Research areas of this dissertation are security for mobile agents, for applications based on mobile agents, and for distributed network environments in which mobile agents execute. Mobile agents paradigm has captured researchers’ and industry’s interests long time ago because of its innovative capabilities and attractive applications. The ability of mobile agents to autonomously migrate from host to host, transferring their code and internal state, enables them to accomplish tasks in network and distributed environments more conveniently, robustly, and efficiently than traditional client-server applications. But, in spite of significant benefits of the mobile agent paradigm, the technology is still mainly in a research domain and so far it has not been adopted on a large scale by the industry and users. One of the reasons for that is security related issues and security concerns. Current research in the area of mobile agents’ security is focused mainly on protection and security of agents and agents’ runtime platforms. But most of the currently available mobile agent systems do not support comprehensive security requirements for a general mobile agents paradigm. Therefore, there is a need for a complete and comprehensive security infrastructure for mobile agents, not only in the form of security services and mechanisms for agents’ runtime execution, but also as a complete set of infrastructural components, along with methodology for creation, classification, adoption, and validation of mobile agents before their deployment in real-environments. In addition, protection of mobile agents code and their baggage during execution is also needed. The lack of such concept, infrastructure and security solutions is hindrance for wider adoption of mobile agent systems at the time of this research. In our research, we solve these comprehensive requirements with solutions that can be classified in two groups: The first group is solutions for designing, implementation and deployment of a security infrastructure for mobile agents, along with methodology for secure deployment and execution of mobile agents. The proposed infrastructure for mobile agents is based on a methodology for creation, classification and validation of trusted mobile agents. It includes security architecture for publishing, discovery and adoption of mobile agents. Moreover, it provides integrated system for mobile agent deployment that supports launching, authorization and execution of mobile agents. Mobile agents execution is based on a protective approach, as compared to traditional detective or preventive methods, that not only provides code protection, but code execution and data privacy as well. The second group is solutions for use of security infrastructure and, in particular, secure and trusted mobile agents for real-life applications. The main result in this group is the design and implementation of a network intrusion detection and prevention system based on mobile agents. The system efficiently solves several problems of existing IDS/IPS. It can detect new vulnerabilities before they are exploited by hackers, it can process and filter large volumes of log entries, it reacts to intrusions in real–time, it provides protection against unknown attacks, it supports and improves commercial IDS/IPS products, and it also efficiently handles software patches. The system not only improves use of existing popular IDS/IPS, but it also eliminates several of their core problems. In addition, it is self–protected by full encryption, both of mobile agents and their execution platforms, and therefore not vulnerable to attacks against its own components and resources. / QC20100525

Mobile agents hold significant benefits for the rapid expansion of Internet applications and current trends in computing. Despite continued interest, the promised deployment has not taken place, indicating a need for a programming model to introduce novice mobile agent programmers to this environment/paradigm. Accordingly the research question asked was, ”Since novice mobile agent programmers1 require a paradigm shift to construct successful systems, how can they be equipped to grasp the contextual issues and gain the necessary skills within reasonable time limits?” To answer the question, a complete reference providing contextual information and knowledge of mobile agent system development was compiled. Simultaneously novices are introduced to agent orientation. A generic mobile agent system architectural model, incorporating guidelines for programming mobile agents, further provides a framework that can be used to design a mobile agent system. These two structures are presented in a knowledge base that serves as a referencing tool to unlock concepts and knowledge units to novices while developing mobile agent systems. / Computing / (M.Sc. (Computer Science))

Mobile agents hold significant benefits for the rapid expansion of Internet applications and current trends in computing. Despite continued interest, the promised deployment has not taken place, indicating a need for a programming model to introduce novice mobile agent programmers to this environment/paradigm. Accordingly the research question asked was, ”Since novice mobile agent programmers1 require a paradigm shift to construct successful systems, how can they be equipped to grasp the contextual issues and gain the necessary skills within reasonable time limits?” To answer the question, a complete reference providing contextual information and knowledge of mobile agent system development was compiled. Simultaneously novices are introduced to agent orientation. A generic mobile agent system architectural model, incorporating guidelines for programming mobile agents, further provides a framework that can be used to design a mobile agent system. These two structures are presented in a knowledge base that serves as a referencing tool to unlock concepts and knowledge units to novices while developing mobile agent systems. / Computing / (M.Sc. (Computer Science))

This study deals with the Distributed Buying Problem, that is, the problem faced by geographically distributed businesses when it comes to optimising buyer time and global businesses resources. It adopts a software agent-based approach to the problem. A literature survey was carried out to review the relatively new field of software agents and mobile agents in particular. The role of agents in electronic commerce was also studied. A mobile agent system was then designed and implemented to serve as a proof-ofconcept system for an agent-based solution to the problem. The design and implementation are then discussed. / Thesis (M.Sc.)-University of Natal, Durban, 2002.

