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.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS 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.
Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
Kolkman Expires March 4, 2003 [Page 6]