公文是政府施政及機關間溝通的重要工具，所以公文處理效率為
政府效能之根基，也因為如此公文電子化成為e 化政府的改革要務之
一。綜觀公文處理過程陳核部份最為耗時，如果能導入公文線上簽核
系統，即可以加速公文辦理時效，同時也能順應節能減碳之時代潮
流。
本論文計畫針對安全的公文線上簽核系統，定義系統參與角色及
功能，並歸納其所需之安全需求，再整合代理簽章法、代理解密系統
及鑑別加密法等密碼機制，進一步提出「安全的公文線上簽核系統」
模型，包括：一般公文簽核法、公文代理簽核法及公文代理驗核法，
以營造線上簽核之安全環境，達成公文線上簽核之目的。
本論文所提出之「安全的公文線上簽核系統」，具高度模組化，
故可以適用於任何規模的組織機關，機關可以依據其組織內部的需求，
考量代理加密及代理驗核等需求，選擇適合組織公文線上簽核環境之
方法，以滿足機關個別公文線上簽核系統的運作需求，並維持其安全
性，包括公文機密性、公文完整性、公文鑑別性、簽核之不可否認性、
機密公文之可解密性、代理簽核之鑑別性、代理簽核之不可否認性、
代理簽核之可區別性、代理驗核、代理驗核之鑑別性及代理驗核之不
可否認性等安全需求。

Official document is an important media employed by government administration to correspond across public sectors. Therefore, the effectiveness of an official document can be regarded as the foundation of good government performance. Hence developing an efficient online
official document approval system is an important task required to bring about e-government plan to reality. Within the routine course of the official document scheme, approval is the most time consuming part of the process. If an online official document approval system can be implemented, aside from the benefits brought forward by shortening the time consumed, another advantage would be acting in accordance with the most recent worldwide call for action to lower energy consumption as well as reduce carbon dioxide emission.

This thesis focuses on the security issues of online official Document approval system. First, the roles and functions of the system would be defined. Second, the security needs of the system would be induced. Third,
by integrating the different aspects of cryptography scheme, such as proxy signature, proxy cryptosystem and authenticated encryption scheme;this thesis would design three modules that would address to security needs and further create a secured environment for online official
document approval system.

The system modules that this thesis has constructed can deal with most of the security requirements of online official document operating environment and can also satisfy other safety needs such as confidentiality of official document, integrity of official document,
authentication of official document, non-repudiation of approval,decryption of confidential official document, authentication of proxy approval, non-repudiation of proxy approval, distinguishability of proxy approval, proxy verification, authentication of proxy verification as well
as non-repudiation of proxy verification.

誌　謝 I
中文摘要 II
Abstract IV
參數符號表 VI
目　錄 VIII
圖標題 X
表標題 XI
第一章 緒論 1
1.1研究背景與動機 1
1.2研究目的與貢獻 4
1.3論文架構 10
第二章 文獻探討 13
2.1公文流程 13
2.2電子公文系統簡介 15
2.3線上簽核系統 18
2.4實務上公文線上簽核系統之架構 24
2.5電子表單系統 27
2.6 ElGamal密碼系統 29
2.7 Schnorr簽章法 31
2.8代理簽章 33
2.9代理解密 37
2.10鑑別加密法 38
2.11實務上處理公文線上簽核系統之簽章模式 43
2.12加密模式探討 48
第三章 一般公文簽核法 50
3.1一般公文簽核法之模型 51
3.2一般公文簽核法之設計 62
3.3一般公文簽核法 72
3.4一般公文簽核法之實例 74
3.5安全性分析 77
3.6效能分析 85
3.7討論 87
第四章 公文代理簽核法 88
4.1公文代理簽核法之模型 89
4.2公文代理簽核法之設計 98
4.3公文代理簽核法 105
4.4公文代理簽核法之實例 107
4.5安全性分析 111
4.6效能分析 116
4.7討論 117
第五章 公文代理驗核法 119
5.1公文代理驗核法之模型 119
5.2公文代理驗核法之設計 130
5.3公文代理驗核法 136
5.4公文代理驗核法之實例 139
5.5安全性分析 143
5.6效能分析 146
5.7討論 148
第六章 結論及未來研究方向 149
6.1結論 149
6.2未來研究方向 152
參考文獻 155
附錄 英中名詞對照表 162
作者簡介 167

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