Internet Engineering Task Force (IETF) T. Heer Request for Comments: 6253 COMSYS, RWTH Aachen University Updates: 5201 S. Varjonen Category: Experimental Helsinki Institute for Information Technology ISSN: 2070-1721 May 2011 Host Identity Protocol Certificates
AbstractThe Certificate (CERT) parameter is a container for digital certificates. It is used for carrying these certificates in Host Identity Protocol (HIP) control packets. This document specifies the CERT parameter and the error signaling in case of a failed verification. Additionally, this document specifies the representations of Host Identity Tags in X.509 version 3 (v3) and Simple Public Key Infrastructure (SPKI) certificates. The concrete use of certificates, including how certificates are obtained, requested, and which actions are taken upon successful or failed verification, is specific to the scenario in which the certificates are used. Hence, the definition of these scenario- specific aspects is left to the documents that use the CERT parameter. This document updates RFC 5201. Status of This Memo This document is not an Internet Standards Track specification; it is published for examination, experimental implementation, and evaluation. This document defines an Experimental Protocol for the Internet community. 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). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see 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/rfc6253.
Copyright Notice Copyright (c) 2011 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. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. RFC5201] defines a new cryptographic namespace based on asymmetric cryptography. The identity of each host is derived from a public key, allowing hosts to digitally sign data and issue certificates with their private key. This document specifies the CERT parameter, which is used to transmit digital certificates in HIP. It fills the placeholder specified in Section 5.2 of [RFC5201] and thus updates [RFC5201]. RFC2119].
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cert group | Cert count | Cert ID | Cert type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Certificate / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / | Padding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type 768 Length Length in octets, excluding Type, Length, and Padding. Cert group Group ID grouping multiple related CERT parameters. Cert count Total count of certificates that are sent, possibly in several consecutive HIP control packets. Cert ID The sequence number for this certificate. Cert Type Indicates the type of the certificate. Padding Any Padding, if necessary, to make the TLV a multiple of 8 bytes. The certificates MUST use the algorithms defined in [RFC5201] as the signature and hash algorithms. The following certificate types are defined: +--------------------------------+-------------+ | Cert format | Type number | +--------------------------------+-------------+ | Reserved | 0 | | X.509 v3 | 1 | | SPKI | 2 | | Hash and URL of X.509 v3 | 3 | | Hash and URL of SPKI | 4 | | LDAP URL of X.509 v3 | 5 | | LDAP URL of SPKI | 6 | | Distinguished Name of X.509 v3 | 7 | | Distinguished Name of SPKI | 8 | +--------------------------------+-------------+ The next sections outline the use of Host Identity Tags (HITs) in X.509 v3 and in Simple Public Key Infrastructure (SPKI) certificates. X.509 v3 certificates and the handling procedures are defined in [RFC5280]. The wire format for X.509 v3 is the Distinguished Encoding Rules format as defined in [X.690]. The SPKI, the handling procedures, and the formats are defined in [RFC2693].
Hash and Uniform Resource Locator (URL) encodings (3 and 4) are used as defined in Section 3.6 of [RFC5996]. Using hash and URL encodings results in smaller HIP control packets than by including the certificate(s), but requires the receiver to resolve the URL or check a local cache against the hash. Lightweight Directory Access Protocol (LDAP) URL encodings (5 and 6) are used as defined in [RFC4516]. Using LDAP URL encoding results in smaller HIP control packets but requires the receiver to retrieve the certificate or check a local cache against the URL. Distinguished Name (DN) encodings (7 and 8) are represented by the string representation of the certificate's subject DN as defined in [RFC4514]. Using the DN encoding results in smaller HIP control packets, but requires the receiver to retrieve the certificate or check a local cache against the DN. RFC4843]. When the Host Identifier (HI) is used to sign the certificate, the respective HIT MUST be placed into the Issuer Alternative Name (IAN) extension using the GeneralName form iPAddress as defined in [RFC5280]. When the certificate is issued for a HIP host, identified by a HIT and HI, the respective HIT MUST be placed into the Subject Alternative Name (SAN) extension using the GeneralName form iPAddress, and the full HI is presented as the subject's public key info as defined in [RFC5280]. The following examples illustrate how HITs are presented as issuer and subject in the X.509 v3 extension alternative names. Format of X509v3 extensions: X509v3 Issuer Alternative Name: IP Address:hit-of-issuer X509v3 Subject Alternative Name: IP Address:hit-of-subject Example X509v3 extensions: X509v3 Issuer Alternative Name: IP Address:2001:14:6cf:fae7:bb79:bf78:7d64:c056 X509v3 Subject Alternative Name: IP Address:2001:1c:5a14:26de:a07c:385b:de35:60e3 Appendix B shows a full example of an X.509 v3 certificate with HIP content.
