A survey of privacy in multi-agent systems
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paper_title: A Taxonomy of Privacy

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Privacy is a concept in disarray. Nobody can articulate what it means. As one commentator has observed, privacy suffers from an embarrassment of meanings. Privacy is far too vague a concept to guide adjudication and lawmaking, as abstract incantations of the importance of privacy do not fare well when pitted against more concretely-stated countervailing interests. In 1960, the famous torts scholar William Prosser attempted to make sense of the landscape of privacy law by identifying four different interests. But Prosser focused only on tort law, and the law of information privacy is significantly more vast and complex, extending to Fourth Amendment law, the constitutional right to information privacy, evidentiary privileges, dozens of federal privacy statutes, and hundreds of state statutes. Moreover, Prosser wrote over 40 years ago, and new technologies have given rise to a panoply of new privacy harms. A new taxonomy to understand privacy violations is thus sorely needed. This article develops a taxonomy to identify privacy problems in a comprehensive and concrete manner. It endeavors to guide the law toward a more coherent understanding of privacy and to serve as a framework for the future development of the field of privacy law.
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paper_title: Network Security Essentials: Applications and Standards

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From the Book: ::: PREFACE: Preface In this age of electronic connectivity, of viruses and hackers, of electronic eavesdropping and electronic fraud, network security has assumed increasing importance. Two trends have come together to make the topic of this book of vital interest. First, the explosive growth in computer systems and their interconnections via networks has increased the dependence of both organizations and individuals on the information stored and communicated using these systems. This, in turn, has led to a heightened awareness of the need to protect data and resources from disclosure, to guarantee the authenticity of data and messages, and to protect systems from network-based attacks. Second, the disciplines of cryptography and network security have matured, leading to the development of practical, readily available applications to enforce network security. Objectives It is the purpose of this book to provide a practical survey of network security applications and standards. The emphasis is on applications that are widely used on the Internet and for corporate networks, and on standards, especially Internet standards, that have been widely deployed. Intended Audience The book is intended for both an academic and a professional audience. As a textbook, it is intended as a one-semester undergraduate course on network security for computer science, computer engineering, and electrical engineering majors. The book also serves as a basic reference volume and is suitable for self-study. Plan of the Book The book is organized in three parts: I. Cryptography: A concise survey of the cryptographic algorithms and protocols i reportunderlyingnetwork security applications, including encryption, hash functions, digital signatures, and key exchange. i See Appen~ II. Network Security Applications: Covers important network security tools and applications, including Kerberos, X.509v3 certificates, PGP, S/MIME, IP Secu- rity, SSL/TLS, SET, and SNMPv3. III. System Security: Looks at system-level security issues, including the threat of and countermeasures for intruders and viruses, and the use of firewalls and trusted systems. This book i A more detailed, chapter-by-chapter summary appears at the end of Chapter ~ (CNS2e). 1. In addition, the book includes an extensive glossary, a list of frequently used detailed an< acronyms, and a bibliography. There are also end-of-chapter problems and sugges- of which co tions for further reading. dards (NSE 3. NSE1e in covers SNh Internet Services for Instructors and Students There is a Web page for this book that provides support for students and instruc tors. The page includes links to relevant sites, transparency masters of figures in the book in PDF (Adobe Acrobat) format, and sign-up information for the book's Internet mailing list. The Web page is at ...
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paper_title: All your contacts are belong to us: automated identity theft attacks on social networks

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Social networking sites have been increasingly gaining popularity. Well-known sites such as Facebook have been reporting growth rates as high as 3% per week. Many social networking sites have millions of registered users who use these sites to share photographs, contact long-lost friends, establish new business contacts and to keep in touch. In this paper, we investigate how easy it would be for a potential attacker to launch automated crawling and identity theft attacks against a number of popular social networking sites in order to gain access to a large volume of personal user information. The first attack we present is the automated identity theft of existing user profiles and sending of friend requests to the contacts of the cloned victim. The hope, from the attacker's point of view, is that the contacted users simply trust and accept the friend request. By establishing a friendship relationship with the contacts of a victim, the attacker is able to access the sensitive personal information provided by them. In the second, more advanced attack we present, we show that it is effective and feasible to launch an automated, cross-site profile cloning attack. In this attack, we are able to automatically create a forged profile in a network where the victim is not registered yet and contact the victim's friends who are registered on both networks. Our experimental results with real users show that the automated attacks we present are effective and feasible in practice.
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paper_title: Anonymous Communications for Mobile Agents

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Anonymous communication techniques are vital for some types of e-commerce applications. There have been several different approaches developed for providing anonymous communication over the Internet. In this paper, we review key techniques for anonymous communication and describe an alternate anonymous networking approach based on agile agents intended to provide anonymous communication protection for mobile agent systems.
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paper_title: The Right to Privacy

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hat the individual shall have full protection in person and in property is a principle as old as the common law; but it has been found necessary from time to time to define anew the exact nature and extent of such protection. Political, social, and economic changes entail the recognition of new rights, and the common law, in its eternal youth, grows to meet the new demands of society. Thus, in very early times, the law gave a remedy only for physical interference with life and property, for trespasses vi et armis. Then the "right to life" served only to protect the subject from battery in its various forms; liberty meant freedom from actual restraint; and the right to property secured to the individual his lands and his cattle. Later, there came a recognition of man's spiritual nature, of his feelings and his intellect. Gradually the scope of these legal rights broadened; and now the right to life has come to mean the right to enjoy life, -the right to be let alone; the right to liberty secures the exercise of extensive civil privileges; and the term "property" has grown to comprise every form of possession -intangible, as well as tangible.
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paper_title: Privacy and Artificial Agents, or, Is Google Reading My Email?

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We investigate legal and philosophical notions of privacy in the context of artificial agents. Our analysis utilizes a normative account of privacy that defends its value and the extent to which it should be protected: privacy is treated as an interest with moral value, to supplement the legal claim that privacy is a legal right worthy of protection by society and the law. We argue that the fact that the only entity to access my personal data (such as email) is an artificial agent is irrelevant to whether a breach of privacy has occurred. What is relevant are the capacities of the agent: what the agent is both able and empowered to do with that information. We show how concepts of legal agency and attribution of knowledge gained by agents to their principals are crucial to understanding whether a violation of privacy has occurred when artificial agents access users' personal data. As natural language processing and semantic extraction used in artificial agents become increasingly sophisticated, so the corporations that deploy those agents will be more likely to be attributed with knowledge of their users' personal information, thus triggering significant potential legal liabilities.
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paper_title: A study of preferences for sharing and privacy

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We describe studies of preferences about information sharing aimed at identifying fundamental concerns with privacy and at understanding how people might abstract the details of sharing into higher-level classes of recipients and information that are treated similarly. Thirty people specified what information they are willing to share with whom.. Although people vary in their overall level of comfort in sharing, we identified key classes of recipients and information. Such abstractions highlight the promise of developing expressive controls for sharing and privacy.
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paper_title: Unpacking "privacy" for a networked world

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Although privacy is broadly recognized as a dominant concern for the development of novel interactive technologies, our ability to reason analytically about privacy in real settings is limited. A lack of conceptual interpretive frameworks makes it difficult to unpack interrelated privacy issues in settings where information technology is also present. Building on theory developed by social psychologist Irwin Altman, we outline a model of privacy as a dynamic, dialectic process. We discuss three tensions that govern interpersonal privacy management in everyday life, and use these to explore select technology case studies drawn from the research literature. These suggest new ways for thinking about privacy in socio-technical environments as a practical matter.
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paper_title: Advances in Artificial Intelligence for Privacy Protection and Security

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In this book, we aim to collect the most recent advances in artificial intelligence techniques (i.e. neural networks, fuzzy systems, multi-agent systems, genetic algorithms, image analysis, clustering, etc), which are applied to the protection of privacy and security. The symbiosis between these fields leads to a pool of invigorating ideas, which are explored in this book. On the one hand, individual privacy protection is a hot topic and must be addressed in order to guarantee the proper evolution of a modern society. On the other, security can invade individual privacy, especially after the appearance of new forms of terrorism. In this book, we analyze these problems from a new point of view.
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paper_title: Privacy, economics, and price discrimination on the Internet

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The rapid erosion of privacy poses numerous puzzles. Why is it occurring, and why do people care about it? This paper proposes an explanation for many of these puzzles in terms of the increasing importance of price discrimination. Privacy appears to be declining largely in order to facilitate difierential pricing, which ofiers greater social and economic gains than auctions or shopping agents. The thesis of this paper is that what really motivates commercial organizations (even though they often do not realize it clearly themselves) is the growing incentive to price discriminate, coupled with the increasing ability to price discriminate. It is the same incentive that has led to the airline yield management system, with a complex and constantly changing array of prices. It is also the same incentive that led railroads to invent a variety of price and quality difierentiation schemes in the 19th century. Privacy intrusions serve to provide the information that allows sellers to determine buyers' willingness to pay. They also allow monitoring of usage, to ensure that arbitrage is not used to bypass discriminatory pricing.Economically, price discrimination is usually regarded as desirable, since it often increases the efficiency of the economy. That is why it is frequently promoted by governments, either through explicit mandates or through indirect means. On the other hand, price discrimination often arouses strong opposition from the public.There is no easy resolution to the conflict between sellers; incentives to price discriminate and buyers' resistance to such measures. The continuing tension between these two factors will have important consequences for the nature of the economy. It will also determine which technologies will be adopted widely. Governments will likely play an increasing role in controlling pricing, although their roles will continue to be ambiguous. Sellers are likely to rely to an even greater extent on techniques such as bundling that will allow them to extract more consumer surplus and also to conceal the extent of price discrimination. Micropayments and auctions are likely to play a smaller role than is often expected. In general, because of strong conflicting pressures, privacy is likely to prove an intractable problem that will be prominent on the the public agenda for the foreseeable future.
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paper_title: Electronic Agents and Privacy: A Cyberspace Odyssey 2001

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In this paper, analysis is carried out of the impact of the use of electronic agents on privacy and related interests. A preliminary examination is made of the various risks to privacy occasioned by agent operations and of the way in which current data protection rules can mitigate these risks. It is suggested that greater thought be given to drafting data protection rules that take full account of electronic agents. 1. Visions of agents Gareth Morgan has persuasively shown that we tend to view and understand organisations using various metaphorical images that often work at a subconscious, intuitive level. The same point can be made with respect to electronic agents. Concomitantly, how we perceive the impact of electronic agents on privacy will tend to be shaped in part by certain visions of what electronic agents are and are capable of becoming. As Morgan correctly shows in relation to organisations, such visions are not just interpretive constructs; they also provide frameworks for policy and action, including law making. Thus, when analysing the interrelationship of electronic agents and privacy, we must not lose sight of the influence of these images. Of the various visions of electronic agents which appear to dominate public discourse, two deserve to be singled out for special attention in light of the theme of this paper. The first vision is that of the electronic agent as ‘digital secretary’ and/or ‘digital butler’. This image depicts the agent as subservient and beneficent in relation to its users and indeed wider society. One of the 1 B.A.(Hons.), LL.B.(Hons.) (Australian National University); Dr. Juris / LL.D. (Oslo); Senior Research Fellow at the Norwegian Research Centre for Computers and Law, University of Oslo; Barrister of the Supreme Court of New South Wales. Thanks go to Graham Greenleaf for helpful comments on an earlier draft of this paper. This paper has been written in the framework of the ECLIP II project (Electronic Commerce Legal Issues Platform) funded by the European Commission under the specific programme for research, technological development and demonstration on a user-friendly information society (the IST programme). This paper, though, is solely the responsibility of the author and does not represent the opinion of the other contributors to ECLIP or of the European Community, nor is the European Community responsible for any use that might be made of data appearing in this paper. General information on ECLIP is available at http://www.eclip.org/. 2 Morgan, Images of Organization (Sage: London 1986). Morgan identifies a range of such images: e.g. organisations as machines, organisms, brains, cultures, political systems, pyschic prisons, processes of flux and transformation, and instruments of domination. 3 By ‘electronic agent’ is meant a software application which, with some degree of autonomy, mobility and learning capacity, executes specific tasks for a computer user or computer system. See further the paper by Weitzenboeck in this volume. Cf. commentary infra n. 9.
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paper_title: Engineering Privacy

