. certificates.........................................5
2.1.5. crls.................................................5
2.1.6. signerInfos..........................................5
2.1.6.1. version.........................................5
2.1.6.2. sid.............................................5
2.1.6.3. digestAlgorithm.................................6
2.1.6.4. signedAttrs.....................................6
2.1.6.5. signatureAlgorithm..............................6
2.1.6.6. signature.......................................6
2.1.6.7. unsignedAttrs...................................6
3. Security Considerations........................................6
4. IANA Considerations............................................7
5. Acknowledgments................................................7
6. References.....................................................8
6.1. Normative References......................................8
6.2. Informative References....................................8
Author's Addresses................................................9
Intellectual Property Statement..................................10
Disclaimer of Validity...........................................10
Copyright Statement..............................................10
1. Introduction
The primary purpose of the Internet IP Address and AS Number public
key infrastructure (PKI) system is to improve routing security. As
part of this system, a mechanism is needed to allow entities to
verify that an AS has been given permission by an IP address block
holder to advertise routes to that block. A ROA provides this
function.
A ROA is a digitally signed object that makes use of Cryptographic
Message Syntax (CMS) [RFC3852] as a standard encapsulation format.
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CMS was chosen to take advantage of existing open source software
available for processing messages in this format.
2. Basic Format
Using CMS syntax, a ROA is a type of signed-data object. The general
format of a CMS object is:
ContentInfo ::= SEQUENCE {
contentType ContentType,
content [0] EXPLICIT ANY DEFINED BY contentType }
ContentType ::= OBJECT IDENTIFIER
As a ROA is a signed-data object, it uses the corresponding OID,
1.2.840.113549.1.7.2. [RFC3852]
2.1. Signed-Data Content Type
According to the CMS standard, the signed-data content type shall
have 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
2.1.1. version
The version is the syntax version number. It MUST be 3,
corresponding to the signerInfo structure having version number 3.
2.1.2. digestAlgorithms
The digestAlgorithms set MUST include only SHA-256, the OID for which
is 2.16.840.1.101.3.4.2.1. [RFC4055] It MUST NOT contain any other
algorithms.
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2.1.3. encapContentInfo
encapContentInfo is the signed content, consisting of a content type
identifier and the content itself.
EncapsulatedContentInfo ::= SEQUENCE {
eContentType ContentType,
eContent [0] EXPLICIT OCTET STRING OPTIONAL }
ContentType ::= OBJECT IDENTIFIER
2.1.3.1. eContentType
The ContentType for a ROA is defined as routeOriginAttestation and
has the numerical value of 1.2.840.113549.1.9.16.1.24.
id-smime OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840)
rsadsi(113549) pkcs(1) pkcs9(9) 16 }
id-ct OBJECT INDENTIFIER ::= { id-smime 1 }
routeOriginAttestion OBJECT IDENTIFIER ::= { id-ct 24 }
2.1.3.2. eContent
The content of a ROA is a single AS that has been authorized by the
address space holder to originate routes and a list of one or more IP
address prefixes that will be advertised. If the address space
holder needs to authorize multiple ASes to advertise the same set of
address blocks, the holder issues multiple ROAs, one per AS number.
It is formally defined as:
RouteOriginAttestation ::= SEQUENCE {
version [0] INTEGER DEFAULT 0,
asID ASID,
ipAddrBlocks ROAIPAddrBlocks }
ASID ::= INTEGER
ROAIPAddrBlocks ::= SEQUENCE of ROAIPAddressFamily
ROAIPAddressFamily ::= SEQUENCE {
addressFamily OCTET STRING (SIZE (2..3)),
addressesOrRanges SEQUENCE OF IPAddressOrRange }
-- Only two address families are allowed: IPv4 and IPv6
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IPAddressOrRange ::= CHOICE {
addressPrefix IPAddress,
addressRange IPAddressRange }
IPAddressRange ::= SEQUENCE {
min IPAddress,
max IPAddress }
IPAddress ::= BIT STRING
2.1.4. certificates
The certificates field MAY be included. If so, it MUST contain only
the end entity certificate needed to validate this ROA. This
certificate should be present only if the ROA is being transmitted to
a relying party. Thus in the initial use of ROA's where they are
being made available to relying parties via a repository system, this
certificate SHOULD be omitted.