As another example, consider a managed Public Key Infrastructure (PKI) environment in which the peers have certificates that are anchored in (potentially different) managed trust chains. In this scenario, the certificates issued to HIP hosts are signed by intermediate Certification Authorities (CAs) up to a root CA. In this example, the managed PKI environment is neither HIP aware, nor can it be configured to compute HITs and include them in the certificates. When HIP communications are established, the HIP hosts not only need to send their identity certificates (or pointers to their certificates), but also the chain of intermediate CAs (or pointers to the CAs) up to the root CA, or to a CA that is trusted by the remote peer. This chain of certificates MUST be sent in a Cert group as specified in Section 2. The HIP peers validate each other's certificates and compute peer HITs based on the certificate public keys. Appendix A shows a full example of a SPKI certificate with HIP content. Section 5 of [RFC5280]. Revocation of SPKI certificates is handled as defined in Section 5 of [RFC2693].
RFC5201]. This parameter is defined in Section 2 with type 768. The parameter type number is also defined in [RFC5201]. The CERT parameter has an 8-bit unsigned integer field for different certificate types, for which IANA has created and now maintains a new sub-registry entitled "HIP Certificate Types" under the "Host Identity Protocol (HIP) Parameters". Initial values for the Certificate type registry are given in Section 2. New values for the Certificate types from the unassigned space are assigned through IETF Review. In Section 6, this document defines two new types for the "NOTIFY Message Types" sub-registry under "Host Identity Protocol (HIP) Parameters".
RFC2693] and for X.509 v3 in [RFC5280]. Section 3. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2693] Ellison, C., Frantz, B., Lampson, B., Rivest, R., Thomas, B., and T. Ylonen, "SPKI Certificate Theory", RFC 2693, September 1999. [RFC4514] Zeilenga, K., Ed., "Lightweight Directory Access Protocol (LDAP): String Representation of Distinguished Names", RFC 4514, June 2006. [RFC4516] Smith, M., Ed., and T. Howes, "Lightweight Directory Access Protocol (LDAP): Uniform Resource Locator", RFC 4516, June 2006. [RFC4843] Nikander, P., Laganier, J., and F. Dupont, "An IPv6 Prefix for Overlay Routable Cryptographic Hash Identifiers (ORCHID)", RFC 4843, April 2007. [RFC5201] Moskowitz, R., Nikander, P., Jokela, P., Ed., and T. Henderson, "Host Identity Protocol", RFC 5201, April 2008.
[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. [RFC5996] Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen, "Internet Key Exchange Protocol Version 2 (IKEv2)", RFC 5996, September 2010. [X.690] ITU-T, "Recommendation X.690 (2002) | ISO/IEC 8825-1:2002, Information Technology - ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)", July 2002.
http://www.comsys.rwth-aachen.de/team/tobias-heer/ Samu Varjonen Helsinki Institute for Information Technology Gustaf Haellstroemin katu 2b Helsinki Finland EMail: firstname.lastname@example.org URI: http://www.hiit.fi