Grades oportunistas são ambientes distribuídos que permitem o aproveitamento do poder de processamento ocioso de recursos computacionais dispersos geograficamente em diferentes domínios administrativos. São características desses ambientes a alta heterogeneidade e a variação na disponibilidade dos seus recursos. Nesse contexto, o paradigma de agentes móveis surge como uma alternativa promissora para superar os desafios impostos na construção de grades oportunistas. Esses agentes podem ser utilizados na construção de mecanismos que permitam a progressão de execução das aplicações mesmo na presença de falhas. Esses mecanismos podem ser utilizados isoladamente, ou em conjunto, de forma a se adequar a diferentes cenários de disponibilidade de recursos. Neste trabalho, descrevemos a arquitetura do middleware MAG (Mobile Agents for Grid Computing Environment) e o que ele pode fazer em ambientes de grades oportunistas. Utilizamos esse middleware como base para a implementação de um mecanismo de tolerância a falhas baseado em replicação e salvaguarda periódica de tarefas. Por fim, analisamos os resultados obtidos através de experimentos e simulações. / Opportunistic grids are distributed environments built to leverage the computacional power of idle resources geographically spread across different administrative domains. These environments comprise many charateristics such as high level heterogeneity and variation on resource availability. The mobile agent paradigm arises as a promising alternative to overcome the construction challenges of opportunistic grids. These agents can be used to implement mechanisms that enable the progress on the execution of applications even in the presence of failures. These mechanisms can be combined in a flexible manner to meet different scenarios of resource availability. In this work, we describe the architecture of the MAG middleware (Mobile Agents for Grid Computing Environment) and what it can do in an opportunistic grid environment. We use this middleware as a foundation for the development of a fault tolerance mechanism based on task replication and checkpointing. Finally, we analize experimental and simulation results.

O objetivo principal do presente trabalho é apresentar uma proposta que permita a combinação entre uma solução de captura de pacotes já existente e não muito flexível (sniffer) e o conceito de agentes móveis para aplicação em redes segmentadas. Essa pesquisa possui como foco principal a aplicação da técnica captura de pacotes em SDIs network based, utilizando para isso o modelo desenvolvido no ICMC (Cansian, 1997) e posteriormente adequado ao ambiente de agentes móveis (Bernardes, 1999). Assim sendo, foi especificada a camada base do ambiente desenvolvido em (Bernardes, 1999) visando as interações entre seus agentes e o agente de captura de pacotes. / The main objective of the current work is to present a proposal that allows the combination between an existent and not so flexible packet capture solution (sniffer) and the concept of mobile agents for application in switched networks. This research focuses the application of the packet capture technique in IDSs network-based, using for this purpose the model developed at ICMC (Cansian, 1997) and later adjusted to the mobile agents environment (Bernardes, 1999). Therefore, the base layer of the developed environment (Bernardes, 1999} was specified focusing the interactions between its agents and the packet capture agent.

