Abstract: This paper proposes a multi-item electronic auction protocol by using the distributed version of ElGamal cipher. It is of high-level security because no auctioneer or trusted third parties is needed in this protocol and the auction outcome is obtained only when all the bidders submit their shares. The scheme is different from other protocols as it can be applied to the case that each bidder only buys one item as well as the case that one buys two or more items. Besides, its computational complexity is small and it is more applicable.

Key words: Electronic auction, Distributed version of ElGamal cipher, Homomorphism, Digital signature

摘要： 提出一种基于分布式ElGamal公钥密码体制的多拍卖物电子拍卖协议。该协议采用无拍卖行的方式对多个物品进行拍卖，使得整个计算过程仅有投标者参与，并且根据分布式ElGamal公钥密码体制的特点，只有当全部合法投标者共同提交自己的子密时，才能计算出该次拍卖活动的中标价以及中标者，因而提高了安全性。与以往协议不同，它不仅适用于一个投标者买一件物品的情况，也适用于一个投标者买多件物品的情况，计算量较少，更适合于实际情况。

关键词: 电子拍卖, 分布式ElGamal公钥密码体制, 同态性, 数字签字