A Secure Selection and Filtering Mechanism for the Network Time Protocol Version 4
draft-schiff-ntp-chronos-01

Document Type Active Internet-Draft (individual)
Last updated 2018-10-21
Stream (None)
Intended RFC status (None)
Formats plain text xml pdf html bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
Network Working Group                                        N. R.Schiff
Internet-Draft                                                  D. Dolev
Intended status: Informational            Hebrew University of Jerusalem
Expires: April 24, 2019                                       T. Mizrahi
                                        Huawei Network.IO Innovation Lab
                                                             M. Schapira
                                          Hebrew University of Jerusalem
                                                        October 21, 2018

A Secure Selection and Filtering Mechanism for the Network Time Protocol
                               Version 4
                      draft-schiff-ntp-chronos-01

Abstract

   The Network Time Protocol version 4 (NTPv4) defines the peer process,
   the clock filter algorithm, the system process and the clock
   description algorithm.  The clock filter algorithm and the system
   process, as defined in RFC 5905, are the mechanism according to which
   an NTP client chooses the NTP servers it synchronized with.  This
   document specifies an alternative set of client mechanisms, named
   Chronos, that is backward compatible with NTPv4, and offers an
   improved level of security against time shifting attacks.

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 https://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 April 24, 2019.

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

R.Schiff, et al.         Expires April 24, 2019                 [Page 1]
Internet-Draft         NTP Extention with Chronos           October 2018

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions Used in This Document . . . . . . . . . . . . . .   3
     2.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Terms and Abbreviations . . . . . . . . . . . . . . . . .   3
     2.3.  Notations . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Extension for NTP Selection Process . . . . . . . . . . . . .   4
     3.1.  Peer calibration Process  . . . . . . . . . . . . . . . .   4
     3.2.  Chronos Selection Process . . . . . . . . . . . . . . . .   4
   4.  Chronos Pseudocode  . . . . . . . . . . . . . . . . . . . . .   5
   5.  Precision Vs. Security  . . . . . . . . . . . . . . . . . . .   5
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   According to RFC 5905 [RFC5905], the NTP servers used for updating
   the client's time are chosen by the clock filter algorithm and the
   system process.  However, this method may be vulnerable to time
   shifting attacks, in which the attacker's goal is to shift the local
   time of an NTP client.  Time shifting attacks on NTP are possible
   even if all NTP communications are encrypted and authenticated.  This
   document introduces an improved system process with a secure
   algorithm called Chronos.  Chronos is backwards compatible with
   NTPv4, as an NTP client that runs Chronos is interoperable with
   [RFC5905]-compatible NTPv4 servers.

   Chronos achieves accurate synchronization even in the presence of
   powerful attackers who are in direct control of a large number of NTP
   servers.  Chronos leverages ideas from distributed computing
Show full document text