Network Time Protocol Version 4: Autokey Specification
RFC 5906
Document | Type |
RFC - Informational
(June 2010; Errata)
Was draft-ietf-ntp-autokey (ntp WG)
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Authors | David Mills , Brian Haberman | ||
Last updated | 2020-01-21 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized with errata bibtex | ||
Reviews | |||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 5906 (Informational) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Ralph Droms | ||
Send notices to | (None) |
Internet Engineering Task Force (IETF) B. Haberman, Ed. Request for Comments: 5906 JHU/APL Category: Informational D. Mills ISSN: 2070-1721 U. Delaware June 2010 Network Time Protocol Version 4: Autokey Specification Abstract This memo describes the Autokey security model for authenticating servers to clients using the Network Time Protocol (NTP) and public key cryptography. Its design is based on the premise that IPsec schemes cannot be adopted intact, since that would preclude stateless servers and severely compromise timekeeping accuracy. In addition, Public Key Infrastructure (PKI) schemes presume authenticated time values are always available to enforce certificate lifetimes; however, cryptographically verified timestamps require interaction between the timekeeping and authentication functions. This memo includes the Autokey requirements analysis, design principles, and protocol specification. A detailed description of the protocol states, events, and transition functions is included. A prototype of the Autokey design based on this memo has been implemented, tested, and documented in the NTP version 4 (NTPv4) software distribution for the Unix, Windows, and Virtual Memory System (VMS) operating systems at http://www.ntp.org. Status of This Memo This document is not an Internet Standards Track specification; it is published for informational purposes. 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). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc5906. Haberman & Mills Informational [Page 1] RFC 5906 NTPv4 Autokey June 2010 Copyright Notice Copyright (c) 2010 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. 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. Haberman & Mills Informational [Page 2] RFC 5906 NTPv4 Autokey June 2010 Table of Contents 1. Introduction ....................................................4 2. NTP Security Model ..............................................4 3. Approach ........................................................7 4. Autokey Cryptography ............................................8 5. Autokey Protocol Overview ......................................12 6. NTP Secure Groups ..............................................14 7. Identity Schemes ...............................................19 8. Timestamps and Filestamps ......................................20 9. Autokey Operations .............................................22 10. Autokey Protocol Messages .....................................23 10.1. No-Operation .............................................26 10.2. Association Message (ASSOC) ..............................26 10.3. Certificate Message (CERT) ...............................26 10.4. Cookie Message (COOKIE) ..................................27 10.5. Autokey Message (AUTO) ...................................27Show full document text