by Mo Chun Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 72-80). / Abstracts in English and Chinese. / Chapter 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- The Mobile Agents --- p.2 / Chapter 1.2 --- The Mobile Agent Paradigm --- p.4 / Chapter 1.2.1 --- Initiatives --- p.5 / Chapter 1.2.2 --- Applications --- p.7 / Chapter 1.3 --- The Mobile Agent S ystem --- p.8 / Chapter 1.4 --- Security in Mobile Agent System --- p.9 / Chapter 1.5 --- Thesis Organization --- p.11 / Chapter 2 --- BACKGROUND AND FOUNDATIONS --- p.12 / Chapter 2.1 --- Encryption/Decryption --- p.12 / Chapter 2.2 --- One-way Hash Function --- p.13 / Chapter 2.3 --- Message Authentication Code (MAC) --- p.13 / Chapter 2.4 --- Homomorphic Encryption Scheme --- p.14 / Chapter 2.5 --- One-Round Oblivious Transfer --- p.14 / Chapter 2.6 --- Polynomial-time Algorithms --- p.14 / Chapter 2.7 --- Circuit --- p.15 / Chapter 3 --- SURVEY OF PROTECTION SCHEMES ON MOBILE AGENTS --- p.16 / Chapter 3.1 --- Introduction --- p.16 / Chapter 3.2 --- Detection Approaches --- p.17 / Chapter 3.2.1 --- Execution Traces --- p.17 / Chapter 3.2.2 --- Partial Result Encapsulation --- p.18 / Chapter 3.2.3 --- State Appraisal --- p.20 / Chapter 3.3 --- Prevention Approaches --- p.20 / Chapter 3.3.1 --- Sliding Encryption --- p.20 / Chapter 3.3.2 --- Tamper-resistant Hardware --- p.21 / Chapter 3.3.3 --- Multi-agent Cooperation --- p.22 / Chapter 3.3.4 --- Code Obfuscation --- p.23 / Chapter 3.3.5 --- Intention Spreading and Shrinking --- p.26 / Chapter 3.3.6 --- Encrypted Function Evaluation --- p.26 / Chapter 3.3.7 --- Black Box Test Prevention --- p.27 / Chapter 3.4 --- Chapter Summary --- p.29 / Chapter 4 --- TAXONOMY OF ATTACKS --- p.30 / Chapter 4.1 --- Introduction --- p.30 / Chapter 4.2 --- Whatis attack? --- p.31 / Chapter 4.3 --- How can attacks be done? --- p.32 / Chapter 4.4 --- Taxonomy of Attacks --- p.33 / Chapter 4.4.1 --- Purposeful Attack --- p.33 / Chapter 4.4.2 --- Frivolous Attack --- p.36 / Chapter 4.4.3 --- The Full Taxonomy --- p.38 / Chapter 4.5 --- Using the Taxonomy --- p.38 / Chapter 4.5.1 --- Match to Existing Protection Schemes --- p.38 / Chapter 4.5.2 --- Insight to Potential Protection Schemes --- p.41 / Chapter 4.6 --- Chapter Summary --- p.42 / Chapter 5 --- PROTECTION FOR REACTIVE MOBILE AGENTS --- p.43 / Chapter 5.1 --- Introduction --- p.43 / Chapter 5.2 --- The Model --- p.45 / Chapter 5.2.1 --- The Non-reactive and Reactive Mobile Agent Model --- p.45 / Chapter 5.2.2 --- The Computation Flow --- p.47 / Chapter 5.2.3 --- An Example --- p.49 / Chapter 5.3 --- tools --- p.51 / Chapter 5.3.1 --- Encrypted Circuit Construction --- p.51 / Chapter 5.3.2 --- Circuit Cascading --- p.53 / Chapter 5.4 --- Proposed Protection Scheme --- p.54 / Chapter 5.4.1 --- Two-hop Protocol --- p.55 / Chapter 5.4.2 --- Multi-hop Protocol --- p.60 / Chapter 5.5 --- Security Analysis --- p.60 / Chapter 5.5.1 --- Security under Purposeful Attacks --- p.61 / Chapter 5.5.2 --- Security under Frivolous Attacks --- p.62 / Chapter 5.6 --- Improvements --- p.62 / Chapter 5.6.1 --- Basic Idea --- p.63 / Chapter 5.6.2 --- Input Retrieval Protocol --- p.63 / Chapter 5.6.3 --- Combating Frivolous Attacks --- p.65 / Chapter 5.7 --- Further Considerations --- p.66 / Chapter 5.8 --- Chapter Summary --- p.67 / Chapter 6 --- CONCLUSIONS --- p.68 / APPENDIX --- p.71 / BIBLIOGRAPHY --- p.72

