An Anonymous Aution Protocol with a Single Non-trusted Center Using Binary Trees

Some works about an electronic auction protocol have been proposed. An electronic auction protocol should satisfy the following seven properties: (a)Fair of bidders; (b)Security of bids; (c)Anonymity; (d)Validity of winning bids; (e)Non-repudiation; (f)Robustness; and (g)Efficient bidding points. As for anonymity, previous protocols assume some entities like a dealer or plural centers to be trusted. In this paper, anonymity is realized without a trusted center, maintaining both computational and round complexity low. Furthermore, we represent a bid efficiently by using binary trees: for 2k bidding points, the size of the representation of bids is just k. Previous works investigating a sealed-bid auction aim at "efficiency" but not "entertainment" seen in English auction. We introduce a new idea of entertainment to the opening phase by decreasing winner candidates little by little. Our protocol has the following three main features in addition to the above seven properties: perfect anonymity(a single non-trusted center), efficient bidding points and entertainment.