The design and implementation of a secure auction service

We present the design and implementation of a distributed service for performing sealed bid auctions. This service provides an interface by which clients, or “bidders”, can issue secret bids to the service for an advertised auction. Once the bidding period has ended, the auction service opens the bids, determines the winning bid, and provides the winning bidder with a ticket for claiming the item bid upon. Using novel cryptographic techniques, the service is constructed to provide strong protection for both the auction house and correct bidders, despite the malicious behavior of any number of bidders and fewer than one third of the servers comprising the auction service. Specifically, it is guaranteed that: bids of correct bidders are not revealed until after the bidding period has ended; the auction house collects payment for the winning bid; losing bidders forfeit no money; and only the winning bidder can collect the item bid upon. We also discuss techniques to enable anonymous bidding     

一种应用于双重数字签名的电子拍卖方案

针对电子拍卖中存在的身份匿名性等安全问题,基于秘密分享思想,提出一种安全高效的电子拍卖方案。应用双重数字签名,保证投标过程中参与者之间的信息传输安全。投标者采用临时身份投标,标价不直接发送给其他参与者。拍卖服务器根据单调递增函数所计算出的投标值判断中标者,若与注册中心计算结果相符,则投标结果有效。安全性分析结果表明,该方案满足电子拍卖的各项安全性要求,且计算简便、运算效率高。     

无收据的密封式电子拍卖协议

提出一个高效的无收据密封式电子拍卖协议，无收据的意义是在协议进行过程中没有可以作为“收据”的公开数据，从而能够更好地保证竞拍者的安全。与现有的无收据密封式电子拍卖协议相比，该文的协议在竞拍价格变化较大的情况下，效率有很大的提高。     

Implications of a Reserve Price in an Agent-Based Common-Value Auction

Auction sellers can use a reserve price to require a minimum bid before items are sold. Theoretical and experimental research has tested the influence of a reserve price in an independent private values auction, but little focus has been given to the influence of a reserve price in a first-price common-value auction. We establish an agent-based first-price common-value auction to determine the impact of the reserve price with two buyers and with three buyers. An agent-based approach to this problem is both a unique contribution to the literature and appropriate since finding analytical solutions with common-value auctions is difficult. The agent-based model approach also allows us to consider buyers that have non-symmetric bid functions. Furthermore, we introduce a combination of numerical integration techniques with a new particle swarm learning algorithm. The buyers in the model choose their expected-net-revenue-maximizing bid price, and sellers choose their expected-revenue-maximizing reserve price. In the two-buyer and three-buyer auction, a reserve price increases the equilibrium winning bid price, decreases the probability that the item is sold, and increases the seller’s expected revenue. A reserve price in a two-buyer auction increases the winning bid price more than including an additional buyer in the auction with no reserve price. However, due to only receiving a salvage value when the item does not sell in the auction, the seller’s expected revenue is higher in the three-buyer first-price common-value auction without a reserve price than in the two-buyer auction with a reserve price.     

A secure and privacy-preserving lightweight authentication protocol for wireless communications

In wireless networks, seamless roaming allows a mobile user (MU) to utilize its services through a foreign server (FS) when outside his home server (HS). However, security and efficiency of the authentication protocol as well as privacy of MUs are of great concern to achieve an efficient authentication protocol. Conventionally, authentication involves the participation of three entities (MU, HS, and FS); however, involving an HS in the authentication process incurs heavy computational burden on it due to huge amount of roaming requests. Moreover, wireless networks are often susceptible to various forms of passive and active attacks. Similarly, mobile devices have low processing, communication, and power capabilities.

In this paper, we propose an efficient, secure, and privacy-preserving lightweight authentication protocol for roaming MUs in wireless networks without engaging an HS. The proposed authentication protocol uses unlinkable pseudo-IDs and lightweight time-bound group signature to provide strong user anonymity, and a cost-effective cryptographic scheme to achieve security of the authentication protocol. Similarly, we implement a better billing system for MUs and a computationally efficient revocation scheme. Our analysis shows that the protocol has better performance than other related authentication protocols in wireless communications in terms of security, privacy, and efficiency.     

