Prêt à Voter is an E2E voting system devised by Peter Ryan of the University of Luxembourg. It aims to provide guarantees of accuracy of the count and ballot privacy that are independent of software, hardware etc. Assurance of accuracy flows from maximal transparency of the process, consistent with maintaining ballot privacy. In particular, Prêt à Voter enables voters to confirm that their vote is accurately included in the count whilst avoiding dangers of coercion or vote buying.

The key idea behind the Prêt à Voter approach is to encode the vote using a randomized candidate list. The randomisation of the candidate list on each ballot form ensures the secrecy of each vote. Incidentally, it also removes any bias towards the top candidate that can occur with a fixed ordering.

The value printed on the bottom of the receipt is the key to extraction of the vote. Buried cryptographically in this value is the information needed to reconstruct the candidate order and so extract the vote encoded on the receipt. This information is encrypted with secret keys shared across a number of tellers. Thus, only the set of tellers acting together are able to interpret the vote encoded on the receipt. No individual agent or machine involved in the election should ever be able to tie a particular voter to a particular decrypted vote.

After the election, voters (or perhaps proxies acting on their behalf) can visit the Web Bulletin Board (WBB) and confirm their receipts appear correctly. Once this is over, the tellers take over and perform anonymising mixes and decryption of the receipts. All the intermediate stages of this process are posted to the WBB and are audited later.

There are various auditing mechanisms to ensure that all the steps, the creation of the ballot forms, the mixing and decryption and so on were all performed correctly, but these are carefully designed so as not to impinge on ballot privacy.