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In this paper we integrate insights from diverse islands of research on electronic privacy to offer a holistic view of privacy engineering and a systematic structure for the discipline's topics. First we discuss privacy requirements grounded in both historic and contemporary perspectives on privacy. We use a three-layer model of user privacy concerns to relate them to system operations (data transfer, storage and processing) and examine their effects on user behavior. In the second part of the paper we develop guidelines for building privacy-friendly systems. We distinguish two approaches: "privacy-by-policy" and "privacy-by-architecture." The privacy-by-policy approach focuses on the implementation of the notice and choice principles of fair information practices (FIPs), while the privacy-by-architecture approach minimizes the collection of identifiable personal data and emphasizes anonymization and client-side data storage and processing. We discuss both approaches with a view to their technical overlaps and boundaries as well as to economic feasibility. The paper aims to introduce engineers and computer scientists to the privacy research domain and provide concrete guidance on how to design privacy-friendly systems.
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paper_title: Agent Technology for e-Commerce

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List of Figures. List of Tables. Preface. 1 Introduction. 1.1 A paradigm shift. 1.2 Electronic commerce. 1.3 Agents and e-commerce. 1.4 Further reading. 1.5 Exercises and topics for discussion. 2 Software agents. 2.1 Characteristics of agents. 2.2 Agents as intentional systems. 2.3 Making decisions. 2.4 Planning. 2.5 Learning. 2.6 Agent architectures. 2.7 Agents in perspective. 2.8 Methodologies and languages. 2.9 Further reading. 2.10 Exercises and topics for discussion. 3 Multi-agent systems. 3.1 Characteristics of multi-agent systems. 3.2 Interaction. 3.3 Agent communication. 3.4 Ontologies. 3.5 Cooperative problem solving. 3.6 Virtual organisations as multi-agent systems. 3.7 Infrastructure requirements for open multi-agent systems. 3.8 Further reading. 3.9 Exercises and topics for discussion. 4 Shopping Agents. 4.1 Consumer buying behaviour model. 4.2 Comparison shopping. 4.3 Working for the user. 4.4 How shopping agents work. 4.5 Limitations and issues. 4.6 Further reading. 4.7 Exercises and topics for discussion. 5 Middle agents. 5.1 Matching. 5.2 Classification of middle agents. 5.3 Describing capabilities. 5.4 LARKS. 5.5 OWL-S. 5.6 Further reading. 5.7 Exercises and topics for discussion. 6 Recommender systems. 6.1 Information needed. 6.2 Providing recommendations. 6.3 Recommendation technologies. 6.4 Content-based filtering. 6.5 Collaborative filtering. 6.6 Combining content and collaborative filtering. 6.7 Recommender systems in e-commerce. 6.8 A note on personalization. 6.9 Further reading. 6.10 Exercises and topics for discussion. 7 Elements of strategic interaction. 7.1 Elements of Economics. 7.2 Elements of Game Theory. 7.3 Further reading. 7.4 Exercises and topics for discussion. 8 Negotiation I. 8.1 Negotiation protocols. 8.2 Desired properties of negotiation protocols. 8.3 Abstract architecture for negotiating agents. 8.4 Auctions. 8.5 Classification of auctions. 8.6 Basic auction formats. 8.7 Double auctions. 8.8 Multi-attribute auctions. 8.9 Combinatorial auctions. 8.10 Auction platforms. 8.11 Issues in practical auction design. 8.12 Further reading. 8.13 Exercises and topics for discussion. 9 Negotiation II. 9.1 Bargaining. 9.2 Negotiation in different domains. 9.3 Coalitions. 9.4 Applications of coalition formation. 9.5 Social choice problems. 9.6 Argumentation. 9.7 Further reading. 9.8 Exercises and topics for discussion. 10 Mechanism design. 10.1 The mechanism design problem. 10.2 Dominant strategy implementation. 10.3 The Gibbard-Satterthwaite Impossibility Theorem. 10.4 The Groves-Clarke mechanisms. 10.5 Mechanism design and computational issues. 10.6 Further reading. 10.7 Exercises and topics for discussion. 11 Mobile agents. 11.1 Introducing mobility. 11.2 Facilitating mobility. 11.3 Mobile agent systems. 11.4 Aglets. 11.5 Mobile agent security. 11.6 Issues on mobile agents. 11.7 Further reading. 11.8 Exercises and topics for discussion. 12 Trust, security and legal issues. 12.1 Perceived risks. 12.2 Trust. 12.3 Trust in e-commerce. 12.4 Electronic institutions. 12.5 Reputation systems. 12.6 Security. 12.7 Cryptography. 12.8 Privacy, anonymity and agents. 12.9 Agents and the law. 12.10 Agents as legal persons. 12.11 Closing remarks. 12.12 Further reading. 12.13 Exercises and topics for discussion. A Introduction to decision theory. A.2 Making decisions. A.3 Utilities. A.4 Further reading. Bibliography. Index.
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paper_title: Information privacy: measuring individuals' concerns about organizational practices

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Information privacy has been called one of the most important ethical issues of the informa1 Alien Lee was the accepting senior for this paper. tion age. Public opinion polls show rising levels of concer about privacy among Americans. Against this backdrop, research into issues associated with information privacy is increasing. Based on a number of preliminary studies, it has become apparent that organizational practices, individuals' perceptions of these practices, and societal responses are inextricably linked in many ways. Theories regarding these relationships are slowly emerging. Unfortunately, researchers attempting to examine such relationships through confirmatory empirical approaches may be impeded by the lack of validated instruments for measuring individuals' concerns about organizational information privacy practices. To enable future studies in the information privacy research stream, we developed and validated an instrument that identifies and measures the primary dimensions of individuals' concers about organizational information privacy practices. The development process included examinations of privacy literature; experience surveys and focus groups; and the use of expert judges. The result was a parsimonious 15-item instrument with four subscales tapping into dimensions of individuals' concerns about organizational information privacy practices. The instrument was rigorously tested and validated across several heterogenous populations, providing a high degree of confidence in the scales' validity, reliability, and generalizability.
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paper_title: Privacy in e-commerce: examining user scenarios and privacy preferences

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Privacy is a necessary concern in electronic commerce. It is difficult, if not impossible, to complete a transaction without revealing some personal data ‐ a shipping address, billing information, or product preference. Users may be unwilling to provide this necessary information or even to browse online if they believe their privacy is invaded or threatened. Fortunately, there are technologies to help users protect their privacy. P3P (Platform for Privacy Preferences Project) from the World Wide Web Consortium is one such technology. However, there is a need to know more about the range of user concerns and preferences about privacy in order to build usable and effective interface mechanisms for P3P and other privacy technologies. Accordingly, we conducted a survey of 381 U.S. Net users, detailing a range of commerce scenarios and examining the participants' concerns and preferences about privacy. This paper presents both the findings from that study as well as their design implications.
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paper_title: Engineering Privacy

paper_content:

In this paper we integrate insights from diverse islands of research on electronic privacy to offer a holistic view of privacy engineering and a systematic structure for the discipline's topics. First we discuss privacy requirements grounded in both historic and contemporary perspectives on privacy. We use a three-layer model of user privacy concerns to relate them to system operations (data transfer, storage and processing) and examine their effects on user behavior. In the second part of the paper we develop guidelines for building privacy-friendly systems. We distinguish two approaches: "privacy-by-policy" and "privacy-by-architecture." The privacy-by-policy approach focuses on the implementation of the notice and choice principles of fair information practices (FIPs), while the privacy-by-architecture approach minimizes the collection of identifiable personal data and emphasizes anonymization and client-side data storage and processing. We discuss both approaches with a view to their technical overlaps and boundaries as well as to economic feasibility. The paper aims to introduce engineers and computer scientists to the privacy research domain and provide concrete guidance on how to design privacy-friendly systems.
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paper_title: An agent‐based privacy‐enhancing model

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Purpose – The purpose of this paper is to discuss a privacy‐enhancing model, which is designed to help web users protect their private information. The model employs a collection of software agents. Privacy‐related decisions are made based on Platform for Privacy Preferences Project (P3P) information collected by the agents.Design/methodology/approach – Based on P3P information collected and user preferences, the software agents play a role in the decision‐making process. This paper presents the design of the agent‐based privacy‐enhancing model and considers the benefits and utility of such an approach.Findings – It is argued that the approach is feasible and it provides an effective solution to the usability limitations associated with P3P.Research limitations/implications – The paper focuses primarily on usability issues related to P3P. Consequently, some of the ancillary security‐related issues that arise are not covered in detail. Also the paper does not cover the development of an appropriate ontolog...
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paper_title: Sensitive Data Transaction in Hippocratic Multi-Agent Systems

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The current evolution of Information Technology leads to the increase of automatic data processing over multiple information systems. The data we deal with concerns sensitive information about users or groups of users. A typical problem in this context concerns the disclosure of confidential identity data. To tackle this difficulty, we consider in this paper the context of Hippocratic Multi-Agent Systems (HiMAS), a model designed for the privacy management. In this context, we propose a common content language combining meta-policies and application context data on one hand and on the other hand an interaction protocol for the exchange of sensitive data. Based on this proposal, agents providing sensitive data are able to check the compliance of the consumers to the HiMAS principles. The protocol that we propose is validated on a distributed calendar management application.
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paper_title: Privacy-Aware Autonomous Agents for Pervasive Healthcare

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Hospitals are convenient settings for deploying pervasive computing technology, but they also raise important privacy concerns. Hospital work imposes significant demands on staff, including high availability, careful attention to patients, confidentiality, rapid response to emergencies, and constant coordination with colleagues. These demands shape the way hospital workers experience and understand privacy. In addition, healthcare professionals experience a high level of mobility because they must collaborate with colleagues and access information and artifacts distributed throughout the premises. Autonomous agents can help developers design privacy-aware systems that handle the threats raised by pervasive technology
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paper_title: Information Sharing among Autonomous Agents in Referral Networks ⋆

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Referral networks are a kind of P2P system consisting of autonomous agents who seek and provide services, or refer other service providers. Key applications include service discovery and selection, and knowledge sharing. An agent seeking a service contacts other agents to discover suitable service providers. An agent who is contacted may autonomously ignore the request or respond by providing the desired service or giving a referral. This use of referrals is inspired by human interactions, where referrals are a key basis for judging the trustworthiness of a given service. The use of referrals differentiates such networks from traditional P2P information sharing systems, which are based on request flooding. Not only does the use of referrals enable an agent to control how its request is processed, it also provides an architectural basis for four kinds of interaction policies. InterPol is a language and framework supporting such policies. ::: ::: InterPol provides an ability to specify requests with hard and soft constraints as well as a vocabulary of application-independent terms based on interaction concepts. Using these, InterPol enables agents to reveal private information and accept others' information based on subtle relationships. In this manner, InterPol goes beyond traditional referral and other P2P systems in supporting practical applications. InterPol has been implemented using a Datalog-based policy engine for each agent. It has been applied on scenarios from a (multinational) health care project. The contribution of this paper is in a general referrals-based architecture for information sharing among autonomous agents, which is shown to effectively capture a variety of privacy and trust requirements of autonomous users.
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paper_title: HIPPOCRATIC MULTI-AGENT SYSTEMS

