标题: 电子商务环境中网路拍卖系统之研究
Auction Systems over the Internet in Electronic Commerce
作者: 廖耕亿
Gen-Yih Liao
黄景彰
Jing-Jang Hwang
资讯管理研究所
关键字: 电子商务;线上拍卖;网际网路;公平性;隐私性;Electronic commerce;On-line auction;The Internet;Fairness;Privacy
公开日期: 2000
摘要: 网际网路技术的突飞猛进已经塑造出一个适合进行资料交易的环境。对于传统的拍卖活动来说,除了网际网路快捷的交易速度之外,竞标者可以利用无远弗届的网路搜集拍卖资讯,并且跨越地理藩篱寻找交易对象,拍卖活动因而成为电子商务的主要类型之一。
在各种不同形式的拍卖中,标单密封式拍卖的特点是标单在开标之前必须保持弥封。由于网际网路具有无法眼见为凭的特性,不易建立使用者对拍卖系统的信赖感,本论文首先根据标单密封式的拍卖规则,建立网路拍卖可能遭遇的攻击模式,然后归纳出网路拍卖系统应达成的公平性与隐私性需求。
根据这些需求,本论文检视了现有文献中具有代表性的拍卖系统。为了建立公平的拍卖环境,现有方法对于拍卖单位都进行了各种信赖假设,因此适合用在竞标者信赖拍卖单位的环境。当竞标者对卖方以及拍卖单位都感到陌生(例如C2C的交易环境)时,针对拍卖单位的信赖假设将不再成立,因此导致现有方法的不适用现象。
随着网际网路逐渐成为主要通讯媒体,保持使用者的隐私将有助于增加使用者对于系统的信赖。要满足竞标者的隐私性需求,一个拍卖系统应该能够在开标前保持竞标者身分的隐密性,而且要让未得标者的标单在决标后持续保持隐密。在我们所探讨的文献中,现有方法只能满足其中一项隐私性需求,而且必须依赖竞标者对于拍卖单位的信赖。
本论文提出了三个方法,其中方法一利用杂凑链的长度来代表标价,在竞标者不与拍卖单位共谋的前提下可以满足公平性需求。方法二是方法一的改进,并且加入了买方的角色,使得这个方法可以抵挡竞标者与拍卖单位的共谋攻击。方法三则运用“半标单”设计达成所有公平性与隐私性需求,而且竞标者对于拍卖单位的信赖假设只剩下拍卖单位诚实比较标价以及签发得标者证明。
本论文的研究有助于标单密封式拍卖系统的开发。方法一适合用于竞标者信赖拍卖单位的环境,方法二适用在竞标者可以信赖拍卖单位或卖方两者之一的环境。至于方法三,由于只需要对拍卖单位建立少数信赖假设,因此可以应用在竞标者对于拍卖单位与卖方都信赖不足的环境中。这是本论文的具体贡献,也是现有拍卖系统无法达成的。
现有文献经常根据所满足的系统需求来进行系统功能的比较,系统需求的达成其实与系统的信赖假设密切相关。因此,本论文根据信赖假设的对象归纳各系统所适用的拍卖环境,利用环境适合度作为拍卖系统的比较基础。除了比较结果可以提供拍卖环境经营者作为挑选拍卖系统的参考依据之外,根据环境适合度进行比较的论证方式可以作为资讯系统比较研究的参考,也是本论文的另一贡献。
The Internet has created a virtual cyberspace with a variety of possibilities, which have been difficult in the physical world. With its widespread connections, the global network can provide auction information and introduce transaction partners all over the world. This leads to on-line auction being as one major form of commercial activities in the Internet.
Auction itself has variations. Sealed bid auction features that all of the bids must keep confidential before being opening. This feature, enhancing fairness for bidders, proposes challenges to electronic auction in the Internet where physical verifications are no possibilities.
This thesis begins with establishing an abstract model of attacks in every steps of an auction. This model bases the requirements regarding fairness for Internet auction. Next, this study surveys representative works, and finds out the trust assumptions set in the works. Accordingly, most of these auction systems are practical for auction environments where bidders believe that the auctioneer obey auction rules. Conversely, if bidders cannot trust the auctioneer (as in C2C transactions), there will be a need for a new auction system putting less trust assumption on the auctioneer.
As the Internet attract more users, privacy becomes a more important issue. For Internet auction, an auction system should be able to keep identity of bidders uncovered, and to keep losing bids confidential. Our surveys show that none of proposed systems can fulfill both of the requirements for privacy.
This thesis proposes three auction systems. System 1, representing bid prices with the length of hash chains, can satisfy the fairness requirements, assuming no collustion of bidders with the auctioneer. System 2, a variation on the previous system, incorporates the role of sellers into the system, and remains immune while being attacked by collusion between a malicious bidder and the auctioneer. The last, with a novel design of ‘half-bids,’ fulfills all of the requirements regarding fairness and privacy, while assuming only two underlying premises: the auctioneer honestly compares bid prices and distributes a proof to the winner in an auction. These two assumptions can be verified with evidences.
Therefore, System 1 suites in an auction environment requiring bidders’ trust in the auctioneer, and System 2 relaxes the assumption by trusting either of the auctioneer and the seller. Moreover, with System 3 establishing slight assumptions of bidders in the auctioneer, it is suitable for auction environments, which lack confidence of bidders. This contribution improves auction systems over proposed systems in current literature.
This thesis suggests a novel approach to evaluating auction systems. Current literature compares auction systems according to their satisfied requirements. Since fulfilled requirements result from bidders’ trust assumptions, the assumptions determine suitability of an auction system to an auction environment. Instead of comparing fulfilled requirements, this thesis compares suitability of auction systems to different types of auction environments. In addition to provide insights for auction houses to choose among auction systems, the thesis offers an unprecedented view for comparing functionality of information systems.
URI: http://140.113.39.130/cdrfb3/record/nctu/#NT890396024
http://hdl.handle.net/11536/67044
显示于类别:Thesis