臺灣博碩士論文加值系統

在現代數位化的時代中，數位簽章常被利用於各種電子文件的簽署。而在過去，數位簽章通常都是要由簽章人自行來產生，如此一來也造成了許多的不便。因此，為了破除這種當簽章者不在便不能簽署文件的窘境，有學者提出了代理簽章的概念。如此一來，就算簽署者不在，亦可以指定一位代理人來幫他執行簽章的動作以產行有效的數位簽章。然而在相較於結構較為鬆散及節點流動性極大的Ad-hoc網路環境下，目前並沒有一個較為適合的代理簽章方式可以套用。因此，本篇論文便試著將各種現存的代理簽章方式截長補短，以Threshold Proxy Signature中的secret sharing方法來分散運算，此外，亦搭配El-Gamal的觀念來提高新方法的security，提出一個更符合Ad-hoc網路環境的分散式提名代理簽章方法，而在論文的最後面，我們會利用Manik Lal Das提出的幾點數位代理簽章安全性需求及Kaliski提出的方法來對新舊方法做分析評估，以證明新方法較具安全性及彈性

Digital signature which is usually used in many kinds of digital documents and only generated by the original signer in this digital age may result in several inconveniences. So, in order to solve the dilemma that digital signatures can’t be generated without the original signer, some scholars proposed a new scheme called Proxy Signature. By the showing up of Proxy signature scheme, the original signer could designate a proxy to perform the signing by generating valid digital signatures on behalf of the original signer when it is not there. However, there is no suitable scheme which could be applied to the Ad-hoc network environment due to its loose structure and unstable topology of mobile nodes. In order to find out a new scheme that could be used in Ad-hoc network environment, I tried to collect and analysis advantages and disadvantages of every related scheme, for example, I try to incorporate the secret sharing mechanism of Threshold Proxy Signature into my new mechanism, besides, I also benefit from using the concept of El-Gamal to improve the security to make a more suited distributed nominative proxy signature mechanism for Ad-hoc network. At last, we will show better security and flexibility the new mechanism has by Manik Lal Das’s basic proxy signature scheme security requirements and Kaliskis’ methodology to perform computing time analysis.

第一章 緒論 1
1.1 研究背景與動機 1
1.2 研究目的 2
1.3 章節介紹 3
第二章 文獻探討 4
2.1 無線網路 4
2.1.1 何謂無線網路 4
2.1.2 Ad-hoc Networking 5
2.2 代理簽章機制 8
2.3 提名式代理簽章 11
2.4 Threshold Proxy Signature 13
2.4.1 Verifiable Secret Sharing Scheme 13
2.4.2 Conventional threshold signature 14
2.5 Zuo-Wen Tan與Zhuo-Jun Liu提名式代理簽章 15
2.6 Kaliski評估法 17
第三章 分散式提名代理簽章 20
3.1 問題分析 20
3.2 分散式提名代理簽章機制 20
3.2.1 演算法 21
第四章 分析與比較 27
4.1 安全性分析 27
4.2 Computation Time評估 29
4.3 比較結果 37
第五章 結論與未來研究方向 38
5.1 結論 38
5.2 未來發展 38
參考文獻 39

[1] Ting-Yi Chang, Chou-Chen Yang and Min-Shiang Hwang, “A threshold signature scheme for group communications without a shared distribution center”, 2003
[2] Rosario Gennaro, Stanistaw Jarecki,, Hugo Krawczyk and Tal Rabin, “Robust Threshold DSS Signatures”, March 3, 1997
[3] Manik Lal Das, Ashutosh Saxena and V P Gulati, “Security Analysis of Lal and Awasthi’s Proxy Signature Schemes”, Institute for Development and Research in Banking Technology
[4] Masahiro MAMBO, Keisuke USUDA and Eiji OKAMOTO, “Proxy signatures for Delegating Signing Operation”, School of Information Science, Japan Advanced Institute of Science and Technology, 1996 ACM
[5] H.-M.Sun, N.-Y.Lee and T.Hwang, “Threshold proxy signatures”, IEE Proc.-Computers & Digital Techniques, Vol. 146, No. 5, September 1999
[6] Zuo-Wen Tan and Zhuo-Jun Liu, “Nominative Proxy Signature Schemes”, Institute of Systems Science , AMSS, Chinese Academy of Sciences, State Key Laboratory of Information Security, Graduate School of Chinese Academy of Sciences, 2004
[7] Jianhong Zhang, Qianhong Wu, Jilin Wang and Yumin Wang, “An Improved Nominative Proxy Signature Scheme for Mobile Communication”, Key Laboratory of the Ministry Education, Xidian University, Proceedings of the 18th International Conference on Advanced information Networking and Application, 2004 IEEE
[8] Jianhong Zhang, Jiancheng Zou, Member, IEEE and Yumin Wang, Member, IEEE, “Two Modified Nominative Proxy Signature Schemes for Mobile Communication”, 2005 IEEE