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The current evolution of Information Technology leads to the increase of automatic data processing over multiple information systems. In this context, the lack of user’s control on their personal data leads to the crucial question of their privacy preservation. A typical example concerns the disclosure of confidential identity information, without the owner’s agreement. This problem is stressed in multi-agent systems (MAS) where users delegate their control on their personal data to autonomous agents. Interaction being one of the main mechanism in MAS, sensitive information exchange and processing are a key issue with respect to privacy. In this article, we propose a model, ”Hippocratic Multi-Agent System” (HiMAS), to tackle this problem. This model defines a set of principles bearing on an agency to preserve privacy. In order to illustrate our model, we have chosen the concrete application of decentralized calendars management.
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paper_title: A Utility-Theoretic Approach to Privacy and Personalization

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Online services such as web search, news portals, and e-commerce applications face the challenge of providing high-quality experiences to a large, heterogeneous user base. Recent efforts have highlighted the potential to improve performance by personalizing services based on special knowledge about users. For example, a user's location, demographics, and search and browsing history may be useful in enhancing the results offered in response to web search queries. However, reasonable concerns about privacy by both users, providers, and government agencies acting on behalf of citizens, may limit access to such information. We introduce and explore an economics of privacy in personalization, where people can opt to share personal information in return for enhancements in the quality of an online service. We focus on the example of web search and formulate realistic objective functions for search efficacy and privacy. We demonstrate how we can identify a near-optimal solution to the utility-privacy tradeoff. We evaluate the methodology on data drawn from a log of the search activity of volunteer participants. We separately assess users' preferences about privacy and utility via a large-scale survey, aimed at eliciting preferences about peoples' willingness to trade the sharing of personal data in returns for gains in search efficiency. We show that a significant level of personalization can be achieved using only a small amount of information about users.
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paper_title: Trading privacy for trust

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Both privacy and trust relate to knowledge about an entity. However, there is an inherent conflict between trust and privacy: the more knowledge a first entity knows about a second entity, the more accurate should be the trustworthiness assessment; the more knowledge is known about this second entity, the less privacy is left to this entity. This conflict needs to be addressed because both trust and privacy are essential elements for a smart working world. The solution should allow the benefit of adjunct trust when entities interact without too much privacy loss. We propose to achieve the right trade-off between trust and privacy by ensuring minimal trade of privacy for the required trust. We demonstrate how transactions made under different pseudonyms can be linked and careful disclosure of such links fulfils this right trade-off.
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paper_title: Self-disclosure decision making based on intimacy and privacy

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Autonomous agents may encapsulate their principals' personal data attributes. These attributes may be disclosed to other agents during agent interactions, producing a loss of privacy. Thus, agents need self-disclosure decision-making mechanisms to autonomously decide whether disclosing personal data attributes to other agents is acceptable or not. Current self-disclosure decision-making mechanisms consider the direct benefit and the privacy loss of disclosing an attribute. However, there are many situations in which the direct benefit of disclosing an attribute is a priori unknown. This is the case in human relationships, where the disclosure of personal data attributes plays a crucial role in their development. In this paper, we present self-disclosure decision-making mechanisms based on psychological findings regarding how humans disclose personal information in the building of their relationships. We experimentally demonstrate that, in most situations, agents following these decision-making mechanisms lose less privacy than agents that do not use them.
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paper_title: Network Security Essentials: Applications and Standards

paper_content:

From the Book: ::: PREFACE: Preface In this age of electronic connectivity, of viruses and hackers, of electronic eavesdropping and electronic fraud, network security has assumed increasing importance. Two trends have come together to make the topic of this book of vital interest. First, the explosive growth in computer systems and their interconnections via networks has increased the dependence of both organizations and individuals on the information stored and communicated using these systems. This, in turn, has led to a heightened awareness of the need to protect data and resources from disclosure, to guarantee the authenticity of data and messages, and to protect systems from network-based attacks. Second, the disciplines of cryptography and network security have matured, leading to the development of practical, readily available applications to enforce network security. Objectives It is the purpose of this book to provide a practical survey of network security applications and standards. The emphasis is on applications that are widely used on the Internet and for corporate networks, and on standards, especially Internet standards, that have been widely deployed. Intended Audience The book is intended for both an academic and a professional audience. As a textbook, it is intended as a one-semester undergraduate course on network security for computer science, computer engineering, and electrical engineering majors. The book also serves as a basic reference volume and is suitable for self-study. Plan of the Book The book is organized in three parts: I. Cryptography: A concise survey of the cryptographic algorithms and protocols i reportunderlyingnetwork security applications, including encryption, hash functions, digital signatures, and key exchange. i See Appen~ II. Network Security Applications: Covers important network security tools and applications, including Kerberos, X.509v3 certificates, PGP, S/MIME, IP Secu- rity, SSL/TLS, SET, and SNMPv3. III. System Security: Looks at system-level security issues, including the threat of and countermeasures for intruders and viruses, and the use of firewalls and trusted systems. This book i A more detailed, chapter-by-chapter summary appears at the end of Chapter ~ (CNS2e). 1. In addition, the book includes an extensive glossary, a list of frequently used detailed an< acronyms, and a bibliography. There are also end-of-chapter problems and sugges- of which co tions for further reading. dards (NSE 3. NSE1e in covers SNh Internet Services for Instructors and Students There is a Web page for this book that provides support for students and instruc tors. The page includes links to relevant sites, transparency masters of figures in the book in PDF (Adobe Acrobat) format, and sign-up information for the book's Internet mailing list. The Web page is at ...
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paper_title: Managing business with electronic commerce : issues and trends

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Because the field of electronic commerce has continued to expand so significantly in recent years, it has become necessary for businesses and organizations to address ways to develop successful business application that aid in its effective utilization. This work addresses this important need and is intended for students, practitioners, researchera and also a general audience with an interest in this field.
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paper_title: A performance evaluation of three multiagent platforms

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In the last few years, many researchers have focused on testing the performance of Multiagent Platforms. Results obtained show a lack of performance and scalability on current Multiagent Platforms, but the existing research does not tackle poor efficiency causes. This article is aimed not only at testing the performance of Multiagent Platforms but also the discovery of Multiagent Platform design decisions that can lead to these deficiencies. Therefore, we are able to understand to what extent the internal design of a Multiagent Platform affects its performance. The experiments performed are focused on the features involved in agent communication.
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paper_title: Enforcing security in the AgentScape middleware

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Multi Agent Systems (MAS) provide a useful paradigm for accessing distributed resources in an autonomic and self-directed manner. Resources, such as web services, are increasingly becoming available in large distributed environments. Currently, numerous multi agent systems are available. However, for the multi agent paradigm to become a genuine mainstream success certain key features need to be addressed: the foremost being security. While security has been a focus of the MAS community, configuring and managing such multi agent systems typically remains non-trivial. Well defined and easily configurable security policies address this issue. A security architecture that is both flexible and featureful is prerequisite for a MAS. A novel security policy enforcement system for multi agent middleware systems is introduced. The system facilitates a set of good default configurations but also allows extensive scope for users to develop customised policies to suit their individual needs. An agent middleware, AgentScape, is used to illustrate the system.
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paper_title: A Secure Mobile Agents Platform

paper_content:

Mobile Agents is a new paradigm for distributed computing where security is very essential to the acceptance of this paradigm in a large scale distributed environment. In this paper, we propose protection mechanisms for mobile agents. In these mechanisms, the authentication of mobile agents and the access control to the system resources are controlled by the mobile-agents platform. Each agent defines its own access control policy with regard to other agents using an Interface Definition Language (IDL), thus enforcing modularity and easing programming task. An evaluation of these mechanisms has been conducted. The measurements give the overhead involved by the proposed protection mechanisms to the performance of mobile agents. An important advantage of our protection mechanisms are transparency to agents and the portability of nonsecure applications onto a secure environment. A mobile agent system and the protection mechanisms have been implemented. Our experiments have shown the feasibility and the advantages of our mechanisms.
---
paper_title: ADK: An Agent Development Kit Based on a Formal Design Model for Multi-Agent Systems

paper_content:

The advent of multi-agent systems has brought us opportunities for the development of complex software that will serve as the infrastructure for advanced distributed applications. During the past decade, there have been many agent architectures proposed for implementing agent-based systems, and also a few efforts to formally specify agent behaviors. However, research on narrowing the gap between agent formal models and agent implementation is rare. In this paper, we propose a model-based approach to designing and implementing intelligent agents for multi-agent systems (MAS). Instead of using formal methods for the purpose of specifying agent behavior, we bring formal methods into the design phase of the agent development life cycle. Specifically, we use the formalism called agent-oriented G-net model, which is based on the G-net formalism (a type of high-level Petri net), to serve as the high-level design for intelligent agents. Based on the high-level design, we further derived the agent architecture and the detailed design for agent implementation. To demonstrate the feasibility of our approach, we developed the toolkit called ADK (Agent Development Kit) that supports rapid development of intelligent agents for multi-agent systems and we discuss the role of inheritance in agent-oriented development. As a potential solution for automated software development, we summarize the procedure to generate a model-based design of application-specific agents. Finally, to illustrate an application built on ADK, we present an air-ticket trading example.
---
paper_title: Concepts and architecture of a security-centric mobile agent server

paper_content:

Mobile software agents are software components that are able to move in a network. They are often considered as an attractive technology in electronic commerce applications. Although security concerns prevail. We describe the architecture and concepts of the SeMoA server-a runtime environment for Java-based mobile agents. Its architecture has a focus on security and easy extendability, and offers a framework for transparent content inspection of agents by means of filters. We implemented filters that handle agent signing and authentication as well as selective encryption of agent contents. Filters are applied transparently such that agents need not be aware of the security services provided by the server.
---
paper_title: A group-oriented secure multiagent platform

paper_content:

Security is becoming a major concern in multiagent systems, since an agent's incorrect or inappropriate behaviour may cause non-desired effects, such as money and data loss. Some multiagent platforms (MAP) are now providing baseline security features, such as authentication, authorization, integrity and confidentiality. However, they fail to support other features related to the sociability skills of agents such as agent groups. What is more, none of the listed MAPs provide a mechanism for preserving the privacy of the users (regarding their identities) that run their agents on such MAPs. In this paper, we present the security infrastructure (SI) of the Magentix MAP, which supports agent groups and preserves user identity privacy. The SI is based on identities that are assigned to all the different entities found in Magentix (users, agents and agent groups). We also provide an evaluation of the SI describing an example application built on top of Magentix and a performance evaluation of it. Copyright © 2010 John Wiley & Sons, Ltd.
---
paper_title: Privacy protection in electronic commerce – a theoretical framework

paper_content:

In this paper, a theoretical framework for privacy protection in electronic commerce is provided. This framework allows us to identify the key players and their interactions in the context of privacy violation and protection. It also helps to discover the responsibilities of the key players and areas for further research.
---
paper_title: The Froehlich/Kent encyclopedia of telecommunications

paper_content:

