Transport Layer Security (TLS) Cached Information Extension
draft-ietf-tls-cached-info-22

Document Type Active Internet-Draft (tls WG)
Last updated 2016-01-26
Replaces draft-santesson-tls-certcache
Stream IETF
Intended RFC status Proposed Standard
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Stream WG state Submitted to IESG for Publication
Document shepherd J. Salowey
Shepherd write-up Show (last changed 2015-11-02)
IESG IESG state Approved-announcement to be sent::Point Raised - writeup needed
Consensus Yes
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Responsible AD Stephen Farrell
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IANA IANA review state Version Changed - Review Needed
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TLS                                                         S. Santesson
Internet-Draft                                           3xA Security AB
Intended status: Standards Track                           H. Tschofenig
Expires: July 29, 2016                                          ARM Ltd.
                                                        January 26, 2016

      Transport Layer Security (TLS) Cached Information Extension
                   draft-ietf-tls-cached-info-22.txt

Abstract

   Transport Layer Security (TLS) handshakes often include fairly static
   information, such as the server certificate and a list of trusted
   certification authorities (CAs).  This information can be of
   considerable size, particularly if the server certificate is bundled
   with a complete certificate chain (i.e., the certificates of
   intermediate CAs up to the root CA).

   This document defines an extension that allows a TLS client to inform
   a server of cached information, allowing the server to omit already
   available information.

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
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   Drafts is at http://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 July 29, 2016.

Copyright Notice

   Copyright (c) 2016 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
   (http://trustee.ietf.org/license-info) in effect on the date of

Santesson & Tschofenig    Expires July 29, 2016                 [Page 1]
Internet-Draft      TLS Cached Information Extension        January 2016

   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.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Cached Information Extension  . . . . . . . . . . . . . . . .   3
   4.  Exchange Specification  . . . . . . . . . . . . . . . . . . .   5
     4.1.  Server Certificate Message  . . . . . . . . . . . . . . .   5
     4.2.  CertificateRequest Message  . . . . . . . . . . . . . . .   6
   5.  Fingerprint Calculation . . . . . . . . . . . . . . . . . . .   7
   6.  Example . . . . . . . . . . . . . . . . . . . . . . . . . . .   8
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
     8.1.  New Entry to the TLS ExtensionType Registry . . . . . . .  10
     8.2.  New Registry for CachedInformationType  . . . . . . . . .  10
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  11
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  11
     10.2.  Informative References . . . . . . . . . . . . . . . . .  12
   Appendix A.  Example  . . . . . . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  18

1.  Introduction

   Reducing the amount of information exchanged during a Transport Layer
   Security handshake to a minimum helps to improve performance in
   environments where devices are connected to a network with a low
   bandwidth, and lossy radio technology.  With Internet of Things such
   environments exist, for example, when devices use IEEE 802.15.4 or
   Bluetooth Smart.  For more information about the challenges with
   smart object deployments please see [RFC6574].

   This specification defines a TLS extension that allows a client and a
   server to exclude transmission information cached in an earlier TLS
   handshake.

   A typical example exchange may therefore look as follows.  First, the
   client and the server executes the full TLS handshake.  The client
   then caches the certificate provided by the server.  When the TLS
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