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Internet Engineering Task Force (IETF)                        P. HoffmanRequest for Comments: 6014                                VPN ConsortiumUpdates:4033,4034,4035                                  November 2010Category: Standards TrackISSN: 2070-1721Cryptographic Algorithm Identifier Allocation for DNSSECAbstract   This document specifies how DNSSEC cryptographic algorithm   identifiers in the IANA registries are allocated.  It changes the   requirement from "standard required" to "RFC Required".  It does not   change the list of algorithms that are recommended or required for   DNSSEC implementations.Status of This Memo   This is an Internet Standards Track document.   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).  Further information on   Internet Standards is available inSection 2 of RFC 5741.   Information about the current status of this document, any errata,   and how to provide feedback on it may be obtained athttp://www.rfc-editor.org/info/rfc6014.Hoffman                      Standards Track                    [Page 1]

RFC 6014                 DNSSEC Alg. Allocation            November 2010Copyright Notice   Copyright (c) 2010 IETF Trust and the persons identified as the   document authors.  All rights reserved.   This document is subject toBCP 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.1.  Introduction   [RFC2535] specifies that the 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 the Standards Track as defined in [RFC2026].   The requirement fromRFC 2535 is repeated in [RFC3755] and the   combination of [RFC4033], [RFC4034], and [RFC4035].RFC 2535 allows algorithms that are not on the 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.Hoffman                      Standards Track                    [Page 2]

RFC 6014                 DNSSEC Alg. Allocation            November 20102.  Requirements for Assignments in the DNS Security Algorithm Numbers    Registry   This document changes the requirement for registration from requiring   a Standards Track RFC to requiring a published RFC of any type.   There are two reasons for relaxing the requirement:   o  There are some algorithms that are useful that may not be able to      be in a Standards Track RFC.  For any number of reasons, an      algorithm might not have been evaluated thoroughly enough to be      able to be put on the Standards Track.  Another example is that      the algorithm might have unclear intellectual property rights that      prevents the algorithm from being put on the Standards Track.   o  Although the size of the registry is restricted (about 250      entries), new algorithms are proposed infrequently.  It could      easily be many decades before there is any reason to consider      restricting the registry again.   Some developers will care about the standards level of the RFCs that   are in the registry.  The registry has been updated to reflect the   current standards level of each algorithm listed.   To address concerns about the registry eventually filling up, the   IETF should re-evaluate the requirements for entry into this registry   when approximately 120 of the registry entries have been assigned.   That evaluation may lead to tighter restrictions or a new mechanism   for extending the size of the registry.  In order to make this   evaluation more likely, IANA has marked about half of the currently   available entries as "Reserved" in order to make the timing for that   re-evaluation more apparent.   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 toRFC 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.Hoffman                      Standards Track                    [Page 3]

RFC 6014                 DNSSEC Alg. Allocation            November 2010   There are many reasons why a DNSSEC implementation might not include   one or more of the algorithms listed, even those on the Standards   Track.  In order to be compliant withRFC 4034, an implementation   only needs to implement the algorithms listed as mandatory to   implement in that standard, or updates to that standard.  This   document does nothing to change the list of mandatory-to-implement   algorithms inRFC 4034.  This document does not change the   requirements for when an algorithm becomes mandatory to implement.   Such requirements should come in a separate, focused document.   It should be noted that the order of algorithms in the IANA registry   does not signify or imply cryptographic strength or preference.4.  IANA Considerations   This document updates allocation requirements for unassigned values   in the "Domain Name System Security (DNSSEC) Algorithm Numbers"   registry located athttp://www.iana.org/assignments/dns-sec-alg-numbers, in the sub-registry titled "DNS Security   Algorithm Numbers".  The registration procedure for values that are   assigned after this document is published is "RFC Required".   IANA has marked values 123 through 251 as "Reserved".  The registry   notes that this reservation is made inRFC 6014 (this RFC) so that   when most of the unreserved values are taken, future users and IANA   will have a pointer to where the reservation originated and its   purpose.   IANA has added 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.5.  Security Considerations   An algorithm described in an RFC that is not on the Standards Track   may have weaker security than one that is on the Standards Track; in   fact, that may be the reason that the algorithm was not allowed on   Standards Track.  Note, however, that not being on the Standards   Track does not necessarily mean that an algorithm is weaker.   Conversely, algorithms that are on the Standards Track should not   necessarily be considered better than algorithms that are not on the   Standards Track.  There are other reasons (such as intellectual   property concerns) that can keep algorithms that are widely   considered to be strong off the Standards Track.Hoffman                      Standards Track                    [Page 4]

RFC 6014                 DNSSEC Alg. Allocation            November 20106.  References6.1.  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.   [RFC4033]  Arends, R., Austein, R., Larson, M., Massey, D., and S.              Rose, "DNS Security Introduction and Requirements",RFC 4033, March 2005.   [RFC4034]  Arends, R., Austein, R., Larson, M., Massey, D., and S.              Rose, "Resource Records for the DNS Security Extensions",RFC 4034, March 2005.   [RFC4035]  Arends, R., Austein, R., Larson, M., Massey, D., and S.              Rose, "Protocol Modifications for the DNS Security              Extensions",RFC 4035, March 2005.6.2.  Informative References   [RFC2026]  Bradner, S., "The Internet Standards Process -- Revision              3",BCP 9,RFC 2026, October 1996.Hoffman                      Standards Track                    [Page 5]

RFC 6014                 DNSSEC Alg. Allocation            November 2010Appendix 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   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.Author's Address   Paul Hoffman   VPN Consortium   EMail: paul.hoffman@vpnc.orgHoffman                      Standards Track                    [Page 6]