"Wireless Multiple Access Adaptive Communications Technique, Gregory J. Pottie Wireless Networking, Asuncion Satamaria and F. J. Lopez-Hernandez Wireless Packet Data Technology, Apostolis K. Salkintzis and Christodoulos Chamzas Wireless Radio Software Architecture, Joseph Mitola Wireless Receivers Using Digitization at the RF or IF, Jeffrey A. Wepman Wireline and Wireless Applications for Intelligent Transportation Systems, Kevin Needham, Matthew McDonald, and Matthew Hardison Workbench for Security Officers, Allison Anderson, Lam For Kwok, and Dennis Longley World Wide Web and Internet Numbering and Naming Systems, Jon Postel and Joyce K. Reynolds The World Wide Web (WWW) and Secure Electronic Commerce, S. H. Von Solms Zworykin, Vladimir Kosma, Joyce E. Bedi Epilogue---New Communications Services---What Does Society Want?, Robert W. Lucky "
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paper_title: An agent-based approach for privacy-preserving recommender systems

paper_content:

Recommender Systems are used in various domains to generate personalized information based on personal user data. The ability to preserve the privacy of all participants is an essential requirement of the underlying Information Filtering architectures, because the deployed Recommender Systems have to be accepted by privacy-aware users as well as information and service providers. Existing approaches neglect to address privacy in this multilateral way. We have developed an approach for privacy-preserving Recommender Systems based on Multiagent System technology which enables applications to generate recommendations via various filtering techniques while preserving the privacy of all participants. We describe the main modules of our solution as well as an application we have implemented based on this approach.
---
paper_title: Privacy-preserving demographic filtering

paper_content:

The use of recommender systems in e-commerce to guide customer choices presents a privacy protection problem that is twofold. We seek to protect the privacy interests of customers by trying to keep private their identity and demographic characteristics, and possibly also their buying preferences and behaviour. This can be desirable even if anonymity is used. Furthermore, we want to protect the commercial interests of the e-commerce service providers by allowing them to make recommendations as accurate as possible, without unnecessarily revealing valuable information they have legitimately accumulated, such as market trends, to third parties.In this paper, we concentrate on recommender systems based on demographic filtering, which make recommendations based on feedback of previous users of similar demographic characteristics (such as age, sex, level of education, wealth, geographical location, etc.). We propose a system called ALAMBIC, which adequately achieves the above privacy-protection objectives in this kind of recommender systems. Our system is based on a semi-trusted third party in which the users need only have limited confidence. A main originality of our approach is to split user data between that party and the service provider in such a way that neither can derive sensitive information from their share alone.
---
paper_title: A Taxonomy of Privacy

paper_content:

Privacy is a concept in disarray. Nobody can articulate what it means. As one commentator has observed, privacy suffers from an embarrassment of meanings. Privacy is far too vague a concept to guide adjudication and lawmaking, as abstract incantations of the importance of privacy do not fare well when pitted against more concretely-stated countervailing interests. In 1960, the famous torts scholar William Prosser attempted to make sense of the landscape of privacy law by identifying four different interests. But Prosser focused only on tort law, and the law of information privacy is significantly more vast and complex, extending to Fourth Amendment law, the constitutional right to information privacy, evidentiary privileges, dozens of federal privacy statutes, and hundreds of state statutes. Moreover, Prosser wrote over 40 years ago, and new technologies have given rise to a panoply of new privacy harms. A new taxonomy to understand privacy violations is thus sorely needed. This article develops a taxonomy to identify privacy problems in a comprehensive and concrete manner. It endeavors to guide the law toward a more coherent understanding of privacy and to serve as a framework for the future development of the field of privacy law.
---
paper_title: Engineering Privacy

paper_content:

In this paper we integrate insights from diverse islands of research on electronic privacy to offer a holistic view of privacy engineering and a systematic structure for the discipline's topics. First we discuss privacy requirements grounded in both historic and contemporary perspectives on privacy. We use a three-layer model of user privacy concerns to relate them to system operations (data transfer, storage and processing) and examine their effects on user behavior. In the second part of the paper we develop guidelines for building privacy-friendly systems. We distinguish two approaches: "privacy-by-policy" and "privacy-by-architecture." The privacy-by-policy approach focuses on the implementation of the notice and choice principles of fair information practices (FIPs), while the privacy-by-architecture approach minimizes the collection of identifiable personal data and emphasizes anonymization and client-side data storage and processing. We discuss both approaches with a view to their technical overlaps and boundaries as well as to economic feasibility. The paper aims to introduce engineers and computer scientists to the privacy research domain and provide concrete guidance on how to design privacy-friendly systems.
---
paper_title: Anonymity and software agents: An interdisciplinary challenge

paper_content:

Software agents that play a role in E-commerce and E-government applications involving the Internet often contain information about the identity of their human user such as credit cards and bank accounts. This paper discusses whether this is necessary: whether human users and software agents are allowed to be anonymous under the relevant legal regimes and whether an adequate interaction and balance between law and anonymity can be realised from both the perspective of Computer Systems and the perspective of Law.
---
paper_title: Anonymity Metrics Revisited

paper_content:

In 2001, two information theoretic anonymity metrics were proposed: the "effective anonymity set size" and the "degree of anonymity". In this talk, we propose an abstract model for a general anonymity system which is consistent with the definition of anonymity on which the metrics are based. We revisit entropy-based anonymity metrics, and we apply them to Crowds, a practical ::: anonymity system. We discuss the differences between the two metrics ::: and the results obtained in the example.
---
paper_title: Analysis of Privacy Loss in Distributed Constraint Optimization

paper_content:

Distributed Constraint Optimization (DCOP) is rapidly emerging as a prominent technique for multi agent coordination. However, despite agent privacy being a key motivation for applying DCOPs in many applications, rigorous quantitative evaluations of privacy loss in DCOP algorithms have been lacking. Recently, [Maheswaran et al. 2005] introduced a framework for quantitative evaluations of privacy in DCOP algorithms, showing that some DCOP algorithms lose more privacy than purely centralized approaches and questioning the motivation for applying DCOPs. This paper addresses the question of whether state-of-the art DCOP algorithms suffer from a similar shortcoming by investigating several of the most efficient DCOP algorithms, including both DPOP and ADOPT. Furthermore, while previous work investigated the impact on efficiency of distributed contraint reasoning design decisions (e.g. constraint-graph topology, asynchrony, message-contents), this paper examines the privacy aspect of such decisions, providing an improved understanding of privacy-efficiency tradeoffs.
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paper_title: Privacy Loss in Distributed Constraint Reasoning: A Quantitative Framework for Analysis and its Applications

paper_content:

It is critical that agents deployed in real-world settings, such as businesses, offices, universities and research laboratories, protect their individual users' privacy when interacting with other entities. Indeed, privacy is recognized as a key motivating factor in the design of several multiagent algorithms, such as in distributed constraint reasoning (including both algorithms for distributed constraint optimization (DCOP) and distributed constraint satisfaction (DisCSPs)), and researchers have begun to propose metrics for analysis of privacy loss in such multiagent algorithms. Unfortunately, a general quantitative framework to compare these existing metrics for privacy loss or to identify dimensions along which to construct new metrics is currently lacking. This paper presents three key contributions to address this shortcoming. First, the paper presents VPS (Valuations of Possible States), a general quantitative framework to express, analyze and compare existing metrics of privacy loss. Based on a state-space model, VPS is shown to capture various existing measures of privacy created for specific domains of DisCSPs. The utility of VPS is further illustrated through analysis of privacy loss in DCOP algorithms, when such algorithms are used by personal assistant agents to schedule meetings among users. In addition, VPS helps identify dimensions along which to classify and construct new privacy metrics and it also supports their quantitative comparison. Second, the article presents key inference rules that may be used in analysis of privacy loss in DCOP algorithms under different assumptions. Third, detailed experiments based on the VPS-driven analysis lead to the following key results: (i) decentralization by itself does not provide superior protection of privacy in DisCSP/DCOP algorithms when compared with centralization; instead, privacy protection also requires the presence of uncertainty about agents' knowledge of the constraint graph. (ii) one needs to carefully examine the metrics chosen to measure privacy loss; the qualitative properties of privacy loss and hence the conclusions that can be drawn about an algorithm can vary widely based on the metric chosen. This paper should thus serve as a call to arms for further privacy research, particularly within the DisCSP/DCOP arena.
---
paper_title: Distributed constraint satisfaction and optimization with privacy enforcement

paper_content:

Several naturally distributed negotiation/cooperation problems with privacy requirements can be modeled within the distributed constraint satisfaction framework, where the constraints are secrets of the participants. Most of the existing techniques aim at various tradeoffs between complexity and privacy guarantees, while others aim to maximize privacy first, according to Yokoo et al. (2002), Silaghi (2003), Faltings (2003), Liu et al. (2002) and Wallace and Silaghi (2004). In Silaghi (2003) we introduced a first technique allowing agents to solve distributed constraint problems (DisCSPs), without revealing anything and without trusting each other or some server. The technique we propose now is a dm times improvement for m variables of domain size d. On the negative side, the fastest versions of the technique require storing of O(d/sup m/) big integers. From a practical point of view, we improve the privacy with which these problems can be solved, and improve the efficiency with which /spl lfloor/n-1/2/spl rfloor/-privacy can be achieved, while it remains inapplicable for larger problems. The technique of Silaghi (2003) has a simple extension to optimization for distributed weighted CSPs. However, that obvious extension leaks to everybody sensitive information concerning the quality of the computed solution. We found a way to avoid this leak, which constitutes another contribution of This work.
---
paper_title: SSDPOP: improving the privacy of DCOP with secret sharing

paper_content:

multiagent systems designed to work collaboratively with groups of people typically require private information that people will entrust to them only if they have assurance that this information will be protected. Although Distributed Constraint Optimization (DCOP) has emerged as a prominent technique for multiagent coordination, existing algorithms for solving DCOP problems do not adeqately protect agents' privacy. This paper analyzes privacy protection and loss in existing DCOP algorithms. It presents a new algorithm, SSDPOP, which augments a prominent DCOP algorithm (DPOP) with secret sharing techniques. This approach significantly reduces privacy loss, while preserving the structure of the DPOP algorithm and introducing only minimal computational overhead. Results show that SSDPOP reduces privacy loss by 29--88% on average over DPOP.
---
paper_title: Secure Distributed Constraint Satisfaction: Reaching Agreement without Revealing Private Information

paper_content:

This paper develops a secure distributed Constraint Satisfaction algorithm. A Distributed Constraint Satisfaction Problem (DisCSP) is a CSP in which variables and constraints are distributed among multiple agents. A major motivation for solving a DisCSP without gathering all information in one server is the concern about privacy/security. However, existing DisCSP algorithms leak some information during the search process and privacy/security issues are not dealt with formally. Our newly developed algorithm utilizes a public key encryption scheme. In this algorithm, multiple servers, which receive encrypted information from agents, cooperatively perform a search process that is equivalent to a standard chronological backtracking. This algorithm does not leak any private information, i.e., neither agents nor servers can obtain any additional information on the value assignment of variables that belong to other agents.
---
paper_title: Onion Routing for Anonymous and Private Internet Connections

paper_content:

Abstract : Preserving privacy means not only hiding the content of messages, but also hiding who is talking to whom (traffic analysis). Much like a physical envelope, the simple application of cryptography within a packet-switched network hides the messages being sent, but can reveal who is talking to whom, and how often. Onion Routing is a general purpose infrastructure for private communication over a public network [8, 9, 4]. It provides anonymous connections that are strongly resistant to both eavesdropping and traffic analysis. The connections are bidirectional, near real-time, and can be used for both connection-based and connectionless traffic. Onion Routing interfaces with off the shelf software and systems through specialized proxies, making it easy to integrate into existing systems. Prototypes have been running since July 1997. As of this article's publication, the prototype network is processing more than 1 million Web connections per month from more than six thousand IP addresses in twenty countries and in all six main top level domains. [7]
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paper_title: Anonymous Communications for Mobile Agents

paper_content:

