| Summary: | 碩士 === 淡江大學 === 資訊管理學系碩士班 === 94 === Mobile agent is an important branch of the software agent family. It can travel autonomously on the network, and complete the task assigned by the user. The mobile agent inherits the advantage of the software agents so it can handle regular and tedious work for the user. In particular, it can reduce the amount of data transmitted on the network, save transmitting time effectively, and therefore is very suitable for the environment which handheld devices (cell phone, PDA, etc.) are mainly applied. Although mobile agents have foregoing advantages, in the practical process, many key problems remain to be solved. First, mobile agents have to travel among the nodes of the network, opportunities of attacking their code and data are increasing, so the security problems are obviously more difficult than traditional client-server structure [6][15]. In addition, because of the network accessing expenses of the handheld devices remaining high, roaming without planning on the network will force the owner of the mobile agents to pay the expensive cost. Hence, how to schedule itinerary well according to the changing environment is also indispensable for developing industrial strength mobile agents [10].
In this research, cell phones are used as the target devices to develop effective mobile agents encryption and proper itinerary scheduling method. In encrypting, differing from the previous studies, we consider the restricted computational capability of mobile devices, digest the additional data which is only used to confirm the security first in order to speed up the process of encrypting and decrypting. Furthermore, in order to prevent the agent’s key being forged during the journey, the certification signed by CA (Certificate Authority) is attached to data carried by the agent to confirm the dependability of its source. To the itinerary scheduling problem, we propose a fast greedy algorithm, which groups automatically according to the communication cost among the cell phones first, then a selection procedure are applied repeatedly to schedule the itinerary among the groups. The experimental result shows that the proposed encrypting method can certainly consider both security and efficiency. In addition, the route produced by our scheduling method is nearly similar to the method proposed in [10], but the former can save a large amount of operation time.
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