--- 1/draft-ietf-dnsext-dnssec-rsasha256-09.txt 2009-01-09 10:12:03.000000000 +0100 +++ 2/draft-ietf-dnsext-dnssec-rsasha256-10.txt 2009-01-09 10:12:03.000000000 +0100 @@ -1,76 +1,88 @@ DNS Extensions working group J. Jansen Internet-Draft NLnet Labs -Intended status: Standards Track December 04, 2008 -Expires: June 7, 2009 +Intended status: Standards Track January 08, 2009 +Expires: July 12, 2009 Use of SHA-2 algorithms with RSA in DNSKEY and RRSIG Resource Records for DNSSEC - draft-ietf-dnsext-dnssec-rsasha256-09 + draft-ietf-dnsext-dnssec-rsasha256-10 Status of this Memo - By submitting this Internet-Draft, each author represents that any - applicable patent or other IPR claims of which he or she is aware - have been or will be disclosed, and any of which he or she becomes - aware will be disclosed, in accordance with Section 6 of BCP 79. + This Internet-Draft is submitted to IETF in full conformance with the + provisions of BCP 78 and BCP 79. 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 June 7, 2009. + This Internet-Draft will expire on July 12, 2009. + +Copyright Notice + + Copyright (c) 2009 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. Abstract This document describes how to produce RSA/SHA-256 and RSA/SHA-512 DNSKEY and RRSIG resource records for use in the Domain Name System Security Extensions (DNSSEC, RFC 4033, RFC 4034, and RFC 4035). Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. DNSKEY Resource Records . . . . . . . . . . . . . . . . . . . . 3 2.1. RSA/SHA-256 DNSKEY Resource Records . . . . . . . . . . . . 3 - 2.2. RSA/SHA-512 DNSKEY Resource Records . . . . . . . . . . . . 4 + 2.2. RSA/SHA-512 DNSKEY Resource Records . . . . . . . . . . . . 3 3. RRSIG Resource Records . . . . . . . . . . . . . . . . . . . . 4 3.1. RSA/SHA-256 RRSIG Resource Records . . . . . . . . . . . . 4 - 3.2. RSA/SHA-512 RRSIG Resource Records . . . . . . . . . . . . 5 + 3.2. RSA/SHA-512 RRSIG Resource Records . . . . . . . . . . . . 4 4. Deployment Considerations . . . . . . . . . . . . . . . . . . . 5 4.1. Key Sizes . . . . . . . . . . . . . . . . . . . . . . . . . 5 4.2. Signature Sizes . . . . . . . . . . . . . . . . . . . . . . 5 5. Implementation Considerations . . . . . . . . . . . . . . . . . 5 5.1. Support for SHA-2 signatures . . . . . . . . . . . . . . . 5 + 5.2. Support for NSEC3 Denial of Existence . . . . . . . . . . . 5 + 5.2.1. NSEC3 in Authoritative servers . . . . . . . . . . . . 5 + 5.2.2. NSEC3 in Validators . . . . . . . . . . . . . . . . . . 5 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 7.1. SHA-1 versus SHA-2 Considerations for RRSIG Resource Records . . . . . . . . . . . . . . . . . . . . . . . . . . 6 7.2. Signature Type Downgrade Attacks . . . . . . . . . . . . . 6 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 9.1. Normative References . . . . . . . . . . . . . . . . . . . 7 9.2. Informative References . . . . . . . . . . . . . . . . . . 7 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 8 - Intellectual Property and Copyright Statements . . . . . . . . . . 9 1. Introduction The Domain Name System (DNS) is the global hierarchical distributed database for Internet Naming. The DNS has been extended to use cryptographic keys and digital signatures for the verification of the authenticity and integrity of its data. RFC 4033 [RFC4033], RFC 4034 [RFC4034], and RFC 4035 [RFC4035] describe these DNS Security Extensions, called DNSSEC. @@ -96,38 +108,28 @@ 2. DNSKEY Resource Records The format of the DNSKEY RR can be found in RFC 4034 [RFC4034]. RFC 3110 [RFC3110] describes the use of RSA/SHA-1 for DNSSEC signatures. 2.1. RSA/SHA-256 DNSKEY Resource Records RSA public keys for use with RSA/SHA-256 are stored in DNSKEY resource records (RRs) with the algorithm number {TBA1}. - For use with NSEC3 [RFC5155], the algorithm number for RSA/SHA-256 - will be {TBA2}. The use of a different algorithm number to - differentiate between the use of NSEC and NSEC3 is in keeping with - the approach adopted in RFC5155. - For interoperability, as in RFC 3110 [RFC3110], the key size of RSA/ SHA-256 keys MUST NOT be less than 512 bits, and MUST NOT be more than 4096 bits. 2.2. RSA/SHA-512 DNSKEY Resource Records RSA public keys for use with RSA/SHA-512 are stored in DNSKEY - resource records (RRs) with the algorithm number {TBA3}. - - For use with NSEC3, the algorithm number for RSA/SHA-512 will be - {TBA4}. The use of a different algorithm number to differentiate - between the use of NSEC and NSEC3 is in keeping with the approach - adopted in RFC5155. + resource records (RRs) with the algorithm number {TBA2}. The key size of RSA/SHA-512 keys MUST NOT be less than 1024 bits, and MUST NOT be more than 4096 bits. 3. RRSIG Resource Records The value of the signature field in the RRSIG RR follows the RSASSA- PKCS1-v1_5 signature scheme, and is calculated as follows. The values for the RDATA fields that precede the signature data are specified in RFC 4034 [RFC4034]. @@ -151,33 +153,31 @@ The "prefix" is intended to make the use of standard cryptographic libraries easier. These specifications are taken directly from the specifications of RSASSA-PKCS1-v1_5 in PKCS #1 v2.1 section 8.2 [RFC3447], and EMSA-PKCS1-v1_5 encoding in PKCS #1 v2.1 section 9.2 [RFC3447]. The prefixes for the different algorithms are specified below. 