Anonymous communication techniques are vital for some types of e-commerce applications. There have been several different approaches developed for providing anonymous communication over the Internet. In this paper, we review key techniques for anonymous communication and describe an alternate anonymous networking approach based on agile agents intended to provide anonymous communication protection for mobile agent systems.
---
paper_title: IntelliShopper: a proactive, personal, private shopping assistant

paper_content:

The IntelliShopper is a shopping assistant designed to empower consumers. It is a personal assistant in that it observes the users while shopping and learns their preferences with respect to various features that characterize shopping items. It is proactive in that it remembers the users' requests and autonomously monitors vendor sites for new items that might match the users' needs and preferences. Finally, it protects users' privacy by means of pseudonymity, IP anony\-mizing, and trusted filtering. Pseudonymity is achieved through the use of personae; we show that this approach also behooves successful classification. IP anonymizing can be performed in at least two manners, which we discuss and compare in the context of our application. Trusted filtering --- as opposed to merchant-based filtering --- improves privacy by allowing users to select their preferred privacy representative. This paper introduces the IntelliShopper system, discusses its architecture and components, describes a prototype implementation, and outlines preliminary evaluations of its performance.
---
paper_title: Untraceable electronic mail, return addresses, and digital pseudonyms

paper_content:

A technique based on public key cryptography is presented that allows an electronic mail system to hide who a participant communicates with as well as the content of the communication - in spite of an unsecured underlying telecommunication system. The technique does not require a universally trusted authority. One correspondent can remain anonymous to a second, while allowing the second to respond via an untraceable return address. The technique can also be used to form rosters of untraceable digital pseudonyms from selected applications. Applicants retain the exclusive ability to form digital signatures corresponding to their pseudonyms. Elections in which any interested party can verify that the ballots have been properly counted are possible if anonymously mailed ballots are signed with pseudonyms from a roster of registered voters. Another use allows an individual to correspond with a record-keeping organization under a unique pseudonym, which appears in a roster of acceptable clients.
---
paper_title: Tor: The Second-Generation Onion Router

paper_content:

We present Tor, a circuit-based low-latency anonymous communication service. This second-generation Onion Routing system addresses limitations in the original design by adding perfect forward secrecy, congestion control, directory servers, integrity checking, configurable exit policies, and a practical design for location-hidden services via rendezvous points. Tor works on the real-world Internet, requires no special privileges or kernel modifications, requires little synchronization or coordination between nodes, and provides a reasonable tradeoff between anonymity, usability, and efficiency. We briefly describe our experiences with an international network of more than 30 nodes. We close with a list of open problems in anonymous communication.
---
paper_title: Design and Implementation of a Secure Multi-Agent Marketplace

paper_content:

A multi-agent marketplace, MAGNET (Multi AGent Negotiation Testbed), is a promising solution for conducting online combinatorial auctions. The trust model of MAGNET is somewhat dieren t from other on-line auction systems, since the marketplace, which mediates all communications between agents, acts as a partiallytrusted third party. In this paper, we identify the security vulnerabilities of MAGNET and present a solution that overcomes these weaknesses. Our solution makes use of three dieren t existing technologies with standard cryptographic techniques: a publish/subscribe system to provide simple and general messaging, time-release cryptography to provide guaranteed nondisclosure of the bids, and anonymous communication to hide the identity of the bidders until the end of the auction. By doing so, we successfully minimize the trust on the market as well as increase the security of the whole system. The protocol that we have developed can be adapted for use by other agent-based auction systems, which use a third party to mediate transactions.
---
paper_title: Security without identification: transaction systems to make big brother obsolete

paper_content:

The large-scale automated transaction systems of the near future can be designed to protect the privacy and maintain the security of both individuals and organizations.
---
paper_title: User centricity: a taxonomy and open issues

paper_content:

User centricity is a significant concept in federated identity management (FIM), as it provides for stronger user control and privacy. However, several notions of user-centricity in the FIM community render its semantics unclear and hamper future research in this area. Therefore, we consider user-centricity abstractly and establish a comprehensive taxonomy encompassing user-control, architecture, and usability aspects of user-centric FIM. On the systems layer, we discuss user-centric FIM systems and classify them into two predominant variants with significant feature sets. We distinguish credential-focused systems, which advocate offline identity providers and long-term credentials at a user's client, and relationship-focused systems, which rely on the relationships between users and online identity providers that create short-term credentials during transactions. Note that these two notions of credentials are quite different. The further one encompasses cryptographic credentials as defined by Lysyanskaya et al. [30], the latter one federation tokens as used in today's FIM protocols like Liberty.We raise the question where user-centric FIM systems may go--within the limitations of the user-centricity paradigm as well as beyond them. Firstly, we investigate the existence of a universal user-centric FIM system that can achieve a superset of security and privacy properties as well as the characteristic features of both pre-dominant classes. Secondly, we explore the feasibility of reaching beyond user-centricity, that is, allowing a user of a user-centric FIM system to again give away user-control by means of an explicit act of delegation. We do neither claim a solution for universal user-centric systems nor for the extension beyond the boundaries ventures by leveraging the properties of a credential-focused FIM system.
---
paper_title: IntelliShopper: a proactive, personal, private shopping assistant

paper_content:

The IntelliShopper is a shopping assistant designed to empower consumers. It is a personal assistant in that it observes the users while shopping and learns their preferences with respect to various features that characterize shopping items. It is proactive in that it remembers the users' requests and autonomously monitors vendor sites for new items that might match the users' needs and preferences. Finally, it protects users' privacy by means of pseudonymity, IP anony\-mizing, and trusted filtering. Pseudonymity is achieved through the use of personae; we show that this approach also behooves successful classification. IP anonymizing can be performed in at least two manners, which we discuss and compare in the context of our application. Trusted filtering --- as opposed to merchant-based filtering --- improves privacy by allowing users to select their preferred privacy representative. This paper introduces the IntelliShopper system, discusses its architecture and components, describes a prototype implementation, and outlines preliminary evaluations of its performance.
---
paper_title: An agent-based approach for privacy-preserving recommender systems

paper_content:

Recommender Systems are used in various domains to generate personalized information based on personal user data. The ability to preserve the privacy of all participants is an essential requirement of the underlying Information Filtering architectures, because the deployed Recommender Systems have to be accepted by privacy-aware users as well as information and service providers. Existing approaches neglect to address privacy in this multilateral way. We have developed an approach for privacy-preserving Recommender Systems based on Multiagent System technology which enables applications to generate recommendations via various filtering techniques while preserving the privacy of all participants. We describe the main modules of our solution as well as an application we have implemented based on this approach.
---
paper_title: Privacy-preserving demographic filtering

paper_content:

The use of recommender systems in e-commerce to guide customer choices presents a privacy protection problem that is twofold. We seek to protect the privacy interests of customers by trying to keep private their identity and demographic characteristics, and possibly also their buying preferences and behaviour. This can be desirable even if anonymity is used. Furthermore, we want to protect the commercial interests of the e-commerce service providers by allowing them to make recommendations as accurate as possible, without unnecessarily revealing valuable information they have legitimately accumulated, such as market trends, to third parties.In this paper, we concentrate on recommender systems based on demographic filtering, which make recommendations based on feedback of previous users of similar demographic characteristics (such as age, sex, level of education, wealth, geographical location, etc.). We propose a system called ALAMBIC, which adequately achieves the above privacy-protection objectives in this kind of recommender systems. Our system is based on a semi-trusted third party in which the users need only have limited confidence. A main originality of our approach is to split user data between that party and the service provider in such a way that neither can derive sensitive information from their share alone.
---
paper_title: Enforcing security in the AgentScape middleware

paper_content:

Multi Agent Systems (MAS) provide a useful paradigm for accessing distributed resources in an autonomic and self-directed manner. Resources, such as web services, are increasingly becoming available in large distributed environments. Currently, numerous multi agent systems are available. However, for the multi agent paradigm to become a genuine mainstream success certain key features need to be addressed: the foremost being security. While security has been a focus of the MAS community, configuring and managing such multi agent systems typically remains non-trivial. Well defined and easily configurable security policies address this issue. A security architecture that is both flexible and featureful is prerequisite for a MAS. A novel security policy enforcement system for multi agent middleware systems is introduced. The system facilitates a set of good default configurations but also allows extensive scope for users to develop customised policies to suit their individual needs. An agent middleware, AgentScape, is used to illustrate the system.
---
paper_title: Partial identities as a foundation for trust and reputation

paper_content:

This paper explores the relationships between the hard security concepts of identity and privacy on the one hand, and the soft security concepts of trust and reputation on the other hand. We specifically focus on two vulnerabilities that current trust and reputation systems have: the change of identity and multiple identities problems. As a result, we provide a privacy preserving solution to these vulnerabilities which integrates the explored relationships among identity, privacy, trust and reputation. We also provide a prototype of our solution to these vulnerabilities and an application scenario.
---
paper_title: Privacy-enhancing technologies: approaches and development

paper_content:

In this paper, we discuss privacy threats on the Internet and possible solutions to this problem. Examples of privacy threats in the communication networks are identity disclosure, linking data traffic with identity, location disclosure in connection with data content transfer, user profile disclosure or data disclosure itself. Identifying the threats and the technology that may be used for protection can provide satisfactory protection of privacy over general networks that are building today the information infrastructure. In general, these technologies are known as Privacy-Enhancing Technologies (PETs). This article analyses some of the key privacy-Enhancing Technologies and provides view in the on-going projects developing these technologies.
---
paper_title: An agent infrastructure for privacy-enhancing agent-based e-commerce applications

paper_content:

Privacy is of crucial importance in order for agent-based e-commerce applications to be of broad use. Privacy can be enhanced minimizing data identifiability, i.e., the degree by which personal information can be directly attributed to a particular individual. However, minimizing data identifiability may directly impact other crucial issues in agent-based e-commerce, such as accountability, trust, and reputation. In this paper, we present an agent infrastructure for agent-based e-commerce applications. This agent infrastructure enhances privacy without compromising accountability, trust, and reputation.
---
paper_title: A group-oriented secure multiagent platform

paper_content:

Security is becoming a major concern in multiagent systems, since an agent's incorrect or inappropriate behaviour may cause non-desired effects, such as money and data loss. Some multiagent platforms (MAP) are now providing baseline security features, such as authentication, authorization, integrity and confidentiality. However, they fail to support other features related to the sociability skills of agents such as agent groups. What is more, none of the listed MAPs provide a mechanism for preserving the privacy of the users (regarding their identities) that run their agents on such MAPs. In this paper, we present the security infrastructure (SI) of the Magentix MAP, which supports agent groups and preserves user identity privacy. The SI is based on identities that are assigned to all the different entities found in Magentix (users, agents and agent groups). We also provide an evaluation of the SI describing an example application built on top of Magentix and a performance evaluation of it. Copyright © 2010 John Wiley & Sons, Ltd.
---
paper_title: Network Security Essentials: Applications and Standards

paper_content:

