Opportunistic Security for HTTP
draft-ietf-httpbis-http2-encryption-01

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Document Type Active Internet-Draft (httpbis WG)
Last updated 2015-02-10 (latest revision 2014-12-15)
Replaces draft-nottingham-http2-encryption
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Intended RFC status Experimental
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Document shepherd Mark Nottingham
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Send notices to "Mark Nottingham" <mnot@mnot.net>
HTTPbis Working Group                                      M. Nottingham
Internet-Draft
Intended status: Experimental                                 M. Thomson
Expires: June 18, 2015                                           Mozilla
                                                       December 15, 2014

                    Opportunistic Security for HTTP
                 draft-ietf-httpbis-http2-encryption-01

Abstract

   This document describes how "http" URIs can be accessed using
   Transport Layer Security (TLS) to mitigate pervasive monitoring
   attacks.

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 June 18, 2015.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Goals and Non-Goals . . . . . . . . . . . . . . . . . . .   3
     1.2.  Notational Conventions  . . . . . . . . . . . . . . . . .   3
   2.  Using HTTP URIs over TLS  . . . . . . . . . . . . . . . . . .   3
   3.  Server Authentication . . . . . . . . . . . . . . . . . . . .   4
   4.  Interaction with "https" URIs . . . . . . . . . . . . . . . .   4
   5.  Requiring Use of TLS  . . . . . . . . . . . . . . . . . . . .   5
     5.1.  The HTTP-TLS Header Field . . . . . . . . . . . . . . . .   5
     5.2.  Operational Considerations  . . . . . . . . . . . . . . .   6
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
     6.1.  Security Indicators . . . . . . . . . . . . . . . . . . .   7
     6.2.  Downgrade Attacks . . . . . . . . . . . . . . . . . . . .   7
     6.3.  Privacy Considerations  . . . . . . . . . . . . . . . . .   7
     6.4.  Confusion Regarding Request Scheme  . . . . . . . . . . .   8
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Appendix A.  Acknowledgements . . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   This document describes a use of HTTP Alternative Services
   [I-D.ietf-httpbis-alt-svc] to decouple the URI scheme from the use
   and configuration of underlying encryption, allowing a "http" URI to
   be accessed using TLS [RFC5246] opportunistically.

   Currently, "https" URIs require acquiring and configuring a valid
   certificate, which means that some deployments find supporting TLS
   difficult.  Therefore, this document describes a usage model whereby
   sites can serve "http" URIs over TLS without being required to
   support strong server authentication.

   Opportunistic Security [I-D.dukhovni-opportunistic-security] does not
   provide the same guarantees as using TLS with "https" URIs; it is
   vulnerable to active attacks, and does not change the security
   context of the connection.  Normally, users will not be able to tell
   that it is in use (i.e., there will be no "lock icon").

   By its nature, this technique is vulnerable to active attacks.  A
   mechanism for partially mitigating them is described in Section 5.
   It does not offer the same level of protection as afforded to "https"
   URIs, but increases the likelihood that an active attack be detected.

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1.1.  Goals and Non-Goals

   The immediate goal is to make the use of HTTP more robust in the face
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