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Create a diagram that explains how bridges work

In support of activity 1.2 in project 163, this will be one of three illustrated diagrams to be used as an aid for trainings and usability testing to explain the concept of bridges.

This ticket will serve to track the process of concepting, iterating, and feedback of the diagram as it evolves.

Reference points for how The Tor Project currently describes bridges:

  • tb manual
    • Most Pluggable Transports, such as obfs4, rely on the use of "bridge" relays
    • unlike ordinary relays, however, they are not listed publicly, so an adversary cannot identify them easily
    • Using bridges in combination with pluggable transports helps to conceal the fact that you are using Tor
  • support->censorship
    • Bridge relays are Tor relays that are not listed in the public Tor directory.
    • ISPs or governments trying to block access to the Tor network can't simply block all bridges.
    • Bridges are useful for Tor users under oppressive regimes, and for people who want an extra layer of security because they're worried somebody will recognize that they are contacting a public Tor relay IP address.
    • A bridge is just a normal relay with a slightly different configuration.
  • understanding how tor works slide deck
    • A bridge provides an alternative way to connect to the Tor network. It’s basically a Tor entry relay, but its IP address is not listed on the public directory (the Tor Metrics portal). This makes it harder for Internet Service Providers (ISPs) and governments to block access to the bridge.
    • What’s the use of bridges? Bridges are an anti-censorship feature and we recommend users to connect through a bridge rather than a regular entry relay when Tor is blocked in a user’s country or region.
    • Most bridges add an additional layer of masking called: Pluggable Transports. Pluggable Transports disguise a bridges’ Tor traffic by making it look like a regular connection rather than a Tor connection, adding another layer of obfuscation.
  • bypassing censorship of tor with bridges
    • Tor Browser and other Tor apps include circumvention features for getting around the blocking of Tor; these are called bridges.

Questions:

  • Will the complexity of this concept require words/explanations, or will an illustration without be sufficient enough to accompany other materials?
  • What is the level of technical understanding users might have when referencing this diagram?
  • What is the most fundamental concept that needs to be demonstrated?
  • Any existing diagrams or visuals we are referencing?
  • On the spectrum of abstract to literal, where does this diagram fall?
  • Do we need to communicate any aspect of geography/global reference like we do in the onion routing diagram?

Estimation:

  • Complexity: large (6 days)
  • Uncertainty: high (2)
  • Total: 6 days (expected) – 12 days (worst case)
Edited by nicob