From the Book: ::: PREFACE: Preface In this age of electronic connectivity, of viruses and hackers, of electronic eavesdropping and electronic fraud, network security has assumed increasing importance. Two trends have come together to make the topic of this book of vital interest. First, the explosive growth in computer systems and their interconnections via networks has increased the dependence of both organizations and individuals on the information stored and communicated using these systems. This, in turn, has led to a heightened awareness of the need to protect data and resources from disclosure, to guarantee the authenticity of data and messages, and to protect systems from network-based attacks. Second, the disciplines of cryptography and network security have matured, leading to the development of practical, readily available applications to enforce network security. Objectives It is the purpose of this book to provide a practical survey of network security applications and standards. The emphasis is on applications that are widely used on the Internet and for corporate networks, and on standards, especially Internet standards, that have been widely deployed. Intended Audience The book is intended for both an academic and a professional audience. As a textbook, it is intended as a one-semester undergraduate course on network security for computer science, computer engineering, and electrical engineering majors. The book also serves as a basic reference volume and is suitable for self-study. Plan of the Book The book is organized in three parts: I. Cryptography: A concise survey of the cryptographic algorithms and protocols i reportunderlyingnetwork security applications, including encryption, hash functions, digital signatures, and key exchange. i See Appen~ II. Network Security Applications: Covers important network security tools and applications, including Kerberos, X.509v3 certificates, PGP, S/MIME, IP Secu- rity, SSL/TLS, SET, and SNMPv3. III. System Security: Looks at system-level security issues, including the threat of and countermeasures for intruders and viruses, and the use of firewalls and trusted systems. This book i A more detailed, chapter-by-chapter summary appears at the end of Chapter ~ (CNS2e). 1. In addition, the book includes an extensive glossary, a list of frequently used detailed an< acronyms, and a bibliography. There are also end-of-chapter problems and sugges- of which co tions for further reading. dards (NSE 3. NSE1e in covers SNh Internet Services for Instructors and Students There is a Web page for this book that provides support for students and instruc tors. The page includes links to relevant sites, transparency masters of figures in the book in PDF (Adobe Acrobat) format, and sign-up information for the book's Internet mailing list. The Web page is at ...
---
paper_title: Enforcing security in the AgentScape middleware

paper_content:

Multi Agent Systems (MAS) provide a useful paradigm for accessing distributed resources in an autonomic and self-directed manner. Resources, such as web services, are increasingly becoming available in large distributed environments. Currently, numerous multi agent systems are available. However, for the multi agent paradigm to become a genuine mainstream success certain key features need to be addressed: the foremost being security. While security has been a focus of the MAS community, configuring and managing such multi agent systems typically remains non-trivial. Well defined and easily configurable security policies address this issue. A security architecture that is both flexible and featureful is prerequisite for a MAS. A novel security policy enforcement system for multi agent middleware systems is introduced. The system facilitates a set of good default configurations but also allows extensive scope for users to develop customised policies to suit their individual needs. An agent middleware, AgentScape, is used to illustrate the system.
---
paper_title: Partial identities as a foundation for trust and reputation

paper_content:

This paper explores the relationships between the hard security concepts of identity and privacy on the one hand, and the soft security concepts of trust and reputation on the other hand. We specifically focus on two vulnerabilities that current trust and reputation systems have: the change of identity and multiple identities problems. As a result, we provide a privacy preserving solution to these vulnerabilities which integrates the explored relationships among identity, privacy, trust and reputation. We also provide a prototype of our solution to these vulnerabilities and an application scenario.
---
paper_title: Authentication for Humans

paper_content:

To authenticate something in the Internet is to verify that its identity is as claimed. Unless the identity itself is meaningful and the user is presented with evidence to support the claim of identity there can be no authentication. Many ef- forts to implement authentication seem to forget this and only focus on the cryp- tographic authentication mechanisms. We describe what is needed in addition to cryptography for authentication to be meaningful to humans, and illustrates this by showing how it can be applied in the Web and WAP architectures.
---
paper_title: User centricity: a taxonomy and open issues

paper_content:

User centricity is a significant concept in federated identity management (FIM), as it provides for stronger user control and privacy. However, several notions of user-centricity in the FIM community render its semantics unclear and hamper future research in this area. Therefore, we consider user-centricity abstractly and establish a comprehensive taxonomy encompassing user-control, architecture, and usability aspects of user-centric FIM. On the systems layer, we discuss user-centric FIM systems and classify them into two predominant variants with significant feature sets. We distinguish credential-focused systems, which advocate offline identity providers and long-term credentials at a user's client, and relationship-focused systems, which rely on the relationships between users and online identity providers that create short-term credentials during transactions. Note that these two notions of credentials are quite different. The further one encompasses cryptographic credentials as defined by Lysyanskaya et al. [30], the latter one federation tokens as used in today's FIM protocols like Liberty.We raise the question where user-centric FIM systems may go--within the limitations of the user-centricity paradigm as well as beyond them. Firstly, we investigate the existence of a universal user-centric FIM system that can achieve a superset of security and privacy properties as well as the characteristic features of both pre-dominant classes. Secondly, we explore the feasibility of reaching beyond user-centricity, that is, allowing a user of a user-centric FIM system to again give away user-control by means of an explicit act of delegation. We do neither claim a solution for universal user-centric systems nor for the extension beyond the boundaries ventures by leveraging the properties of a credential-focused FIM system.
---
paper_title: A group-oriented secure multiagent platform

paper_content:

Security is becoming a major concern in multiagent systems, since an agent's incorrect or inappropriate behaviour may cause non-desired effects, such as money and data loss. Some multiagent platforms (MAP) are now providing baseline security features, such as authentication, authorization, integrity and confidentiality. However, they fail to support other features related to the sociability skills of agents such as agent groups. What is more, none of the listed MAPs provide a mechanism for preserving the privacy of the users (regarding their identities) that run their agents on such MAPs. In this paper, we present the security infrastructure (SI) of the Magentix MAP, which supports agent groups and preserves user identity privacy. The SI is based on identities that are assigned to all the different entities found in Magentix (users, agents and agent groups). We also provide an evaluation of the SI describing an example application built on top of Magentix and a performance evaluation of it. Copyright © 2010 John Wiley & Sons, Ltd.
---
paper_title: On agent technology for e-commerce: trust, security and legal issues

paper_content:

The vision of future electronic marketplaces (e-markets) is that of markets being populated by autonomous intelligent entities—software, trading, e-agents—representing their users or owners and conducting business on their behalf. For this vision to materialize, one fundamental issue that needs to be addressed is that of trust. First, users need to be able to trust that the agents will do what they say they do. Second, they need to be confident that their privacy is protected and that the security risks involved in entrusting agents to perform transactions on their behalf are minimized. Finally, users need to be assured that any legal issues relating to agents trading electronically are fully covered as they are in traditional trading practices. In this paper we consider the barriers for the adoption of agent technology in electronic commerce (e-commerce) which pertain to trust, security and legal issues. We discuss the perceived risks of the use of agents in e-commerce and the fundamental issue of trust in this context. Issues regarding security, and how some of these can be addressed through the use of cryptography, are described. The impact of the use of agent technology on the users' privacy and how it can be both protected as well as hindered by it is also examined. Finally, we discuss the legal issues that arise in agent-mediated e-commerce and discuss the idea of attributing to software agents the status of legal persons or e-persons and the various implications.
---
paper_title: Review on Computational Trust and Reputation Models

paper_content:

The scientific research in the area of computational mechanisms for trust and reputation in virtual societies is a recent discipline oriented to increase the reliability and performance of electronic communities. Computer science has moved from the paradigm of isolated machines to the paradigm of networks and distributed computing. Likewise, artificial intelligence is quickly moving from the paradigm of isolated and non-situated intelligence to the paradigm of situated, social and collective intelligence. The new paradigm of the so called intelligent or autonomous agents and multi-agent systems (MAS) together with the spectacular emergence of the information society technologies (specially reflected by the popularization of electronic commerce) are responsible for the increasing interest on trust and reputation mechanisms applied to electronic societies. This review wants to offer a panoramic view on current computational trust and reputation models.
---
paper_title: A Survey of Trust and Reputation Systems for Online Service Provision

paper_content:

Trust and reputation systems represent a significant trend in decision support for Internet mediated service provision. The basic idea is to let parties rate each other, for example after the completion of a transaction, and use the aggregated ratings about a given party to derive a trust or reputation score, which can assist other parties in deciding whether or not to transact with that party in the future. A natural side effect is that it also provides an incentive for good behaviour, and therefore tends to have a positive effect on market quality. Reputation systems can be called collaborative sanctioning systems to reflect their collaborative nature, and are related to collaborative filtering systems. Reputation systems are already being used in successful commercial online applications. There is also a rapidly growing literature around trust and reputation systems, but unfortunately this activity is not very coherent. The purpose of this article is to give an overview of existing and proposed systems that can be used to derive measures of trust and reputation for Internet transactions, to analyse the current trends and developments in this area, and to propose a research agenda for trust and reputation systems.
---
paper_title: Challenges for Robust Trust and Reputation Systems

paper_content:

The purpose of trust and reputation systems is to strengthen the quality of markets and communities by providing an incentive for good behaviour and quality services, and by sanctioning bad behaviour and low quality services. However, trust and reputation systems will only be able to produce this effect when they are sufficiently robust against strategic manipulation or direct attacks. Currently, robustness analysis of TRSs is mostly done through simple simulated scenarios implemented by the TRS designers themselves, and this can not be considered as reliable evidence for how these systems would perform in a realistic environment. In order to set robustness requirements it is important to know how important robustness really is in a particular community or market. This paper discusses research challenges for trust and reputation systems, and proposes a research agenda for developing sound and reliable robustness principles and mechanisms for trust and reputation systems.
---
paper_title: SybilGuard: defending against sybil attacks via social networks

paper_content:

Peer-to-peer and other decentralized, distributed systems are known to be particularly vulnerable to sybil attacks. In a sybil attack, a malicious user obtains multiple fake identities and pretends to be multiple, distinct nodes in the system. By controlling a large fraction of the nodes in the system, the malicious user is able to ldquoout voterdquo the honest users in collaborative tasks such as Byzantine failure defenses. This paper presents SybilGuard, a novel protocol for limiting the corruptive influences of sybil attacks. Our protocol is based on the ldquosocial networkrdquo among user identities, where an edge between two identities indicates a human-established trust relationship. Malicious users can create many identities but few trust relationships. Thus, there is a disproportionately small ldquocutrdquo in the graph between the sybil nodes and the honest nodes. SybilGuard exploits this property to bound the number of identities a malicious user can create. We show the effectiveness of SybilGuard both analytically and experimentally.
---
paper_title: Partial identities as a foundation for trust and reputation

paper_content:

This paper explores the relationships between the hard security concepts of identity and privacy on the one hand, and the soft security concepts of trust and reputation on the other hand. We specifically focus on two vulnerabilities that current trust and reputation systems have: the change of identity and multiple identities problems. As a result, we provide a privacy preserving solution to these vulnerabilities which integrates the explored relationships among identity, privacy, trust and reputation. We also provide a prototype of our solution to these vulnerabilities and an application scenario.
---
paper_title: Smart cheaters do prosper: Defeating trust and reputation systems

paper_content:

Traders in electronic marketplaces may behave dishonestly, cheating other agents. A multitude of trust and reputation systems have been proposed to try to cope with the problem of cheating. These systems are often evaluated by measuring their performance against simple agents that cheat randomly. Unfortunately, these systems are not often evaluated from the perspective of security---can a motivated attacker defeat the protection? Previously, it was argued that existing systems may suffer from vulnerabilities that permit effective, profitable cheating despite the use of the system. In this work, we experimentally substantiate the presence of these vulnerabilities by successfully implementing and testing a number of such 'attacks', which consist only of sequences of sales (honest and dishonest) that can be executed in the system. This investigation also reveals two new, previously-unnoted cheating techniques. Our success in executing these attacks compellingly makes a key point: security must be a central design goal for developers of trust and reputation systems.
---
paper_title: The Social Cost of Cheap Pseudonyms

paper_content:

