Using the Network Time Security Specification to Secure the Network Time Protocol
draft-ietf-ntp-using-nts-for-ntp-00
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
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provisions of BCP 78 and BCP 79.
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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
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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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