Voting — But Private
Yesterday, the countries of the UK went to the polls.
It is the most basic of human rights and gives everyone a chance to give their say. Without it, the right to vote, we would have no ways to hold our governments to account. But, in the UK, we still use paper and a pen, and we still count our votes manually. We also put the votes into a van, and ship them off for counting. Surely, in the 21st Century, there’s a better way? And, so we might move in the future toward electronic voting, but how do we trust the votes, and also respect the privacy of the citizen? Well, it was David Chaum who investigated this problem, and who came up with blinded signatures.
Blind signatures
A blind signature allows Bob to hide the content of a message before it is signed by a trusted entity (the signer). This is typically used when the creator of a message is different to the entity which signs it. For example, Bob may blind the message (such as his vote), and then for Trent to sign it as being valid, but where Trent will not know the contents of the message (or his vote). This could thus be applied to voting systems, and where Bob registers his vote, and Trent then signs it as being a valid vote cast (using Trent’s signing key). Bob can then get this back, and unblind his message, and then cast the vote. The vote will thus contain Bob’s message but be signed by…