3.1. RSA/SHA-256 RRSIG Resource Records RSA/SHA-256 signatures are stored in the DNS using RRSIG resource - records (RRs) with algorithm number {TBA1} for use with NSEC, or - {TBA2} for use with NSEC3. + records (RRs) with algorithm number {TBA1}. The prefix is the ASN.1 DER SHA-256 algorithm designator prefix as specified in PKCS #1 v2.1 [RFC3447]: hex 30 31 30 0d 06 09 60 86 48 01 65 03 04 02 01 05 00 04 20 3.2. RSA/SHA-512 RRSIG Resource Records RSA/SHA-512 signatures are stored in the DNS using RRSIG resource - records (RRs) with algorithm number {TBA3} for use with NSEC, or - {TBA4} for use with NSEC3. + records (RRs) with algorithm number {TBA2}. The prefix is the ASN.1 DER SHA-512 algorithm designator prefix as specified in PKCS #1 v2.1 [RFC3447]: hex 30 51 30 0d 06 09 60 86 48 01 65 03 04 02 03 05 00 04 40 4. Deployment Considerations 4.1. Key Sizes @@ -195,33 +195,50 @@ RSA/SHA256 or RSA/SHA512 will have the same size as those produced with RSA/SHA1, if the keys have the same length. 5. Implementation Considerations 5.1. Support for SHA-2 signatures DNSSEC aware implementations SHOULD be able to support RRSIG resource records with the RSA/SHA-2 algorithms. +5.2. Support for NSEC3 Denial of Existence + + Note that these algorithms have no aliases to signal NSEC3 [RFC5155] + denial of existence. The aliases mechanism used in RFC 5155 was to + protect implementations predating that RFC from encountering records + they could not know about. + +5.2.1. NSEC3 in Authoritative servers + + An authoritative server that does not implement NSEC3 MAY still serve + zones that use RSA/SHA2 with NSEC. + +5.2.2. NSEC3 in Validators + + A DNSSEC validator that implements RSA/SHA2 MUST be able to handle + both NSEC and NSEC3 [RFC5155] negative answers. If this is not the + case, the validator MUST treat a zone signed with RSA/SHA256 or RSA/ + SHA512 as signed with an unknown algorithm, and thus as insecure. + 6. IANA Considerations This document updates the IANA registry "DNS SECURITY ALGORITHM NUMBERS -- per [RFC4035]" (http://www.iana.org/assignments/dns-sec-alg-numbers). The following entries are added to the registry: Zone Value Algorithm Mnemonic Signing References {TBA1} RSA/SHA-256 RSASHA256 y {this memo} - {TBA2} RSA/SHA-256-NSEC3 RSASHA256NSEC3 y {this memo} - {TBA3} RSA/SHA-512 RSASHA512 y {this memo} - {TBA4} RSA/SHA-512-NSEC3 RSASHA512NSEC3 y {this memo} + {TBA2} RSA/SHA-512 RSASHA512 y {this memo} 7. Security Considerations 7.1. SHA-1 versus SHA-2 Considerations for RRSIG Resource Records Users of DNSSEC are encouraged to deploy SHA-2 as soon as software implementations allow for it. SHA-2 is widely believed to be more resilient to attack than SHA-1, and confidence in SHA-1's strength is being eroded by recently-announced attacks. Regardless of whether or not the attacks on SHA-1 will affect DNSSEC, it is believed (at the @@ -304,50 +321,10 @@ Author's Address Jelte Jansen NLnet Labs Kruislaan 419 Amsterdam 1098VA NL Email: jelte@NLnetLabs.nl URI: http://www.nlnetlabs.nl/ - -Full Copyright Statement - - Copyright (C) The IETF Trust (2008). - - This document is subject to the rights, licenses and restrictions - contained in BCP 78, and except as set forth therein, the authors - retain all their rights. - - This document and the information contained herein are provided on an - "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS - OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND - THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS - OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF - THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED - WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. - -Intellectual Property - - The IETF takes no position regarding the validity or scope of any - Intellectual Property Rights or other rights that might be claimed to - pertain to the implementation or use of the technology described in - this document or the extent to which any license under such rights - might or might not be available; nor does it represent that it has - made any independent effort to identify any such rights. 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