We consider the problems of societal norms for cooperation and reputation when it is possible to obtain cheap pseudonyms, something that is becoming quite common in a wide variety of interactions on the Internet. This introduces opportunities to misbehave without paying reputational consequences. A large degree of cooperation can still emerge, through a convention in which newcomers "pay their dues" by accepting poor treatment from players who have established positive reputations. One might hope for an open society where newcomers are treated well, but there is an inherent social cost in making the spread of reputations optional. We prove that no equilibrium can sustain significantly more cooperation than the dues-paying equilibrium in a repeated random matching game with a large number of players in which players have finite lives and the ability to change their identities, and there is a small but nonvanishing probability of mistakes. Although one could remove the inefficiency of mistreating newcomers by disallowing anonymity, this is not practical or desirable in a wide variety of transactions. We discuss the use of entry fees, which permits newcomers to be trusted but excludes some players with low payoffs, thus introducing a different inefficiency. We also discuss the use of free but unreplaceable pseudonyms, and describe a mechanism that implements them using standard encryption techniques, which could be practically implemented in electronic transactions. Copyright (c) 2001 Massachusetts Institute of Technology.
---
paper_title: Trust in multi-agent systems

paper_content:

Trust is a fundamental concern in large-scale open distributed systems. It lies at the core of all interactions between the entities that have to operate in such uncertain and constantly changing environments. Given this complexity, these components, and the ensuing system, are increasingly being conceptualised, designed, and built using agent-based techniques and, to this end, this paper examines the specific role of trust in multi-agent systems. In particular, we survey the state of the art and provide an account of the main directions along which research efforts are being focused. In so doing, we critically evaluate the relative strengths and weaknesses of the main models that have been proposed and show how, fundamentally, they all seek to minimise the uncertainty in interactions. Finally, we outline the areas that require further research in order to develop a comprehensive treatment of trust in complex computational settings.
---
paper_title: Sybilproof reputation mechanisms

paper_content:

Due to the open, anonymous nature of many P2P networks, new identities - or sybils - may be created cheaply and in large numbers. Given a reputation system, a peer may attempt to falsely raise its reputation by creating fake links between its sybils. Many existing reputation mechanisms are not resistant to these types of strategies.Using a static graph formulation of reputation, we attempt to formalize the notion of sybilproofness. We show that there is no symmetric sybilproof reputation function. For nonsymmetric reputations, following the notion of reputation propagation along paths, we give a general asymmetric reputation function based on flow and give conditions for sybilproofness.
---
paper_title: A survey of attack and defense techniques for reputation systems

paper_content:

Reputation systems provide mechanisms to produce a metric encapsulating reputation for a given domain for each identity within the system. These systems seek to generate an accurate assessment in the face of various factors including but not limited to unprecedented community size and potentially adversarial environments. We focus on attacks and defense mechanisms in reputation systems. We present an analysis framework that allows for the general decomposition of existing reputation systems. We classify attacks against reputation systems by identifying which system components and design choices are the targets of attacks. We survey defense mechanisms employed by existing reputation systems. Finally, we analyze several landmark systems in the peer-to-peer domain, characterizing their individual strengths and weaknesses. Our work contributes to understanding (1) which design components of reputation systems are most vulnerable, (2) what are the most appropriate defense mechanisms and (3) how these defense mechanisms can be integrated into existing or future reputation systems to make them resilient to attacks.
---
paper_title: Review on Computational Trust and Reputation Models

paper_content:

The scientific research in the area of computational mechanisms for trust and reputation in virtual societies is a recent discipline oriented to increase the reliability and performance of electronic communities. Computer science has moved from the paradigm of isolated machines to the paradigm of networks and distributed computing. Likewise, artificial intelligence is quickly moving from the paradigm of isolated and non-situated intelligence to the paradigm of situated, social and collective intelligence. The new paradigm of the so called intelligent or autonomous agents and multi-agent systems (MAS) together with the spectacular emergence of the information society technologies (specially reflected by the popularization of electronic commerce) are responsible for the increasing interest on trust and reputation mechanisms applied to electronic societies. This review wants to offer a panoramic view on current computational trust and reputation models.
---
paper_title: Trust in multi-agent systems

paper_content:

Trust is a fundamental concern in large-scale open distributed systems. It lies at the core of all interactions between the entities that have to operate in such uncertain and constantly changing environments. Given this complexity, these components, and the ensuing system, are increasingly being conceptualised, designed, and built using agent-based techniques and, to this end, this paper examines the specific role of trust in multi-agent systems. In particular, we survey the state of the art and provide an account of the main directions along which research efforts are being focused. In so doing, we critically evaluate the relative strengths and weaknesses of the main models that have been proposed and show how, fundamentally, they all seek to minimise the uncertainty in interactions. Finally, we outline the areas that require further research in order to develop a comprehensive treatment of trust in complex computational settings.
---
paper_title: Privacy and contextual integrity: framework and applications

paper_content:

Contextual integrity is a conceptual framework for understanding privacy expectations and their implications developed in the literature on law, public policy, and political philosophy. We formalize some aspects of contextual integrity in a logical framework for expressing and reasoning about norms of transmission of personal information. In comparison with access control and privacy policy frameworks such as RBAC, EPAL, and P3P, these norms focus on who personal information is about, how it is transmitted, and past and future actions by both the subject and the users of the information. Norms can be positive or negative depending on whether they refer to actions that are allowed or disallowed. Our model is expressive enough to capture naturally many notions of privacy found in legislation, including those found in HIPAA, COPPA, and GLBA. A number of important problems regarding compliance with privacy norms, future requirements associated with specific actions, and relations between policies and legal standards reduce to standard decision procedures for temporal logic.
---
paper_title: Open issues for normative multi-agent systems

paper_content:

A challenging problem currently addressed in the multi-agent systems area is the development of open systems; which are characterized by the heterogeneity of their participants and the dynamic features of both their participants and their environment. The main feature of agents in these systems is autonomy. It is this autonomy that requires regulation, and norms are a solution for this. Norms represent a tool for achieving coordination and cooperation among the members of a society. They have been employed in the field of Artificial Intelligence as a formal specification of deontic statements aimed at regulating the actions of software agents and the interactions among them. This article gives an overview of the most relevant works on norms for multi-agent systems. This review considers open multi-agent systems challenges and points out the main open questions that remain in norm representation, reasoning, creation, and implementation.
---
paper_title: Introduction to Normative Multiagent Systems

paper_content:

In this paper we use recursive modelling to formalize sanction-based obligations in a qualitative game theory. In particular, we formalize an agent who attributes mental attitudes such as goals and desires to the normative system which creates and enforces its obligations. The wishes (goals, desires) of the normative system are the commands (obligations) of the agent. Since the agent is able to reason about the normative system’s behavior, our model accounts for many ways in which an agent can violate a norm believing that it will not be sanctioned. The theory can be used in theories or applications that need a model of rational decision making in normative multiagent systems, such as for example theories of fraud and deception, trust dynamics and reputation, electronic commerce, and virtual communities.
---
paper_title: Agent Technology for e-Commerce

paper_content:

List of Figures. List of Tables. Preface. 1 Introduction. 1.1 A paradigm shift. 1.2 Electronic commerce. 1.3 Agents and e-commerce. 1.4 Further reading. 1.5 Exercises and topics for discussion. 2 Software agents. 2.1 Characteristics of agents. 2.2 Agents as intentional systems. 2.3 Making decisions. 2.4 Planning. 2.5 Learning. 2.6 Agent architectures. 2.7 Agents in perspective. 2.8 Methodologies and languages. 2.9 Further reading. 2.10 Exercises and topics for discussion. 3 Multi-agent systems. 3.1 Characteristics of multi-agent systems. 3.2 Interaction. 3.3 Agent communication. 3.4 Ontologies. 3.5 Cooperative problem solving. 3.6 Virtual organisations as multi-agent systems. 3.7 Infrastructure requirements for open multi-agent systems. 3.8 Further reading. 3.9 Exercises and topics for discussion. 4 Shopping Agents. 4.1 Consumer buying behaviour model. 4.2 Comparison shopping. 4.3 Working for the user. 4.4 How shopping agents work. 4.5 Limitations and issues. 4.6 Further reading. 4.7 Exercises and topics for discussion. 5 Middle agents. 5.1 Matching. 5.2 Classification of middle agents. 5.3 Describing capabilities. 5.4 LARKS. 5.5 OWL-S. 5.6 Further reading. 5.7 Exercises and topics for discussion. 6 Recommender systems. 6.1 Information needed. 6.2 Providing recommendations. 6.3 Recommendation technologies. 6.4 Content-based filtering. 6.5 Collaborative filtering. 6.6 Combining content and collaborative filtering. 6.7 Recommender systems in e-commerce. 6.8 A note on personalization. 6.9 Further reading. 6.10 Exercises and topics for discussion. 7 Elements of strategic interaction. 7.1 Elements of Economics. 7.2 Elements of Game Theory. 7.3 Further reading. 7.4 Exercises and topics for discussion. 8 Negotiation I. 8.1 Negotiation protocols. 8.2 Desired properties of negotiation protocols. 8.3 Abstract architecture for negotiating agents. 8.4 Auctions. 8.5 Classification of auctions. 8.6 Basic auction formats. 8.7 Double auctions. 8.8 Multi-attribute auctions. 8.9 Combinatorial auctions. 8.10 Auction platforms. 8.11 Issues in practical auction design. 8.12 Further reading. 8.13 Exercises and topics for discussion. 9 Negotiation II. 9.1 Bargaining. 9.2 Negotiation in different domains. 9.3 Coalitions. 9.4 Applications of coalition formation. 9.5 Social choice problems. 9.6 Argumentation. 9.7 Further reading. 9.8 Exercises and topics for discussion. 10 Mechanism design. 10.1 The mechanism design problem. 10.2 Dominant strategy implementation. 10.3 The Gibbard-Satterthwaite Impossibility Theorem. 10.4 The Groves-Clarke mechanisms. 10.5 Mechanism design and computational issues. 10.6 Further reading. 10.7 Exercises and topics for discussion. 11 Mobile agents. 11.1 Introducing mobility. 11.2 Facilitating mobility. 11.3 Mobile agent systems. 11.4 Aglets. 11.5 Mobile agent security. 11.6 Issues on mobile agents. 11.7 Further reading. 11.8 Exercises and topics for discussion. 12 Trust, security and legal issues. 12.1 Perceived risks. 12.2 Trust. 12.3 Trust in e-commerce. 12.4 Electronic institutions. 12.5 Reputation systems. 12.6 Security. 12.7 Cryptography. 12.8 Privacy, anonymity and agents. 12.9 Agents and the law. 12.10 Agents as legal persons. 12.11 Closing remarks. 12.12 Further reading. 12.13 Exercises and topics for discussion. A Introduction to decision theory. A.2 Making decisions. A.3 Utilities. A.4 Further reading. Bibliography. Index.
---
paper_title: Specifying standard security mechanisms in multi-agent systems

paper_content:

Distributed multi-agent systems propose new infrastructure solutions to support the interoperability of electronic services. Security is a central issue for such infrastructures and is compounded by their intrinsic openness, heterogeneity and because of the autonomous and potentially self-interested nature of the agents therein. This article reviews the work that the FIPA agent standards body has undertaken to specify security in multi-agent systems. This enables a discussion about the main issues that developers have to face at different levels (i.e., intra-platform, inter-platform and application level) when developing agent-based security solutions in various domains.
---
paper_title: Privacy enhancing identity management: protection against re-identification and profiling

paper_content:

User centric identity management will be necessary to protect user's privacy in an electronic society. However, designing such systems is a complex task, as the expectations of the different parties involved in electronic transactions have to be met. In this work we give an overview on the actual situation in user centric identity management and point out problems encountered there. Especially we present the current state of research and mechanisms useful to protect the user's privacy. Additionally we show security problems that have to be borne in mind while designing such a system and point out possible solutions. Thereby, we concentrate on attacks on linkability and identifiability, and possible protection methods.
---
paper_title: Privacy and Identity Management

paper_content:

Creating and managing individual identities is a central challenge of the digital age. As identity management systems defined here as programs or frameworks that administer the collection, authentication, or use of identity and information linked to identity are implemented in both the public and private sectors, individuals are required to identify themselves with increasing frequency. Traditional identity management systems are run by organizations that control all mechanisms for authentication (establishing confidence in an identity claim's truth) and authorization (deciding what an individual should be allowed to do), as well as any behind-the-scenes profiling or scoring of individuals. Recent work has looked toward more user-centric models that attempt to put individuals in charge of when, where, how, and to whom they disclose their personal information.
---
paper_title: The Wiki Way: Quick Collaboration on the Web

paper_content:

Foreword. Preface. Why This Book? Why You Want to Read This. Book Structure. The Authors. Contributors and Colleagues. Errata and Omissions. Contacting Us. Read the Book, Use the Wiki! I. FROM CONCEPTS TO USING WIKI. 1. Introduction to Discussion and Collaboration Servers. In this Chapter. Collaboration and Discussion Tools. Collaboration Models. Who Uses Collaborative Discussion Servers? Whatever For? Features of a Web-Based Collaboration. On the Horizon: WebDAV. Comparing Wiki to Other Collaboration Tools. 2. What's a "Wiki"? The Wiki Concept. The Essence of Wiki. The User Experience. Usefulness Criteria. Wiki Basics. Wiki Clones. Wiki Implementations by Language. Other Wiki Offerings. Non-Wiki Servers. Wiki Application. Pros and Cons of a Wiki-Style Server. Why Consider Setting Up a Wiki? Other Issues. 3. Installing Wiki. QuickiWiki--Instant Serve. Installing Perl. Installing QuickiWiki. Multiple Instances. Wiki and Webserver. Wiki on IIS or PWS. The Apache Webserver. Installing Apache. Reconfiguring Apache. Testing Webserver Wiki. Wrapper Scripts. General Security Issues. Security and Database Integrity. Server Vulnerabilities. Addressing wiki Vulnerabilities. Configuring Your Browser Client. Fonts, Size and Layout. 4. Using Wiki. In this Chapter. Quicki Quick-Start. A Virtual Notebook. Making Wiki Notes, A Walkthrough. Wiki as PIM. A Working Example. The Content Model. Internal and External Hyperlink Models. Browsing Pages. Editing Pages. The Browser Editing Model. Building Wiki Content. Editing and Markup Conventions. 5. Structuring Wiki Content. In this Chapter. Wiki Structure. Structure Types. Only a Click Away. How Hard to Try. When to Impose Structure. When Not to Impose Structure. What is the Purpose of the Wiki? Structure Patterns. When to Spin Off New Wiki Servers. II. UNDERSTANDING THE HACKS. 6. Customizing Your Wiki. In this Chapter. Hacking Your Wiki Source. Copyright and Open Source License Policy. Why Customize? What to Customize. 7. Wiki Components Examined. In this Chapter. Dissecting QuickiWiki. QuickiWiki Component Model. Core QuickiWiki Modules. Sever Component. Optional Extended Components. Analyzing Page Content. Managing User Access. 8. Alternatives and Extensions. Parsing the Requests. ClusterWiki Component Model. The Library Module. Special Features. Spell Checking. Uploading Files. A Standard Wiki? 9. Wiki Administration and Tools. In this Chapter. Events History. Tracking Page Edits. Usage Statistics. Abuse Management. Access Management. Permission Models. Adding Authentication and Authorization. Administering the Database. Page Conversions. Page Management. Backup Issues. Server Resources and Wiki Loading. Avoiding User Waits. Implementing Wiki Constraints. Debugging a Wiki. Programming Resources. Backups. Low-Tech Debugging. Higher-Level Debugging. III. IMAGINE THE POSSIBILITIES. 10. Insights and Other Voices. In this Chapter. Wiki Culture. Wiki as Open Community. Writing Style Contention. Why Wiki Works. The Open-Edit Issue. When Wiki Doesn't Work. Public Wiki Issues. Wiki Style Guidelines. Notifying About Update. Design and Portability. Wiki Trade-Offs. Portability. The Future of Wiki. 11. Wiki Goes Edu. In this Chapter. CoWeb at Georgia Tech. Introduction to CoWeb. CoWeb Usage. Supported CoWeb User Roles. CoWeb Open Authoring Projects. Overall Conclusions. 12. Wiki at Work. In this Chapter. Case Studies. WikiWikiWeb. New York Times Digital. TWiki at TakeFive. TWiki at Motorola. Kehei Wiki Case Studies. A Rotary Wiki. Wiki Workplace Essentials. Why a Workplace Wiki? Planning the Wiki. Selection Stage. Implementation Stage. Day-to-Day Operations. Appendix A: Syntax Comparisons. Hyperlink Anchors. Markup Conventions. Escaped Blocks. HTML Tag Inclusion. Other Syntax Extensions Seen. Appendix B: Wiki Resources. Book Resources. Internet Resources. Appendix C: List of Tips. Index. 020171499XTO5232001
---
paper_title: Information revelation and privacy in online social networks

paper_content:

Participation in social networking sites has dramatically increased in recent years. Services such as Friendster, Tribe, or the Facebook allow millions of individuals to create online profiles and share personal information with vast networks of friends - and, often, unknown numbers of strangers. In this paper we study patterns of information revelation in online social networks and their privacy implications. We analyze the online behavior of more than 4,000 Carnegie Mellon University students who have joined a popular social networking site catered to colleges. We evaluate the amount of information they disclose and study their usage of the site's privacy settings. We highlight potential attacks on various aspects of their privacy, and we show that only a minimal percentage of users changes the highly permeable privacy preferences.
---
paper_title: Designing Virtual Organizations

paper_content:

Virtual Organizations are a suitable mechanism for enabling coordination of heterogeneous agents in open environments. Taking into account many concepts of the Human Organization Theory, a model for Virtual Organizations has been developed. This model describes the structural, functional, normative and environmental aspects of the system. It is based on four main concepts: organizational unit, service, norm and environment. All these concepts have been applied in a case-study example for the management of a travel agency system.
---
paper_title: Privacy-Preserving Query Answering in Logic-based Information Systems

paper_content:

We study privacy guarantees for the owner of an information system who wants to share some of the information in the system with clients while keeping some other information secret. The privacy guarantees ensure that publishing the new information will not compromise the secret one. We present a framework for describing privacy guarantees that generalises existing probabilistic frameworks in relational databases. We also formulate different flavors of privacy-preserving query answering as novel, purely logic-based reasoning problems and establish general connections between these reasoning problems and the probabilistic privacy guarantees.
---
paper_title: To join or not to join: the illusion of privacy in social networks with mixed public and private user profiles

paper_content:

In order to address privacy concerns, many social media websites allow users to hide their personal profiles from the public. In this work, we show how an adversary can exploit an online social network with a mixture of public and private user profiles to predict the private attributes of users. We map this problem to a relational classification problem and we propose practical models that use friendship and group membership information (which is often not hidden) to infer sensitive attributes. The key novel idea is that in addition to friendship links, groups can be carriers of significant information. We show that on several well-known social media sites, we can easily and accurately recover the information of private-profile users. To the best of our knowledge, this is the first work that uses link-based and group-based classification to study privacy implications in social networks with mixed public and private user profiles.
---
paper_title: Privacy-Preserving Data Publishing

paper_content:

Privacy is an important issue when one wants to make use of data that involves individuals' sensitive information. Research on protecting the privacy of individuals and the confidentiality of data has received contributions from many fields, including computer science, statistics, economics, and social science. In this paper, we survey research work in privacy-preserving data publishing. This is an area that attempts to answer the problem of how an organization, such as a hospital, government agency, or insurance company, can release data to the public without violating the confidentiality of personal information. We focus on privacy criteria that provide formal safety guarantees, present algorithms that sanitize data to make it safe for release while preserving useful information, and discuss ways of analyzing the sanitized data. Many challenges still remain. This survey provides a summary of the current state-of-the-art, based on which we expect to see advances in years to come.
---
paper_title: Deriving Private Information from Association Rule Mining Results

paper_content:

Data publishing can provide enormous benefits to the society. However, due to privacy concerns, data cannot be published in their original forms. Two types of data publishing can address the privacy issue: one is to publish the sanitized version of the original data, and the other is to publish the aggregate information from the original data, such as data mining results. There have been extensive studies to understand the privacy consequence in the first approach, but there is not much investigation on the privacy consequence of publishing data mining results, although, it is well believed that publishing data mining results can lead to the disclosure of private information. We propose a systematic method to study the privacy consequence of data mining results. Based on a well-established theory, the principle of maximum entropy, we have developed a method to precisely quantify the privacy risk when data mining results are published. We take the association rule mining as an example in this paper, and demonstrate how we quantify the privacy risk based on the published association rules. We have conducted experiments to evaluate the effectiveness and performance of our method. We have drawn several interesting observations from our experiments.
---

Title: A Survey of Privacy in Multi-Agent Systems

Section 1: Introduction
Description 1: Introduce the topic of privacy in multi-agent systems and the importance of safeguarding personal information within these systems.

Section 2: Protection against Information Collection
Description 2: Discuss mechanisms and strategies for preventing the unwanted collection of sensitive information by agents in multi-agent systems.

Section 3: Disclosure Decision Making
Description 3: Detail various approaches for agents to decide which information to disclose to other agents, including policy-based and privacy-utility tradeoff methods.

Section 4: Secure Data Transfer and Storage
Description 4: Explain the importance of securing information transfer and storage to protect privacy and review existing mechanisms in agent platforms.

Section 5: Trusted Third Party Computation
Description 5: Explore how trusted third parties can mediate information sharing to prevent direct information collection by destination agents.

Section 6: Protection against Information Processing
Description 6: Survey strategies to minimize and secure the processing of collected information to protect privacy.

Section 7: Anonymity
Description 7: Define anonymity in the context of multi-agent systems and discuss protocols and technologies that support anonymous communication and problem-solving.

Section 8: Anonymity in Multi-agent Problem Solving
Description 8: Review algorithms and approaches that ensure anonymity during distributed problem-solving among agents.

Section 9: Anonymizers
Description 9: Explore technologies like MIX networks and onion routing that anonymize agent communications and prevent traffic analysis.

Section 10: Pseudonymity
Description 10: Examine the use of pseudonyms to preserve privacy and discuss ad-hoc mechanisms and platform support for pseudonym management.

Section 11: Implications in Security
Description 11: Discuss how security measures such as authentication and accountability can impact privacy and describe solutions to balance these aspects.

Section 12: Implications in Trust and Reputation
Description 12: Investigate the role of trust and reputation models in multi-agent systems and how they can support privacy preservation.

Section 13: Summary of Proposals against Information Collection
Description 13: Summarize the approaches and mechanisms aiming to prevent undesired information collection in multi-agent systems.

Section 14: Summary of Proposals against Information Processing
Description 14: Summarize the approaches and mechanisms aiming to minimize and protect the processing of sensitive information.

Section 15: Protection against Information Dissemination
Description 15: Outline strategies based on trust, reputation, and norms to prevent unauthorized dissemination of collected information.

Section 16: Open Challenges
Description 16: Identify future research directions and open challenges in the field of privacy preservation in multi-agent systems.

Section 17: Conclusions
Description 17: Conclude the survey by summarizing the key points and emphasizing the importance of incorporating privacy preservation mechanisms in multi-agent systems.