DNS Extentions O. Kolkman Internet-Draft RIPE NCC Expires: March 4, 2003 September 3, 2002 KEY RR Key Signing (KS) Flag draft-ietf-dnsext-keyrr-key-signing-flag-00.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 March 4, 2003. Copyright Notice Copyright (C) The Internet Society (2002). All Rights Reserved. Abstract The Introduction of the DS [1] record has introduced the concept of KEY signing and zone signing keys. In general, KEY signing keys are the keys that are pointed to by DS records and are the secure entry points to a zone. The key signing keys only sign the KEY RRset at the apex of a zone, zone signing keys sign all data in a zone. We propose a flag to distinguish the KEY signing key from other keys in the KEY RR set during DNSSEC operations. The key words "MAY","MAY NOT", "MUST", "MUST NOT", "REQUIRED", "RECOMMENDED", "SHOULD", and "SHOULD NOT" in this document are to be interpreted as described in RFC2119. Kolkman Expires March 4, 2003 [Page 1] Internet-Draft KEY RR Key Signing (KS) Flag September 2002 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. The Key Signing flag . . . . . . . . . . . . . . . . . . . . . . 3 3. DNSSEC Protocol changes . . . . . . . . . . . . . . . . . . . . 3 4. Operational Guidelines . . . . . . . . . . . . . . . . . . . . . 4 5. Security considerations . . . . . . . . . . . . . . . . . . . . 4 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 4 References . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5 Full Copyright Statement . . . . . . . . . . . . . . . . . . . . 6 Kolkman Expires March 4, 2003 [Page 2] Internet-Draft KEY RR Key Signing (KS) Flag September 2002 1. Introduction The Introduction of the DS record has introduced the concept of KEY signing keys. In general these are the keys that are pointed to by DS records and are the secure entry points to a zone. These key signing keys may also be configured in resolver systems that use zones as a root for a secure island. Early deployment tests have shown that during DNSSEC parent-child interactions it is useful to indicate which keys are to be used as the secure entry point to a zone. We introduce the Key Signing Key flag to indicate this special 'administrative' status of the key. During DNSSEC parent-child interactions it is useful to indicate which keys are to be used as the secure entry point to a zone. During key rollovers the KS-flag can be used by the parent to determine from which key the DS RR is to be generated from. 2. The Key Signing flag 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | flags |K| protocol | algorithm | | |S| | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | / / public key / / / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ KEY RR Format The bit 15th bit (TBD) in the flags field is assigned to be the key signing flag. If set the key is intended to be used as key signing key. If the bit is not set then no special meaning should be assigned. The 15th bit is currently reserved [2]. 3. DNSSEC Protocol changes The use of the KS flag does NOT change the DNS resolution and resolution protocol. The KS flag is only used to provide a hint about the different administrative properties and MUST NOT be used during the resolving process. Kolkman Expires March 4, 2003 [Page 3] Internet-Draft KEY RR Key Signing (KS) Flag September 2002 4. Operational Guidelines By setting the KS-flag on a particular key, zone administrators indicate that that key should be used as the secure entry point for their zone. Therefore zone administrators SHOULD set the bit only for zone keys that are used to sign the KEY RRset and are intended to act as the top of the chain of trust for their zone. Parent zone administrators and resolver administrators MAY choose to ignore the flag. Even with the KS-flag there is no mechanism to distinguish between keys that should be used by the parent to point DS records to or keys to be used by resolver administrators as statically configured keys. If the bit is modified during the lifetime of the key then this would have impact on the keytag and on the hash data in the DS RRs intending to point to this key. The bit SHOULD NOT be modified once the key has been put into use. 5. Security considerations The flag MUST NOT be used in the resolution protocol or to determine the security status of a key. The flag is to be used for administrative purposes only. If the flag is used to determine which key is to be used as the secure entry point then the trust in the key should be inferred from an existing DNS chain of trust or by an out of band key exchange. 6. Acknowledgments The ideas documented in this draft are inspired by communications we had with numerous people and ideas published by other folk, Jakob Schlyter and Olafur Gudmundsson and Dan Massey have been most substantial in providing ideas and feedback. This document saw the light during a workshop on DNSSEC operations hosted by USC/ISI. "Animal Farm; a Fairy Story" was first published by George Orwell in 1945, The version illustrated by Ralph Steadman is one we recommend ( ISBN: 0151002177 ). References [1] Gudmundsson, "Delegation Signer Resource Record", work in progress draft-ietf-dnsext-delegation-signer-08.txt, June 2002. Kolkman Expires March 4, 2003 [Page 4] Internet-Draft KEY RR Key Signing (KS) Flag September 2002 [2] Massey and Rose, "Limiting the Scope of the KEY Resource Record", work in progress draft-ietf-dnsext-restrict-key-for- dnssec-03, June 28 2002. Author's Address Olaf M. Kolkman RIPE NCC Singel 256 Amsterdam 1016 AB NL Phone: +31 20 535 4444 EMail: olaf@ripe.net URI: http://www.ripe.net/ Kolkman Expires March 4, 2003 [Page 5] Internet-Draft KEY RR Key Signing (KS) Flag September 2002 Full Copyright Statement Copyright (C) The Internet Society (2002). All Rights Reserved. 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