Beehive moderation

There is a simple idea for decentralized moderation without hierarchies. You allow anyone to remove any other member like is allowed in Delta Chat already, but the member who removes someone has to leave as well.

This disincentivizes removing random members. If the member removes actual spammer or troll, the group will add such member back in later. If a troll removes random member without a reason, the group will add member back, but not the troll.

As far as I know the idea originates in the paper Suicide for the Common Good: a New Strategy for Credential Revocation in Self-Organizing Systems (2006). You can read the PDF at https://cs.wellesley.edu/~tmoore/OSR-suicide.pdf

There are however some problems for practical implementation of this:

  1. An attacker can add as many puppet profiles as already in the group first,
    then completely destroy the group by removing everyone.
    This is referred in the paper as Sybil and replication attacks.
    A solution may be to disallow new members adding members
    until they are in a group for 30 days,
    some voucher/ticket system or voting
    (which may be better than just introducing voting for removals
    because it allows to quickly remove members in case of abuse).
  2. The paper implicitly assumes the existence of broadcast channel.
    An attacker may send a removing Alice
    to half of the group and a message removing Bob to half of the group.
    Then the group will have to figure out whether Alice or Bob should be removed,
    ideally invalidating both removals and only removing the attacker.

This idea had some popularity in MANET research and there are many related papers continuing this theme at Google Scholar, for example: The fable of the bees: incentivizing robust revocation decision making in ad hoc networks (2009) (The fable of the bees: Incentivizing robust revocation decision making in ad hoc networks for CCS 2009 - IBM Research) with a PDF available at https://web.archive.org/web/20170809071452id_/http://amnesia.gtisc.gatech.edu/~moyix/CCS_09/docs/p291.pdf

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