Designing and Implementing a Secure, Portable, and Efficient Mobile Agent Kernel

Doctoral Thesis / Dissertation from the year 2001 in the subject Computer Science - Commercial Information Technology, Vienna University of Technology (Technische Naturwissenschaften und Informatik), language: English, abstract: Inhaltsangabe:Abstract:§Even though the benefits of mobile agents have been highlighted in numerous research works, mobile agent applications are not in widespread use today.§For the success of mobile agent applications, secure, portable, and efficient execution platforms for mobile agents are crucial. However, available mobile agent systems do not meet the high security requirements of commercial applications, are not portable, or cause high overhead.§Currently, the majority of mobile agent platforms is based on Java. These systems simply rely on the security facilities of Java, although the Java security model is not suited to protect agents and service components from each other.§Above all, Java is lacking a concept of strong protection domains that could be used to isolate agents.§The J-SEAL2 mobile agent system extends the Java environment with a model of strong protection domains.§The core of the system is a micro-kernel fulfilling the same functions as a traditional operating system kernel: Protection, communication, domain termination, and resource control. For portability reasons, J-SEAL2 is implemented in pure Java. J-SEAL2 provides an efficient communication model and offers good scalability and performance for large-scale applications. This thesis explains the key concepts of the J-SEAL2 micro-kernel and how they are implemented in Java.§Inhaltsverzeichnis:Table of Contents:§1Overview5§1.1Introduction5§1.2Mobile Agent Systems in Java8§1.3J-SEAL2 System Structure10§1.4J-SEAL2 Security Properties12§2.Related Work14§2.1Java Operating Systems14§2.1.1JavaSeal14§2.1.2KaffeOS16§2.1.3Alta16§2.1.4J-Kernel17§2.1.5Luna17§2.1.6NOMADS17§2.2Resource Control in Java18§2.2.1Jres18§2.2.2Real-time Extensions for Java18§2.2.3Java Profilers19§2.2.4Economic Models19§3.Protection Domains21§3.1Introduction21§3.2Kernel Code21§3.2.1Requirements22§3.2.2Implementation Issues23§3.3Protection24§3.3.1Requirements24§3.3.2Implementation Issues26§3.3.2.1Class-loading26§3.3.2.2Extended Bytecode Verification26§3.4Domain Termination28§3.4.1Requirements28§3.4.2Implementation Issues29§4.Communication31§4.1Introduction31§4.2Channels32§4.3Limitations of Channels32§4.4External References33§4.4.1Terminology34§4.4.2Properties of External References35§4.4.3Examples of External References39§4.5Implementation Issues40§4.6Inter Agent Method Calling (IAMC)41§4.7Evaluation43§5.Resource Control45§5.1Introduction45§5.2Objectives and Resulting Model46§5.2.1Portability and Transparency48§5.2.2Minimal Overhead for Trusted Domains49§5.2.3Support for Resource Sharing49§5.2.4Managed Resources49§5.3API51§5.3.1Definitions51§5.3.2Class Res52§5.3.3Class ResSet54§5.3.4Class Seal55§5.3.5Example56§5.4Implementation Issues56§5.4.1No Direct Sharing57§5.4.2Bytecode Rewriting57§5.4.3Domain Types58§5.4.4Accounting Objects58§5.4.5Callbacks from Native Code60§5.4.6Shared Classes61§5.4.7Optimizations62§5.4.8Rewriting Abstract Methods63§5.4.9Memory Control64§5.4.9.1Heap64§5.4.9.2Stack65§5.4.10CPU Control66§5.4.10.1Class CPUAccount66§5.4.10.2Scheduler67§5.4.10.3Rewriting Algorithm69§5.4.10.4Optimizations71§5.4.11Accounting for Garbage Collection73§5.4.12Compensating for Native Code74§5.5Evaluation75§6.Conclusion80§6.1State of Implementation...