最近橢圓曲線加密系統被廣泛地應用在各個領域，例如電子投票系統、電子現金系統、電子簽章架構、智慧卡系統以及金鑰協商機制和身份認證協定等等。橢圓曲線加密系統的與基於離散對數問題的加密系統相同具有相同的安全性，但是在執行上卻更具有效率。因此，橢圓曲線加密系統可以說是一個具有實用性的系統。我們在這篇論文中分析了幾個現有的電子投票系統與具可否認性身分認證協定，並且設計了一個新的電子投票系統和提出一個新的具可否認性身分認證協定。 Recently, the bilinear pairings cryptosystem over ellipse curve is widely used on varieties of schemes such as electronic voting system, electronic cash system, digital signature scheme, smart card system, key agreement protocol and authentication protocol etc. The security of bilinear pairings cryptosystem is equal to the cryptosystem based on discrete log problem, but it is more efficient than the latter. Hence, the bilinear pairings cryptosystem is a practical cryptosystem. In this paper, we analyze several current electronic voting protocols and deniable authentication protocols. Then we design an electronic voting protocol and propose a deniable authentication protocol both based on bilinear pairings. The new electronic voting protocol can satisfy the security requirements of an e-voting system and the proposed deniable authentication protocol can not only attain the desired deniable property but also can prevent all known attacks.
