7Internet Engineering Task Force (IETF) P. Hoffman
8Request for Comments: 6014 VPN Consortium
9Updates: 4033, 4034, 4035 November 2010
10Category: Standards Track
14 Cryptographic Algorithm Identifier Allocation for DNSSEC
18 This document specifies how DNSSEC cryptographic algorithm
19 identifiers in the IANA registries are allocated. It changes the
20 requirement from "standard required" to "RFC Required". It does not
21 change the list of algorithms that are recommended or required for
22 DNSSEC implementations.
26 This is an Internet Standards Track document.
28 This document is a product of the Internet Engineering Task Force
29 (IETF). It represents the consensus of the IETF community. It has
30 received public review and has been approved for publication by the
31 Internet Engineering Steering Group (IESG). Further information on
32 Internet Standards is available in Section 2 of RFC 5741.
34 Information about the current status of this document, any errata,
35 and how to provide feedback on it may be obtained at
36 http://www.rfc-editor.org/info/rfc6014.
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60RFC 6014 DNSSEC Alg. Allocation November 2010
65 Copyright (c) 2010 IETF Trust and the persons identified as the
66 document authors. All rights reserved.
68 This document is subject to BCP 78 and the IETF Trust's Legal
69 Provisions Relating to IETF Documents
70 (http://trustee.ietf.org/license-info) in effect on the date of
71 publication of this document. Please review these documents
72 carefully, as they describe your rights and restrictions with respect
73 to this document. Code Components extracted from this document must
74 include Simplified BSD License text as described in Section 4.e of
75 the Trust Legal Provisions and are provided without warranty as
76 described in the Simplified BSD License.
78 This document may contain material from IETF Documents or IETF
79 Contributions published or made publicly available before November
80 10, 2008. The person(s) controlling the copyright in some of this
81 material may not have granted the IETF Trust the right to allow
82 modifications of such material outside the IETF Standards Process.
83 Without obtaining an adequate license from the person(s) controlling
84 the copyright in such materials, this document may not be modified
85 outside the IETF Standards Process, and derivative works of it may
86 not be created outside the IETF Standards Process, except to format
87 it for publication as an RFC or to translate it into languages other
92 [RFC2535] specifies that the IANA registry for DNS Security Algorithm
93 Numbers be updated by IETF Standards Action only, with the exception
94 of two values -- 253 and 254. In essence, this means that for an
95 algorithm to get its own entry in the registry, the algorithm must be
96 defined in an RFC on the Standards Track as defined in [RFC2026].
97 The requirement from RFC 2535 is repeated in [RFC3755] and the
98 combination of [RFC4033], [RFC4034], and [RFC4035].
100 RFC 2535 allows algorithms that are not on the Standards Track to use
101 private values 253 and 254 in signatures. In each case, an
102 unregistered private name must be included with each use of the
103 algorithm in order to differentiate different algorithms that use the
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116RFC 6014 DNSSEC Alg. Allocation November 2010
1192. Requirements for Assignments in the DNS Security Algorithm Numbers
122 This document changes the requirement for registration from requiring
123 a Standards Track RFC to requiring a published RFC of any type.
124 There are two reasons for relaxing the requirement:
126 o There are some algorithms that are useful that may not be able to
127 be in a Standards Track RFC. For any number of reasons, an
128 algorithm might not have been evaluated thoroughly enough to be
129 able to be put on the Standards Track. Another example is that
130 the algorithm might have unclear intellectual property rights that
131 prevents the algorithm from being put on the Standards Track.
133 o Although the size of the registry is restricted (about 250
134 entries), new algorithms are proposed infrequently. It could
135 easily be many decades before there is any reason to consider
136 restricting the registry again.
138 Some developers will care about the standards level of the RFCs that
139 are in the registry. The registry has been updated to reflect the
140 current standards level of each algorithm listed.
142 To address concerns about the registry eventually filling up, the
143 IETF should re-evaluate the requirements for entry into this registry
144 when approximately 120 of the registry entries have been assigned.
145 That evaluation may lead to tighter restrictions or a new mechanism
146 for extending the size of the registry. In order to make this
147 evaluation more likely, IANA has marked about half of the currently
148 available entries as "Reserved" in order to make the timing for that
149 re-evaluation more apparent.