2.1.5. crls
The crls field MUST be omitted.
2.1.6. signerInfos
SignerInfo is defined under CMS as:
SignerInfo ::= SEQUENCE {
version CMSVersion,
sid SignerIdentifier,
digestAlgorithm DigestAlgorithmIdentifier,
signedAttrs [0] IMPLICIT SignedAttributes OPTIONAL,
signatureAlgorithm SignatureAlgorithmIdentifier,
signature SignatureValue,
unsignedAttrs [1] IMPLICIT UnsignedAttributes OPTIONAL }
2.1.6.1. version
The version number MUST be 3, corresponding with the choice of
SubjectKeyIdentifier for the sid.
2.1.6.2. sid
The sid is defined as:
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SignerIdentifier ::= CHOICE {
issuerAndSerialNumber IssuerAndSerialNumber,
subjectKeyIdentifier [0] SubjectKeyIdentifier }
For a ROA, the sid MUST be a SubjectKeyIdentifier.
2.1.6.3. digestAlgorithm
The digestAlgorithm MUST be SHA-256, the OID for which is
2.16.840.1.101.3.4.2.1. [RFC4055]
2.1.6.4. signedAttrs
signedAttrs MUST be omitted.
2.1.6.5. signatureAlgorithm
The signatureAlgorithm MUST be SHA-256 with RSA
(sha256WithRSAEncryption), the OID for which is
1.2.840.113549.1.1.11. [RFC4055]
2.1.6.6. signature
The signature value is defined as:
SignatureValue ::= OCTET STRING
The signature characteristics are defined by the digest and signature
algorithms.
2.1.6.7. unsignedAttrs
unsignedAttrs MUST be omitted.
3. Security Considerations
There is no assumption of confidentiality for the data in a ROA; it
is anticipated that ROAs will be stored in repositories that are
accessible to all ISPs, maybe to all Internet users. There is no
explicit authentication associated with a ROA, since the PKI used for
ROA validation provides authorization but not authentication.
Although the ROA is a signed, application layer object, there is no
intent to convey non-repudiation via a ROA.
The purpose of a ROA is to convey authorization for an AS to
originate a route to the prefix(es) in the ROA. Thus the integrity of
a ROA must be established. The ROA makes use of the CMS signed
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message format for integrity, and thus inherits the security
considerations associated with that data structure. The right of the
ROA signer to authorize the target AS to originate routes to the
prefix(es) is established through use of the address space and AS
number PKI described in [ARCH]. Specifically one must verify the
signature on the ROA using an X.509 certificate issued under this
PKI, and check that the prefix(es) in the ROA match those in the
address space extension in the certificate.
4. IANA Considerations
None.
5. Acknowledgments
The authors wish to thank Charles Gardiner and Russ Housley for their
help and contributions.
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6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3852] Housley, R., "Cryptographic Message Syntax", RFC 3852, July
2004.
[RFC4055] Schaad, J., Kaliski, B., and Housley, R., "Additional
Algorithms and Identifiers for RSA Cryptography for use in
the Internet X.509 Public Key Infrastructure Certificate
and Certificate Revocation List (CRL) Profile", RFC 4055,
June 2005.
6.2. Informative References
[RSA] Rivest, R., Shamir, A., and Adelman, L. M. 1978. A method
for obtaining digital signatures and public-key
cryptosystems. Commun. ACM 21, 2 (Feb.), 120-126.
[ARCH] Kent, S., Barnes, R., "An Infrastructure to Support Secure
Internet Routing," draft-ietf-sidr-arch-00.txt, February,
2007 (work in progress).
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Author's Addresses
Stephen Kent
BBN Technologies
10 Moulton Street
Cambridge MA 02138
USA
Phone: +1 (617) 873-3988
Email: skent@bbn.com
Derrick Kong
BBN Technologies
10 Moulton Street
Cambridge MA 02138
USA
Phone: +1 (617) 873-1951
Email: dkong@bbn.com
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