by Lam Tak-Cheung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 61-66). / Abstracts in English and Chinese. / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Evolution of the Mobile Agent Paradigm --- p.2 / Chapter 1.2 --- Beneficial Aspects of Mobile Agents --- p.3 / Chapter 1.3 --- Security Threats of Mobile Agents --- p.4 / Chapter 1.4 --- Organization of the Thesis --- p.6 / Chapter 2. --- Background of Cryptographic Theories --- p.7 / Chapter 2.1 --- Introduction --- p.7 / Chapter 2.2 --- Encryption and Decryption --- p.7 / Chapter 2.3 --- Six Cryptographic Primitives --- p.8 / Chapter 2.3.1 --- Symmetric Encryption --- p.8 / Chapter 2.3.2 --- Asymmetric Encryption --- p.9 / Chapter 2.3.3 --- Digital Signature --- p.9 / Chapter 2.3.4 --- Message Digest --- p.10 / Chapter 2.3.5 --- Digital Certificate --- p.11 / Chapter 2.3.6 --- Zero-Knowledge Proof --- p.11 / Chapter 2.4 --- RSA Public Key Cryptosystem --- p.12 / Chapter 2.5 --- Blind Signature --- p.13 / Chapter 2.6 --- Secret Sharing --- p.14 / Chapter 2.7 --- Conclusion Remarks --- p.14 / Chapter 3. --- Background of Mobile Agent Clones --- p.15 / Chapter 3.1 --- Introduction --- p.15 / Chapter 3.2 --- Types of Agent Clones --- p.15 / Chapter 3.3 --- Mobile Agent Cloning Problems --- p.16 / Chapter 3.4 --- Baek's Detection Scheme for Mobile Agent Clones --- p.17 / Chapter 3.4.1 --- The Main Idea --- p.17 / Chapter 3.4.2 --- Shortcomings of Baek's Scheme --- p.18 / Chapter 3.5 --- Conclusion Remarks --- p.19 / Chapter 4. --- Background of E-cash --- p.20 / Chapter 4.1 --- Introduction --- p.20 / Chapter 4.2 --- The General E-cash Model --- p.21 / Chapter 4.3 --- Chaum-Pedersen's General Transferable E-cash --- p.22 / Chapter 4.4 --- Ferguson's Single-term Off-line E-coins --- p.23 / Chapter 4.4.1 --- Technical Background of the Secure Tools --- p.24 / Chapter 4.4.2 --- Protocol Details --- p.27 / Chapter 4.5 --- Conclusion Remarks --- p.30 / Chapter 5. --- A Mobile Agent Clone Detection System using General Transferable E-cash --- p.31 / Chapter 5.1 --- Introduction --- p.31 / Chapter 5.2 --- Terminologies --- p.33 / Chapter 5.3 --- Mobile Agent Clone Detection System with Transferable E-cash --- p.34 / Chapter 5.4 --- Security and Privacy Analysis --- p.37 / Chapter 5.5 --- Attack Scenarios --- p.39 / Chapter 5.5.1 --- The Chosen Host Response Attack --- p.39 / Chapter 5.5.2 --- The Truncation and Substitution Attack --- p.40 / Chapter 5.6 --- An Alternative Scheme without Itinerary Privacy --- p.41 / Chapter 5.7 --- Conclusion Remarks --- p.43 / Chapter 6. --- Specific Implementation of the Mobile Agent Clone Detection System with Transferable Ferguson's E-coin --- p.45 / Chapter 6.1 --- Introduction --- p.45 / Chapter 6.2 --- The Clone Detection Environment --- p.46 / Chapter 6.3 --- Protocols --- p.48 / Chapter 6.3.2 --- Withdrawing E-tokens --- p.48 / Chapter 6.3.2 --- The Agent Creation Protocol --- p.51 / Chapter 6.3.3 --- The Agent Migration Protocol --- p.51 / Chapter 6.3.4 --- Clone Detection and Culprit Identification --- p.52 / Chapter 6.4 --- Security and Privacy Analysis --- p.54 / Chapter 6.5 --- Complexity Analysis --- p.55 / Chapter 6.5.1 --- Compact Passport --- p.55 / Chapter 6.5.2 --- Passport growth in size --- p.56 / Chapter 6.6 --- Conclusion Remarks --- p.56 / Chapter 7. --- Conclusions --- p.58 / Appendix 一 Papers derived from this thesis Bibliography

