Cachable OSCORE
draft-amsuess-core-cachable-oscore-00

Document Type Active Internet-Draft (individual)
Authors Christian Amsüss  , Marco Tiloca 
Last updated 2020-07-13
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CoRE                                                           C. Amsüss
Internet-Draft                                                          
Intended status: Experimental                                  M. Tiloca
Expires: 14 January 2021                                         RISE AB
                                                            13 July 2020

                            Cachable OSCORE
                 draft-amsuess-core-cachable-oscore-00

Abstract

   OSCORE group communication can secure CoAP group communication across
   untrusted proxies, but in doing so sidesteps the proxies' caching
   abilities.  This restores cachability of requests by introducing
   consensus requests which any client in a group can send.

Note to Readers

   Discussion of this document takes place on the CORE Working Group
   mailing list (core@ietf.org), which is archived at
   https://mailarchive.ietf.org/arch/browse/core/
   (https://mailarchive.ietf.org/arch/browse/core/).

   Source for this draft and an issue tracker can be found at
   https://gitlab.com/chrysn/core-cachable-oscore/
   (https://gitlab.com/chrysn/core-cachable-oscore/-/tree/master).

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 14 January 2021.

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Copyright Notice

   Copyright (c) 2020 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
     1.1.  Procedural Status . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Simple Cachability using Ticket Requests  . . . . . . . . . .   4
     3.1.  Usefullness . . . . . . . . . . . . . . . . . . . . . . .   5
   4.  Deterministic Requests  . . . . . . . . . . . . . . . . . . .   5
     4.1.  ID-Detail . . . . . . . . . . . . . . . . . . . . . . . .   6
     4.2.  Use of Deterministic Requests . . . . . . . . . . . . . .   6
   5.  Open questions  . . . . . . . . . . . . . . . . . . . . . . .   7
   6.  Unsorted further ideas  . . . . . . . . . . . . . . . . . . .   7
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   With OSCORE group communication, requests and responses can be read
   by other group members can be read by any group member as long as
   pairwise mode is not used.  While this can populate a proxy's cache
   if the proxy is a member of the group, and the proxy can use the
   cache to respond if is recognized by the client as an eligible
   server, untrusted proxies only see opaque uncachable ciphertext.

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   This document introduces cachability in responses in two stages,
   initially building on concepts developed in
   [I-D.tiloca-core-observe-multicast-notifications].  Caching is thus
   enabled for proxies that are not members of the OSCORE group, and are
   unaware of OSCORE in general.  Allowing them to cache requests is
   traded against some request privacy: For clients that participate in
   this scheme, the proxy (and any other party that can read the network
   traffic) can see which clients request the same resource, and how the
   resource's representation changes in size over time.

   As in [I-D.tiloca-core-observe-multicast-notifications], clients and
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