階層式金鑰管理及其在行動運算環境上之應用

Hierarchical Key Management and its Application in Mobile Computing Environment

鐘玉芳(Yu-Fang Chung)

指導教授 ： 賴飛羆

國立臺灣大學/電機資訊學院/電機工程學研究所/博士(2007年)

https://doi.org/10.6342/NTU.2007.02846

摘要

電腦網路與電腦技術的發展，固然得以提供使用者一個開放、公開的操作環境，進行資源的分享。然而，如何確保合法的存取以及資料的機密性，無疑將是資源分享環境中的ㄧ大挑戰。有鑑於網路環境中無法預期的種種現象，例如：未經授權的存取要求、存取資料方的權限不符合、或是使用者資料遭侵入等情形。從這種種問題當中，適足以顯示出存取控制機制的重要性。
階層式金鑰管理中的存取控制問題，主要在於解決組織中的金鑰產生及存取問題，因此，使用者可以透過所取得的金鑰，進行有效的存取，同時也避免個人的資料遭到未經授權的存取。
因此，本文中提出三種不同的存取控制機制，都是應用在具有偏序關係的階層結構中，其中，每一個群組都可以棣屬於多個直屬群組。這三種方法分別使用不同的數學背景，包括單向雜湊函數、中國餘數定理、以及橢圓曲線密碼系統，用以確保秘密金鑰的安全性，並且達到動態管理問題的需求，諸如：群組的新增與刪除、群組關係的異動、以及更改秘密金鑰等問題的解決方案。
此外，在傳統集中式的網路管理方式中，主機端會因網路系統的規模擴大所帶來的工作量增加，必須與分散於各地的用戶端傳遞訊息及交換資料，造成網路流量增加，導致工作效能降低。同時，主機端與用戶端之間頻繁的資料交換，也會耗費大量的網路頻寬，造成效能不彰的現象，使得系統的管理在目前趨於龐大且分散的網路架構中，面臨相當大的難處，舉凡可靠度、互動性、擴充性、彈性不足等問題皆是。
因此，本文中提出一個階層式的行動運算機制，可適用於支援分散式環境中的存取控制問題，用以處理行動代理者彼此之間、或主機與行動代理者之間的金鑰管理及存取。在提升金鑰管理上的安全問題的同時，也達到在不特定網路上進行分散式環境的存取控制的功能需求。

關鍵字

階層式金鑰管理 ； 存取控制問題 ； 中國餘數定理 ； 橢圓曲線密碼系統 ； 行動代理 ； 分散式環境

並列摘要

Development of computer network and computer technology will no doubt provide users with an open and public runtime environment for resource sharing. However, ensuring legal access and confidentiality of data will undoubtedly be a big challenge in resource sharing environment. An examination of the different types of unpredictable phenomena in network environment, for instance, situations like unauthorized access request, user access rights not matching, or violation of user data, sufficiently shows the importance of access control.
Access control in hierarchy key management mainly lies in solving the key generation and access problem among groups. So, users can effectively access data through the acquired key, and at the same time avoid personal data from unauthorized access.
Therefore, this study presents three different types of access control schemes, all of which are used in hierarchies with order relation that is bias. Among which, each group can be subordinate to many immediate groups. Each of these three methods uses a different mathematic background, including one-way hash function, Chinese remainder theorem, and elliptic curve cryptosystem, to ensure the security of the secret key, and to meet the requirements of dynamic management such as solution to problems like adding and deleting groups, modifying relationships among groups, and changing of secret key, etc.
Besides, in conventional centralized network administration method, due to the increased workload brought on by enlarged network systems, a host must send messages and exchange data with clients that are distributed. This causes net-flow to increase leading to a drop in work efficiency. At the same time, the frequent exchange of data between host and clients also uses up large amount of network bandwidth, eating into efficiency. This causes the system administration, which presently tends toward large and distributed network framework, to face a considerably large problem relating to dependability, interactivity, expandability, and inelasticity.
For this reason, this study also proposes a hierarchical mobile operation scheme that can be used to solve access control problems in distributed environment, to handle access and key management between mobile agent and mobile agent or mobile agent and host server. At that same time that the proposed scheme alleviates security problems in key management, it also meets the functionality requirements of access control in distributed environment on undesignated network.

並列關鍵字

Hierarchical key management ； Access control problem ； Chinese remainder theorem ； Elliptic curve cryptosystem ； Mobile agent ； Distributed environment

參考文獻

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