臺灣博碩士論文加值系統

數位簽章 (digital signature）是電腦網路通訊雙方互信的基礎，也是電子商
務能否普及的最重要關鍵。數位簽章的應用環境和方式變化繁多。雖然近年來
國內外的專家和學者已經發展了許多不同類型的簽章技術以因應不同的應用環
境需求；然而隨著網路通訊活動的方式和結構愈來愈複雜，有愈來愈多的應用
系統會需要各種不同類型的簽章技術的支援，例如具有匿名性及不可追踨性的
盲簽章，及由可授權可信賴第三人，代為行使數位文件簽署的代理簽章。
代理盲簽章結合了盲簽章與代理簽章的雙重優點，因而可適用於某些電子
商務環境的應用之上，在2002年Tan等首先提出基於離散對數及楕圓曲線離散對
數困難度的代理盲簽章機制，然而這兩個代理盲簽章機制都被證明有被偽造簽
章及追踨使用者的缺點。之後雖然也有許多學者提出各種不同技術的代理盲簽
章機制，然而這些代理盲簽章系統都需要大量的系統運算及繁複的資訊交換流
程，如果在執行大量數位文件簽署的情形下恐怕會因過高的運算負擔使整個系
統的效能及安全性降低。
在本論文中我們改進Mehta與Harn的代理簽章而設計出新式高效率代理盲
簽章，新的代理盲簽章不但符合所有代理盲簽章的安全需求，還擁有系統運算
量低、執行流程精簡、有效限制代理權力以及在發生內部爭議時快速判斷是誰
違反協定等優點，相較於先前的代理盲簽章，我們的研究成果更能夠提昇代理
盲簽章系統安全性及運算效能，讓代理盲簽章技術更符合未來電子投票系統或
電子商務環境需求。

The proxy blind signature scheme becomes important because of its application
in e-commerce with the advantages of the proxy signature scheme and the blind
signature scheme. Many researchers proposed useful proxy blind signature schemes
in these years. Tan et al. proposed two proxy blind signature schemes based on
discrete logarithm problem and ecliptic curve discrete logarithm problem respectively.
Lal and Awasthi pointed out that Tan et al.’s schemes were subject to forgery attacks
on the signature receiver’s side. Then proposed their own secure proxy blind
signature scheme to mend the drawback in Tan et al.’s schemes they pointed out.
Recently, Wang et al. also proposed a secure efficient proxy blind signature scheme
based on discrete logarithm problem to overcome the pointed out drawbacks in Tan et
al.’s schemes. Compared with existing proxy blind signature schemes, Wang et al.’s
scheme is more efficient. After our analyses, we found that most of proxy blind
signature schemes are based on blind signature. In order to achieve unforgeability and
unlinkability properties, these proxy blind signature systems need to implement many
times of information interchange to complete a signature. Therefore, the efficiency of
these proxy blind signature schemes is limited. In this thesis, we propose a novel
proxy blind signature scheme based on Mehta and Harn’s one-time proxy signature
scheme. In the proposed scheme, the requesters only need to implement the
information interchange once. It is shown that the proposed scheme satisfies all
important security requirements, and is more efficient.

誌謝...........................................................................................................................ii
摘要..........................................................................................................................iii
ABSTRACT............................................................................................................. iv
目錄........................................................................................................................... v
表目錄.....................................................................................................................vii
圖目錄....................................................................................................................viii
第一章 緒論............................................................................................................. 1
1.1 研究背景與動機......................................................................................... 1
1.2 研究目的..................................................................................................... 5
1.3 論文架構..................................................................................................... 6
第二章 文獻研究與回顧......................................................................................... 7
2.1 盲簽章(Blind Signature)........................................................................... 10
2.1.1 D.Chaum 的盲簽章系統................................................................. 12
2.1.2 M. Stadler 等人的公平盲簽章........................................................ 14
2.1.3 P.L. Yu 與 C. L. Lei 的高效率公平盲簽章.................................. 15
2.1.4 Chen等的電子投票系統.................................................................. 18
2.1.4.1 系統架構與流程........................................................................... 20
2.1.4.2 安全性分析及改進建議............................................................... 25
2.2 代理簽章................................................................................................... 28
2.2.1 Mambo等的代理簽章...................................................................... 32
2.2.2 Sun與Hsieh的代理簽章................................................................... 33
2.2.3 Yen等的代理簽章............................................................................ 34
vi
2.3 代理盲簽章............................................................................................... 35
2.3.1 Tan等的代理盲簽章......................................................................... 36
2.3.2 Lal與Awasthi的代理盲簽章............................................................ 38
2.3.3 Wang等的代理盲簽章..................................................................... 40
第三章 Mehta與Harn的高效率代理簽章系統.................................................... 44
3.1 系統設定階段........................................................................................... 46
3.2 代理授權階段........................................................................................... 47
3.3 文件簽署階段........................................................................................... 48
3.4 簽章驗證階段........................................................................................... 49
第四章 新式代理盲簽章系統.............................................................................. 51
4.1 系統設定階段........................................................................................... 51
4.2 代理授權階段........................................................................................... 52
4.3 文件簽署階段............................................................................................ 53
4.4 簽章驗證階段........................................................................................... 55
4.5 安全性與效率分析................................................................................... 56
第五章 結論與未來研究方向.............................................................................. 60
5.1 結論........................................................................................................... 60
5.2 未來研究方面........................................................................................... 60
參考文獻................................................................................................................. 61
自傳......................................................................................................................... 64

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