一种简单高效的密封式电子拍卖方案

针对目前大多数的电子拍卖方案都是假设存在一个可信第三方,使得电子拍卖的安全性有所降低的问题,提出一个基于不可信第三方的密封式电子拍卖方案。采用数字签名技术对竞拍者的身份进行验证,确保竞拍者身份的隐私性。在计算成交价时,基于离散对数求解的困难性,对竞拍价的二进制长度进行加密封装,保证竞拍价的秘密性以及结果的正确性。分析结果证明,该方案设计简单,安全性较高,在计算效率上相对于现有多数电子拍卖方案有较大的提高。     

一个M＋1电子拍卖方案的密码学分析

分析了伍前红等人最近提出的M＋1电子拍卖方案,指出该方案假设不同投标者的标价不同的前提条件是不能成立的;另一方面,当有多个投标者同时投了最高价或次高价时,协议将不能实现M＋1价住电子拍卖（称为结点问题）,因此方案不具有实用价值。给出了解决这一问题的有效算法。     

基于区块链的密封式投标拍卖方案

随着互联网技术的飞速发展,传统拍卖正逐渐转变为电子拍卖,其中隐私保护越来越受到关注。针对当前电子投标拍卖系统中出现的问题,如竞买人隐私存在被泄露的风险、第三方拍卖中心的费用昂贵、第三方拍卖中心可能与竞买人勾结等,提出一种基于区块链智能合约技术的密封式投标拍卖方案。该方案充分利用区块链的去中心化、防篡改和可信赖性等特征构建了一个无第三方的拍卖环境,并通过区块链上的安全保证金策略约束竞买人的行为,从而提高密封式电子拍卖的安全性。同时该方案利用Pedersen承诺保护竞买人的竞拍价格不被泄露,并通过Bulletproofs零知识证明协议验证中标价格的正确性。安全性分析和实验结果表明,提出的拍卖方案满足安全性要求,各个阶段的时间消耗均在可接受范围内,满足日常拍卖要求。     

基于歧视性的第二价格拍卖算法的激励机制

在基于对等网(P2P)的大数据实时应用中,针对如何遏制视频点播(VOD)系统中的节点搭便车行为,提出了基于歧视性的第二价格拍卖算法的激励机制。节点之间以分布式动态拍卖的方式获取各自所需视频数据块,拍卖中,拍卖节点首先根据歧视性原则判断竞标节点的预算是否足以参与竞标,并根据允许参与竞标的节点数目设置上传带宽;然后根据竞标节点的出价确定赢得竞标的节点;最后竞标节点在接收到数据块后根据第二价格方案支付拍卖节点仅次于拍卖最高价格的第二高价格的要价作为节点的收益。分析节点的收益、节点带宽的利用率以及贡献节点/自私节点的比例,表明该方案能有效地激励节点积极地参与视频数据块的共享,同时高效地利用节点的上传带宽。     

Searching and editing MPEG-compressed video in a distributed online environment

WebClip (on-line demo at http://www.ctr.columbia.edu/webclip) is a compressed video searching and editing system operating over the World Wide Web. WebClip uses a distributed client-server model including a server engine for content analysis/editing, and clients for interactive controls of video browsing/editing. It specializes several unique features, including compressed-domain video feature extraction and manipulation, multi-resolution video access, content based video browsing/retrieval, and a distributed network architecture.     

Quantum computation based bundling optimization for combinatorial auction in freight service procurements

Combinatorial auction is a useful trade manner for transportation service procurements in e-marketplaces. To enhance the competition of combinatorial auction, a novel auction mechanism of two-round bidding with bundling optimization is proposed. As the recommended the auction mechanism, the shipper/auctioneer integrates the objects into several bundles based on the bidding results of first round auction. Then, carriers/bidders bid for the object bundles in second round. The bundling optimization is described as a multi-objective model with two criteria on price complementation and combination consistency. A Quantum Evolutionary Algorithm (QEA) with β-based rotation gate and the encoding scheme based on non-zero elements in complementary coefficient matrix is developed for the model solution. Comparing with a Contrast Genetic Algorithm, QEA can achieve better computational performances for small and middle size problems.     

一个基于环签名的安全密封电子拍卖协议*

在拍卖过程中如何保护投标者隐私和身份以及防止中标者反悔是设计安全电子拍卖系统的关键技术。基于环签名思想的类群签名方案及同态公钥加密体制,设计了一个新的密封投标的电子拍卖协议。所给协议具有如下特点：安全性好,能够满足投标者匿名、投标价保密、不可否认性以及不可伪造等密封电子拍卖的所有安全性要求;对可信赖第三方的依赖小;安全性高、步骤简略。     

