We present a practical protocol based on homomorphic cryptography for conducting provably fair sealed-bid auctions. The system preserves the secrecy of the bids, even after the announcement of auction results, while also providing for public verifiability of the correctness and trustworthiness of the outcome. No party, including the auctioneer, receives any information about bids before the auction closes, and no bidder is able to change or repudiate her 1 bid. The system is illustrated through application to first-price, uniformprice and second-price auctions, including multi-item auctions. Empirical results based on an analysis of a prototype demonstrate the practicality of our protocol for real-world applications. Key words: Auctions, auction theory, cryptographic auctions, cryptography, e-commerce, electronic transactions, homomorphic cryptography, security. 1 For clarity of reference, we use "she", "her", etc. to refer to the bidders and verifiers, and "h...
David C. Parkes, Michael O. Rabin, Stuart M. Shieb