Delegated Credentials for TLS
draft-ietf-tls-subcerts-00

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Network Working Group                                          R. Barnes
Internet-Draft                                                   Mozilla
Intended status: Standards Track                              S. Iyengar
Expires: May 3, 2018                                            Facebook
                                                             N. Sullivan
                                                              Cloudflare
                                                             E. Rescorla
                                                              RTFM, Inc.
                                                        October 30, 2017

                     Delegated Credentials for TLS
                       draft-ietf-tls-subcerts-00

Abstract

   The organizational separation between the operator of a TLS server
   and the certificate authority that provides it credentials can cause
   problems, for example when it comes to reducing the lifetime of
   certificates or supporting new cryptographic algorithms.  This
   document describes a mechanism to allow TLS server operators to
   create their own credential delegations without breaking
   compatibility with clients that do not support this specification.

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 May 3, 2018.

Copyright Notice

   Copyright (c) 2017 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

Barnes, et al.             Expires May 3, 2018                  [Page 1]
Internet-Draft        Delegated Credentials for TLS         October 2017

   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Solution Overview . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Rationale . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.2.  Related Work  . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Client and Server behavior  . . . . . . . . . . . . . . . . .   6
   4.  Delegated Credentials . . . . . . . . . . . . . . . . . . . .   7
     4.1.  Certificate Requirements  . . . . . . . . . . . . . . . .   8
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
     6.1.  Security of delegated private key . . . . . . . . . . . .   9
     6.2.  Revocation of delegated credentials . . . . . . . . . . .   9
     6.3.  Privacy considerations  . . . . . . . . . . . . . . . . .   9
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   Typically, a TLS server uses a certificate provided by some entity
   other than the operator of the server (a "Certification Authority" or
   CA) [RFC5246] [RFC5280].  This organizational separation makes the
   TLS server operator dependent on the CA for some aspects of its
   operations, for example:

   o  Whenever the server operator wants to deploy a new certificate, it
      has to interact with the CA.

   o  The server operator can only use TLS authentication schemes for
      which the CA will issue credentials.

   These dependencies cause problems in practice.  Server operators
   often want to create short-lived certificates for servers in low-
   trust zones such as CDNs or remote data centers.  This allows server
   operators to limit the exposure of keys in cases that they do not
   realize a compromise has occurred.  The risk inherent in cross-
   organizational transactions makes it operationally infeasible to rely