151 The private-use values, 253 and 254, are still useful for developers
152 who want to test, in private, algorithms for which there is no RFC.
153 This document does not change the semantics of those two values.
1553. Expectations for Implementations
157 It is important to note that, according to RFC 4034, DNSSEC
158 implementations are not expected to include all of the algorithms
159 listed in the IANA registry; in fact, RFC 4034 and the IANA registry
160 list an algorithm that implementations should not include. This
161 document does nothing to change the expectation that there will be
162 items listed in the IANA registry that need not be (and in some
163 cases, should not be) included in all implementations.
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172RFC 6014 DNSSEC Alg. Allocation November 2010
175 There are many reasons why a DNSSEC implementation might not include
176 one or more of the algorithms listed, even those on the Standards
177 Track. In order to be compliant with RFC 4034, an implementation
178 only needs to implement the algorithms listed as mandatory to
179 implement in that standard, or updates to that standard. This
180 document does nothing to change the list of mandatory-to-implement
181 algorithms in RFC 4034. This document does not change the
182 requirements for when an algorithm becomes mandatory to implement.
183 Such requirements should come in a separate, focused document.
185 It should be noted that the order of algorithms in the IANA registry
186 does not signify or imply cryptographic strength or preference.
1884. IANA Considerations
190 This document updates allocation requirements for unassigned values
191 in the "Domain Name System Security (DNSSEC) Algorithm Numbers"
192 registry located at http://www.iana.org/assignments/
193 dns-sec-alg-numbers, in the sub-registry titled "DNS Security
194 Algorithm Numbers". The registration procedure for values that are
195 assigned after this document is published is "RFC Required".
197 IANA has marked values 123 through 251 as "Reserved". The registry
198 notes that this reservation is made in RFC 6014 (this RFC) so that
199 when most of the unreserved values are taken, future users and IANA
200 will have a pointer to where the reservation originated and its
203 IANA has added a textual notation to the "References" column in the
204 registry that gives the current standards status for each RFC that is
205 listed in the registry.
2075. Security Considerations
209 An algorithm described in an RFC that is not on the Standards Track
210 may have weaker security than one that is on the Standards Track; in
211 fact, that may be the reason that the algorithm was not allowed on
212 Standards Track. Note, however, that not being on the Standards
213 Track does not necessarily mean that an algorithm is weaker.
214 Conversely, algorithms that are on the Standards Track should not
215 necessarily be considered better than algorithms that are not on the
216 Standards Track. There are other reasons (such as intellectual
217 property concerns) that can keep algorithms that are widely
218 considered to be strong off the Standards Track.
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228RFC 6014 DNSSEC Alg. Allocation November 2010
2336.1. Normative References
235 [RFC2535] Eastlake, D., "Domain Name System Security Extensions",
236 RFC 2535, March 1999.
238 [RFC3755] Weiler, S., "Legacy Resolver Compatibility for Delegation
239 Signer (DS)", RFC 3755, May 2004.
241 [RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.
242 Rose, "DNS Security Introduction and Requirements",
243 RFC 4033, March 2005.
245 [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S.
246 Rose, "Resource Records for the DNS Security Extensions",
247 RFC 4034, March 2005.
249 [RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S.
250 Rose, "Protocol Modifications for the DNS Security
251 Extensions", RFC 4035, March 2005.
2536.2. Informative References
255 [RFC2026] Bradner, S., "The Internet Standards Process -- Revision
256 3", BCP 9, RFC 2026, October 1996.
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287Appendix A. Experimental and Documentation Values
289 During the early discussion of this document, it was proposed that
290 maybe there should be a small number of values reserved for
291 "experimental" purposes. This proposal was not included in this
292 document because of the long history in the IETF of experimental
293 values that became permanent. That is, a developer would release
294 (maybe "experimentally") a version of software that had the
295 experimental value associated with a particular extension,
296 competitors would code their systems to test interoperability, and
297 then no one wanted to change the values in their software to the
298 "real" value that was later assigned.
300 There was also a proposal that IANA should reserve two values to be
301 used in documentation only, similar to the way that "example.com" has
302 been reserved as a domain name. That proposal was also not included
303 in this document because all values need to be associated with some
304 algorithm, and there is no problem with having examples that point to
305 commonly deployed algorithms.
312 EMail: paul.hoffman@vpnc.org
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