Minimal anti-collusion infrastructure

Applications
2

So just after T_{start} the first user (user_0) is able to publish their vote and get bribed because it is impossible that she created an older transaction to changed her key. However I understnad the arugment as that this user can still after the fact update their vote again and there is no way for them to prove they did not do this.

However if user_0 can add the first two actions to the list then can

  1. user_0 Make their vote
  2. user_0 Update their public key to 0x0 (One where no public key exists)

So now user_0 can sell their vote. As the current state for the briber is

  1. user_0 vote
  2. user_0 invalidate key

If user_1 wants to sell her vote she can also do it by voting and burning her key. The current state for the briber becomes after user_0 shares her key with briber.

  1. user_0 vote
  2. user_0 invalidate key
  3. user_1 vote
  4. user_1 invalidate key

Even are honest voters interacting with the system the bribery can continue Imagine that user_2 takes an action and does not publish it. Our current briber state becomes

  1. user_0 vote
  2. user_0 invalidate key
  3. user_1 vote
  4. user_1 invalidate key
  5. ???

So if all the users from user_3 to user_4 wants to see their vote they cannot right because we are not sure that that user did not invalidate their key at step 5. But what we can do is have them all vote and invalidate in series and then publish the data afterwards. The briber current state is

  1. user_0 vote
  2. user_0 invalidate key
  3. user_1 vote
  4. user_1 invalidate key
  5. ???
  6. user_3 vote
  7. user_3 invalidate key
  8. user_4 vote
  9. user_4 invalidate key

Now we don’t know if user_4 or user_5 invalided their key. So the argument says we cannot bribe them. But we can bribe both of them half the amount we bribed user_0 and be sure that we paid and bought one vote. Because we know for one of them did vote the way that we wanted them to.

This think this can be a serious attack. Especially that a briber can reward users for participating early in the epoch. Let me know thoughts. I can further analyze this if there is contention about its impact.

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