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    1 : Mobile Agents By Olga Gelbart
    2 : What is an agent? A program (“software agent”), e.g., Personal assistant (mail filter, scheduling) Information agent (tactical picture agent) E-commerce agent (stock trader, bidder) Recommendation agent (Firefly, A program that can interact with users, applications, and agents collaborate with the user Software agents help with repetitive tasks
    3 : Is everything an “agent”? Not all programs are agents Agents are customized persistent autonomous adaptive
    4 : What is a mobile agent? Machine A Machine B Search engine Mobile agent: Agent that migrates from machine to machine in a heterogeneous network at times of its own choosing
    5 : Definition In a broad sense, an agent is any program that acts on behalf of a (human) user. A mobile agent then is a program which represents a user in a computer network, and is capable of migrating autonomously from node to node, to performs some computation on behalf of the user.
    6 : How it works?
    7 : Mobile Agent Attributes Code State Execution state Object state Name Identifier Authority Agent system type Location
    8 : Evolution of the “mobile agent” paradigm
    9 : Assumptions about computer systems violated by mobile agents Whenever a program attempts some action, we can easily identify a person to whom that action can be attributed, and it is safe to assume that that person intends the action to be taken. Only persons that are know to the system can execute programs on the system. There is one security domain corresponding to each user; all actions within that domain can be treated the same way. Single-user systems require no security. Essentially all programs are obtained from easily identifiable and generally trusted sources The users of a given piece of software are restrained by law and custom from various actions against the manufacturer’s interests
    10 : Assumptions violated by mobile agents (cont’d) Significant security threats come from attackers running programs with the intent of accomplishing unauthorized results. Programs cross administrative boundaries only rarely, and only when people intentionally transmit them. A given instance of a program runs entirely on one machine; processes do not cross administrative boundaries at all. A given program runs on only one particular operating system. Computer security is provided by the operating system
    11 : Benefits of mobile agents Bandwidth conservation Reduction of latency Reduction of completion time Asynchronous (disconnected) communications Load balancing Dynamic deployment
    12 : Reason 1: Bandwidth conservation Server Text documents, numerical data, etc. Client/Proxy Client/Proxy Server Dataset
    13 : Reason 2: Reduce latency Sumatra chat server (a “reflector”) 1. Observe high average latency to clients 2. Move to better location
    14 : Reason 3: Reduce Completion Time Efficiency Mobile users 1. Send code with unique query 2. Perform multi-step queries on large, remote, heterogeneous databases 3. Return requested data Low bandwidth channel
    15 : Reason 4: Disconnected communication and operation X X X X Before After
    16 : Reason 5: Load balancing Jobs/Load Jobs/Load migrate in a heterogeneous network of machines
    17 : Reason 6: Dynamic Deployment
    18 : Threats posed by mobile agents Destruction of data, hardware, current environment Denial of service block execution take up memory prevention of access to resources/network Breach of privacy / theft of resources obtain/transmit privileged information use of covert channels Harassment Display of annoying/offensive information screen flicker Repudiation ability to deny an event / action ever happened
    19 : Protection methods against malicious mobile agents Authenticating credentials certificates and digital signatures Access Control and Authorization Reference monitor security domains policies Software-based Fault Isolation Java’s “sandbox” Monitoring auditing of agent’s activities setting limits Proxy-based approach to host protection Code Verification - proof-carrying code
    20 : Threats to mobile agents Denial of service Unauthorized use or access of code/data Unauthorized modification or corruption code/data Unauthorized access, modification, corruption, or repeat of agent external communication
    21 : Possible attacks on mobile agents Denial of service Impersonation Host Agent Replay Eavesdropping Communication Code & data Tamper attack Communication Code & data
    22 : Protection of mobile agents Encryption code payload Code obfuscation Time-limited black-box security
    23 : Application: Technical reports Dynamically selected proxy site 1. Send agent 3. Return merged and filtered results GUI on home machine ... 2. Send child agents / collect partial results
    24 : Application: Military Wireless Network Technical specs Orders and memos Troop positions Wired network
    25 : Application: e-commerce Bank Arbiter VendorA Yellow pages VendorB Agent Agent
    26 : Mobile agent systems
    27 : More examples and “bots” Tryllian mobile agent system Bots - customer preferences
    28 : Current trends lead to mobile agents Information overload Diversified population Bandwidth gap Mobile users and devices “Customization” Proxy-based Server-side Avoid large transfers Disconnected Operation Mobile code to client Mobile code to server or proxy Mobile Agents High latency Increased need for personalization Too many unique, dispersed clients to handle Multiple sites to visit Avoid “star” itinerary
    29 : Migrating to migrating code
    30 : Conclusion: Cons Security is too big a concern Overhead for moving code is too high Not backward compatible with Fortran, C …. Networks will be so fast, performance not an issue
    31 : Conclusion: Pros A unifying framework for making many applications more efficient Treats data and code symmetrically Multiple-language support possible Supports disconnected networks in a way that other technologies cannot Cleaner programming model
    32 : For more information... D’Agents: Tryllian: Aglets:

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