TLS Certificate Compression
draft-ietf-tls-certificate-compression-04

Document Type Active Internet-Draft (tls WG)
Last updated 2018-10-03
Replaces draft-ghedini-tls-certificate-compression
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TLS                                                           A. Ghedini
Internet-Draft                                          Cloudflare, Inc.
Intended status: Standards Track                             V. Vasiliev
Expires: April 6, 2019                                            Google
                                                        October 03, 2018

                      TLS Certificate Compression
               draft-ietf-tls-certificate-compression-04

Abstract

   In TLS handshakes, certificate chains often take up the majority of
   the bytes transmitted.

   This document describes how certificate chains can be compressed to
   reduce the amount of data transmitted and avoid some round trips.

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 6, 2019.

Copyright Notice

   Copyright (c) 2018 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
   (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

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Notational Conventions  . . . . . . . . . . . . . . . . . . .   2
   3.  Negotiating Certificate Compression . . . . . . . . . . . . .   2
   4.  Compressed Certificate Message  . . . . . . . . . . . . . . .   3
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  Middlebox Compatibility . . . . . . . . . . . . . . . . . . .   5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
     7.1.  Update of the TLS ExtensionType Registry  . . . . . . . .   5
     7.2.  Update of the TLS HandshakeType Registry  . . . . . . . .   5
     7.3.  Registry for Compression Algorithms . . . . . . . . . . .   5
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   6
   Appendix A.  Acknowledgements . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   In order to reduce latency and improve performance it can be useful
   to reduce the amount of data exchanged during a TLS handshake.

   [RFC7924] describes a mechanism that allows a client and a server to
   avoid transmitting certificates already shared in an earlier
   handshake, but it doesn't help when the client connects to a server
   for the first time and doesn't already have knowledge of the server's
   certificate chain.

   This document describes a mechanism that would allow certificates to
   be compressed during full handshakes.

2.  Notational Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  Negotiating Certificate Compression

   This extension is only supported with TLS 1.3 and newer; if TLS 1.2
   or earlier is negotiated, the peers MUST ignore this extension.

   This document defines a new extension type
   (compress_certificate(27)), which can be used to signal the supported

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   compression formats for the Certificate message to the peer.
   Whenever it is sent by the client as a ClientHello message extension
   ([RFC8446], Section 4.1.2), it indicates the support for compressed
   server certificates.  Whenever it is sent by the server as a
   CertificateRequest extension ([RFC8446], Section 4.3.2), it indicates
   the support for compressed client certificates.
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