Using the Network Time Security Specification to Secure the Network Time Protocol
draft-ietf-ntp-using-nts-for-ntp-00
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NTP Working Group D. Sibold
Internet-Draft PTB
Intended status: Standards Track S. Roettger
Expires: September 7, 2015 Google Inc
K. Teichel
PTB
March 06, 2015
Using the Network Time Security Specification to Secure the Network Time
Protocol
draft-ietf-ntp-using-nts-for-ntp-00.txt
Abstract
This document describes how to use the measures described in the
Network Time Security (NTS) specification to secure time
synchronization with servers using the Network Time Protocol (NTP).
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
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."
This Internet-Draft will expire on September 7, 2015.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
Sibold, et al. Expires September 7, 2015 [Page 1]
Internet-Draft NTS4NTP March 2015
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
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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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Objectives . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Terms and Abbreviations . . . . . . . . . . . . . . . . . . . 4
4. Overview of NTS-Secured NTP . . . . . . . . . . . . . . . . . 4
4.1. Symmetric and Client/Server Mode . . . . . . . . . . . . 4
4.2. Broadcast Mode . . . . . . . . . . . . . . . . . . . . . 4
5. Protocol Sequence . . . . . . . . . . . . . . . . . . . . . . 4
5.1. The Client . . . . . . . . . . . . . . . . . . . . . . . 4
5.1.1. The Client in Unicast Mode . . . . . . . . . . . . . 4
5.1.2. The Client in Broadcast Mode . . . . . . . . . . . . 6
5.2. The Server . . . . . . . . . . . . . . . . . . . . . . . 8
5.2.1. The Server in Unicast Mode . . . . . . . . . . . . . 8
5.2.2. The Server in Broadcast Mode . . . . . . . . . . . . 9
6. Implementation Notes: ASN.1 Structures and Use of the CMS . . 9
6.1. Unicast Messages . . . . . . . . . . . . . . . . . . . . 9
6.1.1. Association Messages . . . . . . . . . . . . . . . . 9
6.1.2. Cookie Messages . . . . . . . . . . . . . . . . . . . 10
6.1.3. Time Synchronization Messages . . . . . . . . . . . . 10
6.2. Broadcast Messages . . . . . . . . . . . . . . . . . . . 11
6.2.1. Broadcast Parameter Messages . . . . . . . . . . . . 11
6.2.2. Broadcast Time Synchronization Message . . . . . . . 11
6.2.3. Broadcast Keycheck . . . . . . . . . . . . . . . . . 11
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12
7.1. Usage of NTP Pools . . . . . . . . . . . . . . . . . . . 12
7.2. Server Seed Lifetime . . . . . . . . . . . . . . . . . . 12
7.3. Supported Hash Algorithms . . . . . . . . . . . . . . . . 12
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
9.1. Normative References . . . . . . . . . . . . . . . . . . 12
9.2. Informative References . . . . . . . . . . . . . . . . . 13
Appendix A. Flow Diagrams of Client Behaviour . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
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