一种保护标价安全的电子拍卖方案

电子拍卖的一个热点问题是保护标价的秘密性，因为存在第三方不可信任或相互勾结．提出了一个实用的保护标价安全的电子拍卖方案，除了中标价以外，它在任何勾结攻击情况下都能保证投标者标价的秘密性，可以公开验证中标价的正确性，效率远远高于最近Brandt提出的方案．其实现只需要O（log2υ）轮通信，其中υ是标价的范围．投标者注册使用数字签名后能保证协议的不可伪造性、抗重放攻击性和不可否认性．协议中使用零知识证明的安全性保证了系统的鲁棒性．     

一种安全有效的多轮电子拍卖协议

在目前的密封式电子拍安中,都没有解决标价瓶颈问题,即有多个投标者同时提交了相同的获胜价位,有些方案仅仅把标价提高,所有的投标者再重新进行拍卖,这样既增加了计算量又增加了通信量,使拍卖效率很低。该文利用多项式的秘密共享和Bit承诺技术,给出了一个新的安全有效的电子拍卖方案。     

A non-parametric estimator for setting reservation prices in procurement auctions

Electronic auction markets collect large amounts of auction field data. This enables a structural estimation of the bid distributions and the possibility to derive optimal reservation prices. In this paper we propose a new approach to setting reservation prices. In contrast to traditional auction theory we use the buyer’s risk statement for getting a winning bid as a key criterion to set an optimal reservation price. The reservation price for a given probability can then be derived from the distribution function of the observed drop-out bids. In order to get an accurate model of this function, we propose a nonparametric technique based on kernel distribution function estimators and the use of order statistics. We improve our estimator by additional information, which can be observed about bidders and qualitative differences of goods in past auctions rounds (e.g. different delivery times). This makes the technique applicable to RFQs and multi-attribute auctions, with qualitatively differentiated offers.     

Visualizing combinatorial auctions

We propose a novel scheme to visualize combinatorial auctions; auctions that involve the simultaneous sale of multiple items. Buyers bid on complementary sets of items, or bundles, where the utility of securing all the items in the bundle is more than the sum of the utility of the individual items. Our visualizations use concentric rings divided into arcs to visualize the bundles in an auction. The arcs’ positions and overlaps allow viewers to identify and follow bidding strategies. Properties of color, texture, and motion are used to represent different attributes of the auction, including active bundles, prices bid for each bundle, winning bids, and bidders’ interests. Keyframe animations are used to show changes in an auction over time. We demonstrate our visualization technique on a standard testbed dataset generated by researchers to evaluate combinatorial auction bid strategies, and on recent Federal Communications Commission (FCC) auctions designed to allocate wireless spectrum licenses to cell phone service providers.     

基于可验证随机数的电子彩票方案

基于可验证随机函数且结合分层hash链结构设计了一种新的电子彩票方案。该方案能满足电子彩票的多种要求,在整个过程中不需要可信任第三方参与,并且Purchaser可轻松验证最终中奖数字是否伪造,具有匿名性、不可伪造性、不可重复性、公开验证性等安全特点。与其他方案进行比较,表明该方案的效率更高。     

Repeated Budgeted Second Price Ad Auction

Our main goal is to abstract existing repeated sponsored search ad auction mechanisms which incorporate budgets, and study their equilibrium and dynamics. Our abstraction has multiple agents bidding repeatedly for multiple identical items (such as impressions in an ad auction). The agents are budget limited and have a value per item. We abstract this repeated interaction as a one-shot game, which we call budget auction, where agents submit a bid and a budget, and then items are sold by a sequential second price auction. Once an agent exhausts its budget it does not participate in the proceeding auctions. Our main result shows that if agents bid conservatively (never bid above their value) then there always exists a pure Nash equilibrium. We also study simple dynamics of repeated budget auctions, showing their convergence to a Nash equilibrium for two agents and for multiple agents with identical budgets.     

Fuzzy rule optimization for online auction frauds detection based on genetic algorithm

Due to the huge amount of users and low entrance cost of online auction, there are a lot of online fraud cases in online auction sites. According to the IC3 reports from 2003 to 2010, we can understand the fraud cases and victims are increasing rapidly year by year. To improve the prevention of online auction frauds, this research will propose a hybrid approach to detect the fraudster accounts to help the users to identify which seller is more dangerous. In this research, we use social network analysis to produce the behavior features and transform these features into fuzzy rules which can represent the detection rules. Then optimize the fuzzy rules by genetic algorithms to build the auction fraud detection model. For implementation, we collect the real auction data from the online auction site http://www.ruten.com.tw which is the most popular auction site in Taiwan. Finally, we use the proposed features and methodologies to detect the fraudster accounts and find out the detection models of them. We hope the result of this research can help the website administrators to detect the possible collusive fraud groups easier in online auction.