It seems like a long time since I spent a very long afternoon (and evening) observing the electronic count of the London Elections. Yesterday, the Open Rights Group released its report on the count. The verdict?
there is insufficient evidence available to allow independent observers to state reliably whether the results declared in the May 2008 elections for the Mayor of London and the London Assembly are an accurate representation of voters’ intentions.
There was lots of nice machinery and pretty screens to watch, but in my view three more things were needed to ensure confidence in the vote.
- A display that showed (a random selection of) ballots and the corresponding vote recorded automatically.
- No machines connected to the network that could not be observed.
- A commitment to the vote (I mean this in the cryptographic sense) after which a manual recount of randomly selected ballot boxes.
The last point is technically tricky to do properly, but I think it could be achieved. For example, take the hash of each ballot box’s count, then form a Merkle tree from those. Publish the root of the tree as the commitment, then after the manual recount, show that the hashes of the (electronic) counts for those boxes (which you would have to reveal anyway to verify the recount) are consistent with the tree.