Network Working Group P. Hoffman Internet-Draft VPN Consortium Updates: 2535, 3755, 4034 August 27, 2009 (if approved) Intended status: Standards Track Expires: February 28, 2010 Cryptographic Algorithm Identifier Allocation for DNSSEC draft-hoffman-dnssec-alg-allocation-01 Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. 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. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on February 28, 2010. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. Hoffman Expires February 28, 2010 [Page 1]
Internet-Draft DNSSEC Alg. Allocation August 2009 This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Abstract This document specifies how DNSSEC cryptographic algorithm identifiers in the IANA registries are allocated. It changes the rule from "standard required" to "RFC required". 1. Introduction [RFC2535] specifies that that IANA registry for DNS Security Algorithm Numbers be updated by IETF Standards Action only, with the exception of two values 253 and 254. In essence, this means that for an algorithm to get its own entry in the registry, the algorithm must be defined in an RFC on Standards Track as defined in [RFC2026]. The rule from RFC 2535 is repeated in [RFC3755] and [RFC4034]. RFC 2535 allows algorithms that are not on standards track to use private values 253 and 254 in signatures. In each case, an unregistered private name must be included with each use of the algorithm in order to differentiate different algorithms that use the value. 2. Requirements for Assignments in the DNS Security Algorithm Numbers Registry This document changes the rule for registration from requiring a Standards Track RFC to requiring a published RFC of any type. There are two reasons for relaxing the rule: o There are some algorithms that are useful that may not be able to be in a Standards Track RFC. For example, an algorithm might be sponsored by a government and use cryptography that has not been evaluated thoroughly enough to be able to be put on Standards Track. Another example is that the algorithm might have an unclear intellectual property rights situation, and that prevents the algorithm from being put on Standards Track. o Although the size of the registry is quite restricted (about 250 entries), new algorithms are proposed relatively rarely. It could easily be many decades before there is any reason to consider restricting the registry again. Hoffman Expires February 28, 2010 [Page 2]
Internet-Draft DNSSEC Alg. Allocation August 2009 Some developers will care about the standards level of the RFCs that are in the registry. The registry should reflect the current standards level of each algorithm listed. Because the size of the registry is smaller than many IETF registries, and because some members of the DNS community have expressed concern about the registry eventually filling up, the IETF should re-evaluate the requirements for entry into this registry when the registry is about half full. That evaluation may lead to tighter restrictions or a new mechanism for essentially extending the size of the registry. The private-use values, 253 and 254, are still useful for developers who want to test, in private, algorithms for which there is no RFC. This document does not change the semantics of those two values. 3. Expectations For Implementations It is important to note that, according to RFC 4034, DNSSEC implementations are not expected to include all of the algorithms listed in the IANA registry; in fact, RFC 4034 and the IANA registry list an algorithm that implementations should not include. This document does nothing to change the expectation that there will be items listed in the IANA registry that need not be (and in some cases, should not be) included in all implementations. There are many reasons why a DNSSEC implementation might not include one or more of the algorithms listed, even those on Standards Track. In order to be compliant with the RFC 4034, an implementation only needs to implement the algorithms listed as mandatory to implement in the that standard, or updates to that standard. This document does nothing to change the list of mandatory to implement algorithms in RFC 4034. 4. IANA Considerations This document updates allocation rules for unassigned values in the "Domain Name System Security (DNSSEC) Algorithm Numbers" registry located at http://www.iana.org/assignments/dns-sec-alg-numbers/ dns-sec-alg-numbers.xhtml, in the sub-registry titled "DNS Security Algorithm Numbers". The registration procedure for values that were not assigned before this document is published is "RFC Required". IANA is requested to add a textual notation to the "References" column in the registry that gives the current standards status for each RFC that is listed in the registry. Hoffman Expires February 28, 2010 [Page 3]
Internet-Draft DNSSEC Alg. Allocation August 2009 5. Security Considerations An algorithm described in an RFC that is not on Standards Track may have weaker security than one that is on standards track; in fact, that may be the reason that the algorithm was not allowed on Standards Track. Note, however, that not being on Standards Track does not necessarily mean that an algorithm is weaker. There are other reasons (such as intellectual property concerns) that can keep algorithms that are widely considered to be strong off of Standards Track. 6. References 6.1. Normative References [RFC2535] Eastlake, D., "Domain Name System Security Extensions", RFC 2535, March 1999. [RFC3755] Weiler, S., "Legacy Resolver Compatibility for Delegation Signer (DS)", RFC 3755, May 2004. [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Resource Records for the DNS Security Extensions", RFC 4034, March 2005. 6.2. Informative References [RFC2026] Bradner, S., "The Internet Standards Process -- Revision 3", BCP 9, RFC 2026, October 1996. Appendix A. Experimental and Documentation Values During the early discussion of this document, it was proposed that maybe there should be a small number of values reserved for "experimental" purposes. This proposal was not included in this document because of the long history in the IETF of experimental values that became permanent. That is, a developer would release (maybe "experimentally") a version of software that had the experimental value associated with a particular extension, competitors would code their systems to test interoperability, and then no one wanted to change the values in their software to the "real" value that was later assigned. There was also a proposal that IANA should reserve two values to be used in documentation only, similar to the way that "example.com" has been reserved as a domain name. That proposal was also not included Hoffman Expires February 28, 2010 [Page 4]
Internet-Draft DNSSEC Alg. Allocation August 2009 in this document because all values need to be associated with some algorithm, and there is no problem with having examples that point to commonly-deployed algorithms. Appendix B. Change History This section is to be removed before publication as an RFC. B.1. Differences between -00 and -01 A few editorial nits that really should have been caught in the -00. Added the section on "Expectations For Implementations" to clarify that this document is not changing any such expectations or updating that part of RFC 4034. Author's Address Paul Hoffman VPN Consortium Email: paul.hoffman@vpnc.org Hoffman Expires February 28, 2010 [Page 5]