The Token Binding Protocol Version 1.0
draft-ietf-tokbind-protocol-01

The information below is for an old version of the document
Document Type Active Internet-Draft (tokbind WG)
Last updated 2015-05-29
Replaces draft-popov-token-binding
Stream IETF
Intended RFC status Proposed Standard
Formats plain text pdf html bibtex
Stream WG state WG Document
Document shepherd No shepherd assigned
IESG IESG state I-D Exists
Consensus Boilerplate Unknown
Telechat date
Responsible AD (None)
Send notices to (None)
Internet Engineering Task Force                            A. Popov, Ed.
Internet-Draft                                               M. Nystroem
Intended status: Standards Track                         Microsoft Corp.
Expires: November 30, 2015                                    D. Balfanz
                                                              A. Langley
                                                             Google Inc.
                                                            May 29, 2015

                 The Token Binding Protocol Version 1.0
                     draft-ietf-tokbind-protocol-01

Abstract

   This document specifies Version 1.0 of the Token Binding protocol.
   The Token Binding protocol allows client/server applications to
   create long-lived, uniquely identifiable TLS [RFC5246] bindings
   spanning multiple TLS sessions and connections.  Applications are
   then enabled to cryptographically bind security tokens to the TLS
   layer, preventing token export and replay attacks.  To protect
   privacy, the TLS Token Binding identifiers are only transmitted
   encrypted and can be reset by the user at any time.

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 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 November 30, 2015.

Copyright Notice

   Copyright (c) 2015 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

Popov, et al.           Expires November 30, 2015               [Page 1]
Internet-Draft   The Token Binding Protocol Version 1.0         May 2015

   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
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Token Binding Protocol Overview . . . . . . . . . . . . . . .   3
   3.  Token Binding Protocol Message  . . . . . . . . . . . . . . .   4
   4.  Establishing a TLS Token Binding  . . . . . . . . . . . . . .   6
   5.  TLS Token Binding ID Format . . . . . . . . . . . . . . . . .   7
   6.  Security Token Validation . . . . . . . . . . . . . . . . . .   7
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
     8.1.  Security Token Replay . . . . . . . . . . . . . . . . . .   9
     8.2.  Downgrade Attacks . . . . . . . . . . . . . . . . . . . .   9
     8.3.  Privacy Considerations  . . . . . . . . . . . . . . . . .   9
     8.4.  Token Binding Key Sharing Between Applications  . . . . .  10
     8.5.  Triple Handshake Vulnerability in TLS . . . . . . . . . .  10
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   Web services generate various security tokens (e.g.  HTTP cookies,
   OAuth tokens) for web applications to access protected resources.
   Any party in possession of such token gains access to the protected
   resource.  Attackers export bearer tokens from the user's machine,
   present them to web services, and impersonate authenticated users.
   The idea of Token Binding is to prevent such attacks by
   cryptographically binding security tokens to the TLS layer.

   A TLS Token Binding is established by the user agent generating a
   private-public key pair (possibly within a secure hardware module,
   such as TPM) per target server, and proving possession of the private
   key on every TLS connection to the target server.  The proof of
   possession involves signing the tls_unique value [RFC5929] for the
   TLS connection with the private key.  Such TLS Token Binding is
   identified by the corresponding public key.  TLS Token Bindings are
Show full document text