Abstract
In recent years, the online auction of consumers' goods is an increasingly popular selling channel. To copy with this tendency, the bidders' convenience and security have to be considered. Some online auctions (such as eBay or Amazon) introduced a proxy bidding strategy that the bidder can decide a maximum bid and delegate his authority to a legal agent to automatically outbid other competitors for the last winner. In this paper, we identify some practical issues in the current bidding strategies and propose a system model of a pairing-based proxy signcryption which includes two cryptographic schemes; further, we apply the proposed schemes to the online proxy auction system for comparing two authorized online proxy auction policies (agents anonymity setting and agents accountability setting) with different applications of short message and long message. Also, we discuss some critical security issues under the online proxy auctions.