Handling Large Certificates and Long Certificate Chains in EAP-TLS
draft-ms-emu-eaptlscert-01

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 00
• 01

Network Working Group                                           M. Sethi
Internet-Draft                                               J. Mattsson
Intended status: Informational                                  Ericsson
Expires: April 25, 2019                                 October 22, 2018

   Handling Large Certificates and Long Certificate Chains in EAP-TLS
                       draft-ms-emu-eaptlscert-01

Abstract

   Extensible Authentication Protocol (EAP) provides support for
   multiple authentication methods.  EAP-Transport Layer Security (EAP-
   TLS) provides means for key derivation and strong mutual
   authentication with certificates.  However, certificates can often be
   relatively large in size.  The certificate chain to the root-of-trust
   can also be long when multiple intermediate Certification Authorities
   (CAs) are involved.  This implies that EAP-TLS authentication needs
   to be fragmented into many smaller packets for transportation over
   the lower-layer.  Such fragmentation can not only negatively affect
   the latency, but also results in implementation challenges.  For
   example, many authenticator (access point) implementations will drop
   an EAP session if it hasn't finished after 40 - 50 packets.  This can
   result in failed authentication even when the two communicating
   parties have the correct credentials for mutual authentication.
   Moreover, there are no mechanisms available to easily recover from
   such situations.  This memo looks at the problem in detail and
   discusses the solutions available to overcome these deployment
   challenges.

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 25, 2019.

Sethi & Mattsson         Expires April 25, 2019                 [Page 1]
Internet-Draft           Certificates in EAP-TLS            October 2018

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
   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.  Experience with Deployments . . . . . . . . . . . . . . . . .   3
   4.  Handling of Large Certificates and Long Certificate Chains  .   4
     4.1.  Updating Certificates . . . . . . . . . . . . . . . . . .   4
     4.2.  Updating Code . . . . . . . . . . . . . . . . . . . . . .   5
     4.3.  Guidelines for certificates . . . . . . . . . . . . . . .   6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   EAP-TLS is widely deployed and often used for network access
   authentication of requesting peers.  EAP-TLS provides strong mutual
   authentication with certificates.  However, certificates can be large
   and certificate chains can often be long.  This implies that EAP-TLS
   authentication needs to be fragmented into many smaller packets for
   transportation over the lower-layer.  Such fragmentation can not only
   negatively affect the latency, but also results in implementation
   challenges.  For example, many authenticator (access point)
   implementations will drop an EAP session if it hasn't finished after
   40-50 packets.  This has led to a situation where a client and server
   cannot authenticate each other even though both the sides have valid