Network Time Security
draft-ietf-ntp-network-time-security-01
NTP Working Group D. Sibold
Internet-Draft PTB
Intended status: Standards Track S. Roettger
Expires: April 21, 2014 TU-BS
K. Teichel
PTB
October 18, 2013
Network Time Security
draft-ietf-ntp-network-time-security-01.txt
Abstract
This document describes the Network Time Security (NTS) protocol that
enables secure authentication of time servers using Network Time
Protocol (NTP) or Precision Time Protocol (PTP). Its design
considers the special requirements of precise timekeeping, which are
described in Security Requirements of Time Protocols in Packet
Switched Network [I-D.ietf-tictoc-security-requirements].
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
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This Internet-Draft will expire on April 21, 2014.
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
Sibold, et al. Expires April 21, 2014 [Page 1]
Internet-Draft NTS October 2013
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Security Threats . . . . . . . . . . . . . . . . . . . . . . 3
3. Objectives . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Terms and Abbreviations . . . . . . . . . . . . . . . . . . . 4
5. NTS Overview . . . . . . . . . . . . . . . . . . . . . . . . 4
5.1. Symmetric and Client/Server Mode . . . . . . . . . . . . 4
5.2. Broadcast Mode . . . . . . . . . . . . . . . . . . . . . 5
6. Protocol Sequence . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Association Message . . . . . . . . . . . . . . . . . . . 5
6.2. Certificate Message . . . . . . . . . . . . . . . . . . . 5
6.3. Cookie Message . . . . . . . . . . . . . . . . . . . . . 6
6.4. Broadcast Parameter Message . . . . . . . . . . . . . . . 6
6.5. Time Request Message . . . . . . . . . . . . . . . . . . 7
6.6. Broadcast Message . . . . . . . . . . . . . . . . . . . . 7
6.7. Server Seed Refresh . . . . . . . . . . . . . . . . . . . 7
7. Hash Algorithms and MAC Generation . . . . . . . . . . . . . 8
7.1. Hash Algorithms . . . . . . . . . . . . . . . . . . . . . 8
7.2. MAC Calculation . . . . . . . . . . . . . . . . . . . . . 8
8. Server Seed Considerations . . . . . . . . . . . . . . . . . 8
8.1. Server Seed Algorithm . . . . . . . . . . . . . . . . . . 9
8.2. Server Seed Live Time . . . . . . . . . . . . . . . . . . 9
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
10. Security Considerations . . . . . . . . . . . . . . . . . . . 9
10.1. Initial Verification of the Server Certificates . . . . 9
10.2. Revocation of Server Certificates . . . . . . . . . . . 9
10.3. Usage of NTP Pools . . . . . . . . . . . . . . . . . . . 10
10.4. Denial-of-Service in Broadcast Mode . . . . . . . . . . 10
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
12.1. Normative References . . . . . . . . . . . . . . . . . . 10
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