Towards a CAP Theorem for Censorship Circumvention
draft-cfm-circumvention-cap-theorem-01

Network Working Group                                           C. Myers
Internet-Draft                                                ARTICLE 19
Intended status: Informational                          26 November 2023
Expires: 29 May 2024

           Towards a CAP Theorem for Censorship Circumvention
                 draft-cfm-circumvention-cap-theorem-01

Abstract

   This Internet-Draft is a submission to the IAB Workshop on Barriers
   to Internet Access of Services [biasws].

About This Document

   This note is to be removed before publishing as an RFC.

   Status information for this document may be found at
   https://datatracker.ietf.org/doc/draft-cfm-circumvention-cap-
   theorem/.

   Source for this draft and an issue tracker can be found at
   https://github.com/cfm/draft-cfm-circumvention-cap-theorem.

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   Copyright (c) 2023 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Table of Contents

   1.  Research proposal . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Informative References  . . . . . . . . . . . . . . . . . . .   2
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   3

1.  Research proposal

   Between June 2022 and April 2023 [tor-status], the Tor network was
   the target of a sustained distributed denial-of-service (DDoS)
   attack, apparently targeting the relays and directory servers that
   coordinate introductions to Tor hidden services [tor-relays-2022-07]
   [tor-relays-2022-10].  This attack impeded the performance and
   threatened the security of the Tor network for all users.  It
   especially obstructed Web sites and services that had gone out of
   their way to be accessible to Tor users via Tor hidden services,
   which usually improve the performance of the Tor network by bypassing
   the "exit nodes" that interface with the clearnet Internet.

   Although the origins and motivations of this attack remain unknown,
   it is a useful case study in the D/DoS vulnerability of overlay
   networks such as Tor, which users may seek out to protect their
   anonymity, circumvent censorship, or both.  The CAP theorem
   [cap-theorem] is instructive: like a database, a censorship-
   circumvention system is useful to the extent that it is:

   1.  *consistent:* returns accurate and current data;

   2.  *available:* returns data at all; and

   3.  *partition-tolerant*: routes around failures, which by definition
       include active censorship.  In this case, they also include
       active _attacks_ on circumvention infrastructure that lessen its
       overall availability, whether or not intended as an act of
       censorship.

   For the workshop, I propose to explore further whether formalisms
   such as the CAP theorem are useful models and/or measures for the
   utility and resilience of a censorship-circumvention system such as
   Tor.

2.  Informative References

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Internet-Draft  Towards a CAP Theorem for Censorship Cir   November 2023

   [biasws]   Internet Architecture Board, "Workshop on Barriers to
              Internet Access of Services", 20 September 2023,
              <https://datatracker.ietf.org/group/biasws/about/>.

   [cap-theorem]
              "CAP theorem", n.d.,
              <https://en.wikipedia.org/wiki/CAP_theorem>.

   [tor-relays-2022-07]
              Dingledine, R., "We're trying out guard-n-primary-guards-
              to-use=2", 6 July 2022,
              <https://lists.torproject.org/pipermail/tor-
              relays/2022-July/020686.html>.

   [tor-relays-2022-10]
              Koppen, G., "DoS attacks -- status update", 28 October
              2022, <https://lists.torproject.org/pipermail/tor-
              relays/2022-October/020858.html>.

   [tor-status]
              Tor Project, "Network DDoS", 9 June 2022,
              <https://status.torproject.org/issues/2022-06-09-network-
              ddos/>.

Author's Address

   Cory Myers
   ARTICLE 19
   Email: cfm@acm.org

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