具時間限制的三方加密金鑰交換協議之研究

The Study of Three-Party Encrypted Key Exchange Protocol with Time Constraint

莊賢耘(Hsien-Yun Chuang)

指導教授 ： 陳興忠

亞洲大學/資訊學院/資訊工程學系碩士班/碩士(2010年)

摘要

在2004年，張等學者提出一種新的3PEKE協議，它是不需要使用伺服器的公開金鑰。然而在2008年，尹和陳等學者證明張等學者的協議不能抵抗察覺不到的線上密碼猜測攻擊。然後，尹和陳等學者分別提出了一個新的方法來解決張等學者的安全問題。但是在2009年，羅等學者證明了無論尹等學者還是陳等學者都不能有效地防止察覺不到的線上密碼猜測攻擊，並且提出了改進的方法。實際上雖然他們提出了一種改進方法，這種方法在客戶充當交換訊息的角色上是不同於傳統的3PEKE協議。即傳統的3PEKE協議的其中一方客戶端仍然會在交換信息時扮演另一方客戶端與伺服器之間協助轉送信息的中介角色。換而言之，羅等學者所提出的方法中，這兩個客戶端都扮演著各別與伺服器進行交換訊息的角色。
因此，我們提出了三種方法，被保護的密碼驗證之3PEKE協議、利用時間戳記增強的3PEKE協議和具時間限制之增強的3PEKE協議，來改善傳統的3PEKE協議。我們的協議能夠實現並有效地實行和抵抗察覺不到的線上密碼猜測攻擊，並且加強3PEKE系統的安全性。

關鍵字

3PEKE ； 金鑰交換協議 ； 認證 ； 安全 ； 時間戳記 ； 密碼 ； 時間限制

並列摘要

In 2004, Chang et al. proposed a new 3PEKE (three-party encrypted key exchange) scheme which is without using the server's public keys. However, in 2008, both Yoon et al. and Chen et al. showed that Chang et al.’s scheme cannot resist undetectable on-line password guessing attacks. And then, Yoon et al. and Chen et al. respectively proposed a new approach to solve Chang et al.'s problem of security. But in 2009, Lo et al. proved that both Yoon et al. and Chen et al. cannot effectively prevent undetectable on-line password guessing attacks and then proposed an improved approach. Although they actually propose an improved approach, the clients who act as the roles of exchange-message are quite different from the traditional 3PEKE schemes. That is, a client will still act as the intermediate role who exchanges the messages between the other one and server. In other words, both clients will exchange messages with server, individually.
Thus, we propose three approaches, which are called a 3PEKE Protocol with Protected Password Authentication (3PEKE-PPA), an Enhanced 3PEKE Protocol Using Digital Time-Stamp (3PEKE-DTS) and an Enhanced 3PEKE Protocol with Time Bound (3PEKE-TB), to improve the traditional 3PEKE schemes. Our scheme can achieve effectively implement and resist undetectable on-line password guessing attacks and strengthen the 3PEKE system of security.

並列關鍵字

3PEKE ； key exchange protocol ； authentication ； security ； time-stamp ； password ； time bound

參考文獻

[1] M. Abdalla, P.-A. Fouque and D. Pointcheval, “Password-based authenticated key exchange in the three-party setting,” Proceedings of the PKC’05, LNCS, vol. 3386, 2005, pp. 65-84.

[2] M. Abdalla, P.-A. Fouque and D. Pointcheval, “Password-based authenticated key exchange in the three-party setting,” IET Information Security, vol. 153, issue 1, pp. 27-39, 2006.

[3] M. Bellare, S. Halevi, A. Sahai, and S. Vadhan, “Many-to-one trapdoor functions and their relations to public-key cryptosystems,” Proceedings of the CRYPTO'98, of LNCS, vol. 1462, 1998.

[4] C.-C. Chang and Y.-F. Chang, “A novel three-party encrypted key exchange protocol,” Computer Standards & Interfaces, vol. 26, issue 5, pp. 471-476, Sep. 2004.

[5] H.-B. Chen, T.-H. Chen, W.-B. Lee, and C.-C. Chang, “Security enhancement for a three-party encrypted key exchange protocol against undetectable on-line password guessing attacks,” Computer Standards & Interfaces, vol. 30, issue 1-2, pp. 95-99, Jan. 2008.