Chan, Hing-wing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 76-79). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract (Chinese) --- p.ii / Acknowledgements --- p.iii / Contents --- p.iv / List of Figures --- p.vii / List of Tables --- p.viii / Chapter Chapter 1. --- Introduction --- p.1 / Chapter 1.1. --- Mobile Agents and the Problems --- p.1 / Chapter 1.2. --- Approach --- p.3 / Chapter 1.3. --- Contributions --- p.3 / Chapter 1.4. --- Organization of This Thesis --- p.4 / Chapter Chapter 2. --- The Mobile Code Paradigm --- p.6 / Chapter 2.1. --- Mobile Code: an Alternative to Client/Servers --- p.6 / Chapter 2.1.1. --- Classification of Mobile Codes --- p.8 / Chapter 2.1.2. --- Applications of Mobile Code Paradigms --- p.10 / Chapter 2.1.3. --- Supporting Implementation Technologies --- p.11 / Chapter 2.2. --- The Problems of Mobile Code --- p.13 / Chapter 2.2.1. --- Security Issues in Distributed Systems --- p.13 / Chapter 2.2.2. --- Security Concerns of Mobile Code Paradigms --- p.15 / Chapter 2.2.2.1. --- Security Attacks --- p.15 / Chapter 2.2.2.2. --- Security Mechanisms --- p.17 / Chapter 2.2.2.3. --- A Security Comparison between Paradigms --- p.20 / Chapter 2.2.3. --- Security Features of Implementation Technologies --- p.20 / Chapter 2.2.3.1. --- Security Services of Message-based Technology --- p.21 / Chapter 2.2.3.2. --- Security Services of Object-based Technology --- p.21 / Chapter 2.2.3.3. --- Security Services of Mobile Technology --- p.22 / Chapter 2.2.3.4. --- A Comparison of Technologies on Security Services --- p.22 / Chapter 2.3. --- Chapter Summary --- p.23 / Chapter Chapter 3. --- "Mobile Agents, Its Security and Reliability Issues" --- p.24 / Chapter 3.1. --- Advantages and Applications of Mobile Agents --- p.24 / Chapter 3.2. --- Security Concerns of Mobile Agents --- p.26 / Chapter 3.2.1. --- Host Security --- p.27 / Chapter 3.2.2. --- Agent Security --- p.27 / Chapter 3.3. --- Techniques to Protect Mobile Agents --- p.29 / Chapter 3.3.1. --- Protected Agent States --- p.29 / Chapter 3.3.2. --- Mobile Cryptography --- p.30 / Chapter 3.4. --- Reliability Concerns of Mobile Agents --- p.31 / Chapter Chapter 4. --- Security and Reliability Modeling for Mobile Agents --- p.32 / Chapter 4.1. --- Attack Model and Scenarios --- p.33 / Chapter 4.2. --- General Security Models --- p.34 / Chapter 4.2.1. --- Security and Reliability --- p.34 / Chapter 4.2.2. --- Deriving Security Models --- p.36 / Chapter 4.2.3. --- The Time-to-Effort Function --- p.38 / Chapter 4.3. --- A Security Model for Mobile Agents --- p.40 / Chapter 4.4. --- Discussion of the Proposed Model --- p.43 / Chapter 4.5. --- A Reliability Model for Mobile Agents --- p.43 / Chapter Chapter 5. --- The Concordia Mobile Agent Platform --- p.46 / Chapter 5.1. --- Overview --- p.46 / Chapter 5.2. --- Special Features --- p.47 / Chapter Chapter 6. --- SIAS: A Shopping Information Agent System --- p.49 / Chapter 6.1. --- What the System Does --- p.49 / Chapter 6.2. --- System Design --- p.50 / Chapter 6.2.1. --- Object Description --- p.50 / Chapter 6.2.2. --- Flow Description --- p.52 / Chapter 6.3. --- Implementation --- p.53 / Chapter 6.3.1. --- Choice of Programming Language --- p.53 / Chapter 6.3.2. --- Choice of Mobile Agent Platform --- p.53 / Chapter 6.3.3. --- Other Implementation Details --- p.54 / Chapter 6.4. --- Snapshots --- p.54 / Chapter 6.5. --- Security Design of SIAS --- p.57 / Chapter 6.5.1. --- Security Problems of SIAS --- p.58 / Chapter 6.5.2. --- Our Solutions to the Problems --- p.60 / Chapter 6.5.3. --- Evaluation of the Secure SIAS --- p.64 / Chapter 6.5.3.1. --- Security Analysis --- p.64 / Chapter 6.5.3.2. --- Performance Vs Query Size --- p.65 / Chapter 6.5.3.3. --- Performance Vs Number of Hosts --- p.67 / Chapter 6.6. --- Reliability Design of SIAS --- p.69 / Chapter 6.6.1. --- Reliability Problems of SIAS --- p.69 / Chapter 6.6.2. --- Our Solutions to the Problems --- p.70 / Chapter 6.6.3. --- Evaluation of the Reliable SIAS --- p.71 / Chapter Chapter 7. --- Conclusions and Future Work --- p.73 / Bibliography --- p.76

Em decorrência do aumento do número de ataques de origem interna, a utilização de mecanismos de proteção, como o firewall, deve ser ampliada. Visto que este tipo de ataque, ocasionado pelos usuários internos ao sistema, não permite a localização imediata, torna-se necessário o uso integrado de diversas tecnologias para aumentar a capacidade de defesa de um sistema. Desta forma, a introdução de agentes móveis em apoio a segurança computacional apresenta-se como uma solução natural, uma vez que permitirá a distribuição de tarefas de monitoramento do sistema e automatização do processo de tomada de decisão, no caso de ausência do administrador humano. Este trabalho apresenta uma avaliação do uso do mecanismo de agentes móveis para acrescentar características de mobilidade ao processo de monitoração de intrusão em sistemas computacionais. Uma abordagem modular é proposta, onde agentes pequenos e independentes monitoram o sistema. Esta abordagem apresenta significantes vantagens em termos de overhead, escalabilidade e flexibilidade. / The use of protection mechanisms must be improved due the increase of attacks from internal sources. As this kind of attack, made by internal users do not allow its immediate localization, it is necessary the integrated use of several technologies to enhance the defense capabilities of a system. Therefore, the introduction of mobile agents to provide security appears to be a natural solution. It will allow the distribution of the system monitoring tasks and automate the decision making process, in the absence of a human administrator. This project presents an evaluation of the use of mobile agents to add mobile capabilities to the process of intrusion detection in computer systems. A finer-grained approach is proposed, where small and independent agents monitor the system. This approach has significant advantages in terms of overhead, scalability and flexibility.