Transport Layer Security (TLS) Extensions: Extension Definitions
RFC 6066

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Internet Engineering Task Force (IETF)                   D. Eastlake 3rd
Request for Comments: 6066                                        Huawei
Obsoletes: 4366                                             January 2011
Category: Standards Track
ISSN: 2070-1721

    Transport Layer Security (TLS) Extensions: Extension Definitions

Abstract

   This document provides specifications for existing TLS extensions.
   It is a companion document for RFC 5246, "The Transport Layer
   Security (TLS) Protocol Version 1.2".  The extensions specified are
   server_name, max_fragment_length, client_certificate_url,
   trusted_ca_keys, truncated_hmac, and status_request.

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/rfc6066.

Copyright Notice

   Copyright (c) 2011 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
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   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.

Eastlake                     Standards Track                    [Page 1]
RFC 6066                TLS Extension Definitions           January 2011

   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
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   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.

Table of Contents

   1. Introduction ....................................................3
      1.1. Specific Extensions Covered ................................3
      1.2. Conventions Used in This Document ..........................5
   2. Extensions to the Handshake Protocol ............................5
   3. Server Name Indication ..........................................6
   4. Maximum Fragment Length Negotiation .............................8
   5. Client Certificate URLs .........................................9
   6. Trusted CA Indication ..........................................12
   7. Truncated HMAC .................................................13
   8. Certificate Status Request .....................................14
   9. Error Alerts ...................................................16
   10. IANA Considerations ...........................................17
      10.1. pkipath MIME Type Registration ...........................17
      10.2. Reference for TLS Alerts, TLS HandshakeTypes, and
            ExtensionTypes ...........................................19
   11. Security Considerations .......................................19
      11.1. Security Considerations for server_name ..................19
      11.2. Security Considerations for max_fragment_length ..........20
      11.3. Security Considerations for client_certificate_url .......20
      11.4. Security Considerations for trusted_ca_keys ..............21
      11.5. Security Considerations for truncated_hmac ...............21
      11.6. Security Considerations for status_request ...............22
   12. Normative References ..........................................22
   13. Informative References ........................................23
   Appendix A. Changes from RFC 4366 .................................24
   Appendix B. Acknowledgements ......................................25

Eastlake                     Standards Track                    [Page 2]
RFC 6066                TLS Extension Definitions           January 2011

1.  Introduction

   The Transport Layer Security (TLS) Protocol Version 1.2 is specified
   in [RFC5246].  That specification includes the framework for