Datagram Transport Layer Security Version 1.2
RFC 6347

Internet Engineering Task Force (IETF)                       E. Rescorla
Request for Comments: 6347                                    RTFM, Inc.
Obsoletes: 4347                                              N. Modadugu
Category: Standards Track                                   Google, Inc.
ISSN: 2070-1721                                             January 2012

             Datagram Transport Layer Security Version 1.2

Abstract

   This document specifies version 1.2 of the Datagram Transport Layer
   Security (DTLS) protocol.  The DTLS protocol provides communications
   privacy for datagram protocols.  The protocol allows client/server
   applications to communicate in a way that is designed to prevent
   eavesdropping, tampering, or message forgery.  The DTLS protocol is
   based on the Transport Layer Security (TLS) protocol and provides
   equivalent security guarantees.  Datagram semantics of the underlying
   transport are preserved by the DTLS protocol.  This document updates
   DTLS 1.0 to work with TLS version 1.2.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6347.

Rescorla & Modadugu          Standards Track                    [Page 1]
RFC 6347                          DTLS                      January 2012

Copyright Notice

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   document authors.  All rights reserved.

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   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
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   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
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   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Rescorla & Modadugu          Standards Track                    [Page 2]
RFC 6347                          DTLS                      January 2012

Table of Contents

   1. Introduction ....................................................4
      1.1. Requirements Terminology ...................................5
   2. Usage Model .....................................................5
   3. Overview of DTLS ................................................5
      3.1. Loss-Insensitive Messaging .................................6
      3.2. Providing Reliability for Handshake ........................6
           3.2.1. Packet Loss .........................................6
           3.2.2. Reordering ..........................................7
           3.2.3. Message Size ........................................7
      3.3. Replay Detection ...........................................7
   4. Differences from TLS ............................................7
      4.1. Record Layer ...............................................8
           4.1.1. Transport Layer Mapping ............................10
                  4.1.1.1. PMTU Issues ...............................10
           4.1.2. Record Payload Protection ..........................12
                  4.1.2.1. MAC .......................................12
                  4.1.2.2. Null or Standard Stream Cipher ............13
                  4.1.2.3. Block Cipher ..............................13
                  4.1.2.4. AEAD Ciphers ..............................13
                  4.1.2.5. New Cipher Suites .........................13