植基於電子圖章的數位簽章技術

Electronic Stamp Technology Based on Digital Signature

林麗麗(Suryati)

指導教授 ： 姚修慎

元智大學/資訊學院/資訊工程學系/碩士(2003年)

摘要

現實生活中，為了要向他人證明自己對文件負責，或是證明該文件確實是由自己所發出的，通常會在文件上加蓋自己的印章以資證明。例如：在買賣契約書上加以蓋章，如此才可以確定交易雙方彼此相關的權利與義務。同樣地，在電子商務的環境中，交易雙方透過各式電子文件來完成商業交易行為，而這些電子文件則必須仰賴電子簽章來保證其真確性與不可否認性，以確立交易雙方的權利與義務。
本研究最主要的目的是提供一個具有可攜性（portability）、視覺性（visibility）、不可否認性（non-repudiation）以及鑑定性（authenticity）的電子圖章。我們將數位簽章內容儲存在USB（Universal Serial Bus） key，便可達到可攜性和方便性。使用者只需按下USB key的按鈕便可以在文件上蓋章，完全的將人類的習性模擬在電腦應用上。視覺性的目標是讓使用者可以用肉眼就可辨認該圖章是否屬於自己的。為了達到此目標，我們希望圖章是唯一的，既使多個使用者有相同的姓名或有其他相同的特徵，屬於他們的圖章都是唯一的，可以被辨認。此目標可以由圖章刻痕達到。針對不可否認性。因為每支USB key有唯一的辨識碼，只要是用該USB key蓋章，則不能否認該文件是由蓋章者所蓋的。至於鑑定性，利用RSA（Rivest — Shamir — Adleman）標準金鑰對，秘密金鑰和公開金鑰，以及我們所提出的演算法辨認圖章的真偽。另外，針對文件部分，我們也會做檢查，蓋章後的文章是否有被修改。

關鍵字

電子圖章 ； 數位簽章 ； 不可否認簽章

並列摘要

In the real world, we always sign or seal stamp on the document we revise to show that we are responsible for it or to prove that the document is indeed issued by us. For instance: in a commerce contract, both seller and buyer seal their stamps on the contract document to ensure the rights and responsibilities of the both. Similarly, any electronic documents involved in e-commerce transactions also need to be authorized validated. In this case, the digital signature technique is always used. Digital signature technologies developed at present have the same drawback — they do not have a signature appearance. The main concern of using such kinds of digital signature is that user has been used to see a seal on document to be convinced about its validity.
The main objective of this research is to provide an electronic stamp (shorten as e-stamp) that has the portability, visibility, non-repudiation and authenticity characteristics. To reach the portability and convenience characteristics, we store the content of e-stamp in a USB key device so that the stamp is practically portable. Users need only to press the button on the top of the USB key to seal a stamp. This implementation simulates the habitual behavior of human being to deal with documents into the computer and electronic environment. The visibility characteristic means to let user identify his/her own unique stamp with naked eyes, if there are nearly similar stamps exist. This objective can be achieved by recognizing the pattern carved on the stamp. Non-repudiation is achieved since each USB key has its own unique identifier number, while the authenticity is achieved by both the RSA (Rivest — Shamir — Adleman) algorithm and the approach we propose in this paper to identify the genuineness of stamp. We also perform the check whether there is any modification to the document after a stamp has been sealed on it.

並列關鍵字

Electronic Stamp ； Digital Signature ； Undeniable Signature ； USB key

參考文獻

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