The Datagram Transport Layer Security (DTLS) Protocol Version 1.3
draft-ietf-tls-dtls13-01

Document Type Active Internet-Draft (tls WG)
Last updated 2017-07-11
Replaces draft-rescorla-tls-dtls13
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TLS                                                          E. Rescorla
Internet-Draft                                                RTFM, Inc.
Obsoletes: 6347 (if approved)                              H. Tschofenig
Intended status: Standards Track                             ARM Limited
Expires: January 8, 2018                                     N. Modadugu
                                                            Google, Inc.
                                                           July 07, 2017

   The Datagram Transport Layer Security (DTLS) Protocol Version 1.3
                        draft-ietf-tls-dtls13-01

Abstract

   This document specifies Version 1.3 of the Datagram Transport Layer
   Security (DTLS) protocol.  DTLS 1.3 allows client/server applications
   to communicate over the Internet in a way that is designed to prevent
   eavesdropping, tampering, and message forgery.

   The DTLS 1.3 protocol is intentionally based on the Transport Layer
   Security (TLS) 1.3 protocol and provides equivalent security
   guarantees.  Datagram semantics of the underlying transport are
   preserved by the DTLS protocol.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on January 8, 2018.

Copyright Notice

   Copyright (c) 2017 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

Rescorla, et al.         Expires January 8, 2018                [Page 1]
Internet-Draft                  DTLS 1.3                       July 2017

   (http://trustee.ietf.org/license-info) in effect on the date of
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   than English.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Conventions and Terminology . . . . . . . . . . . . . . . . .   4
   3.  DTLS Design Rational and Overview . . . . . . . . . . . . . .   5
     3.1.  Packet Loss . . . . . . . . . . . . . . . . . . . . . . .   6
       3.1.1.  Reordering  . . . . . . . . . . . . . . . . . . . . .   6
       3.1.2.  Message Size  . . . . . . . . . . . . . . . . . . . .   7
     3.2.  Replay Detection  . . . . . . . . . . . . . . . . . . . .   7
   4.  The DTLS Record Layer . . . . . . . . . . . . . . . . . . . .   7
     4.1.  Sequence Number Handling  . . . . . . . . . . . . . . . .   8
     4.2.  Transport Layer Mapping . . . . . . . . . . . . . . . . .   9
     4.3.  PMTU Issues . . . . . . . . . . . . . . . . . . . . . . .  10
     4.4.  Record Payload Protection . . . . . . . . . . . . . . . .  11
       4.4.1.  Anti-Replay . . . . . . . . . . . . . . . . . . . . .  11
       4.4.2.  Handling Invalid Records  . . . . . . . . . . . . . .  12
   5.  The DTLS Handshake Protocol . . . . . . . . . . . . . . . . .  12
     5.1.  Denial-of-Service Countermeasures . . . . . . . . . . . .  13
     5.2.  DTLS Handshake Message Format . . . . . . . . . . . . . .  16
     5.3.  ClientHello Message . . . . . . . . . . . . . . . . . . .  18
     5.4.  Handshake Message Fragmentation and Reassembly  . . . . .  19
     5.5.  DTLS Handshake Flights  . . . . . . . . . . . . . . . . .  20
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