Privacy and anonymity have become two factors of in-creasing importance in auction protocol. This paper provides an efficient sealed-bid electronic auction protocol based on the technique of ring signature and verifiable technique of encryption key chain. The peculiar characteristics of our protocol are non-repudiation of bidders but preserving their anonymity and allowing the auctioneer to determine the wining bid without revealing the losing bid. Our protocol has additional characteristics such as public verifiability, unforgeability, correctness and fairness.