Secure Auctions without Cryptography

International audience; An auction is a simple way of selling and buying goods. Modern auction protocols often rely on complex cryptographic operations to ensure manifold security properties such as bidder-anonymity or bid-privacy, non-repudiation, fairness or public verifiability of the result. This makes them difficult to understand for users who are not experts in cryptography. We propose two physical auction protocols inspired by Sako’s cryptographic auction protocol. In contrast to Sako’s protocol, they do not rely on cryptographic operations, but on physical properties of the manipulated mechanical objects to ensure the desired security properties. The first protocol only uses standard office material, whereas the second uses a special wooden box. We validate the security of our solutions using ProVerif.