臺灣博碩士論文加值系統

在許多已提出的代理簽章機章法中，原始簽章者與代理人之間通常需要安全管道，以達成授權代理的目的。為了免除安全管道的要求，學者Zhang提出一個無需安全管道的代理簽章法。不幸的是，Zhang的方法卻產生了安全上的缺失 [6, 16]，因此針對不需要安全管道的需求，首先提出一個安全的個人式代理簽章法。在另一方面，有時因為原始簽章者的權責十分重要，必須授權一代理簽章群，因此有(t, n)門檻式代理簽章法的提出。在已提出的門檻式代理簽章法中，有些方法己經被証明不夠安全，而有些方法則因繁複的設計，導致使用者負荷量十分沈重。於是本論文中提出一套低負荷量的(t, n)門檻式代理簽章法。許多代理簽章法藉由單向雜湊函數的協助，將授權委任書與代理憑證結合成一體。然而大多數的單向雜湊函數並非植基於一些知名與難解的問題假設(諸如離散對數問題、因數分解問題等)，所以使用單向雜湊函數可能削弱代理簽章法的整體安全性，為了改善此一可能的安全性疏失，提出另一套不用單向雜湊函數的代理簽章法。該方法依然保留了無須安全管道的的優點，同時也為代理細節，提供一套強而有力之詳細說明功能。另外，該方法同時對原始簽章者與代理人之間提供了一個公平的保護措施。其實三個新提出代理簽章法，都對代理委任的細節提供了完整的詳細說明功能，藉由此功能與方法的設計巧思，此三個代理簽章法都能讓驗證者追蹤到真正簽發代理簽章的代理人。

Most of the proposed proxy signature schemes need a secure channel between the original signer and the proxy signer. To remove the requirement of secure channels, Zhang proposed his proxy signature scheme without secure channels. However, there is a security disadvantage in Zhang''s scheme [6, 16]. Here an individual proxy signature scheme without secure channel is proposed. To authorize a group of proxy signers, many threshold proxy signature schemes [4, 14, 17, 19] are proposed. Among these schemes, some schemes [19] are not secure while some scheme [14, 17] has heavy overhead. So a threshold proxy signature scheme with light additional load is proposed in this paper. To integrate the warrant into the proxy certificate, both of the two proxy signature schemes use the one-way hash functions. However, the one-way hash functions may weaken the overall of the security of the proxy signature schemes since the security of the most one-way hash functions are not based on the famous cryptographic hard problem. So, a new proxy signature scheme with one-way has functions is proposed. The new scheme also removes the requirement of secure channels and provides the powerful specifiable function for the proxy details. Moreover, the new schemes provide a fair protection both for the original and proxy signers. The three new schemes also have completely specification function for the proxy authorization. In all of the three new schemes, the proxy signers are traceable.

Chapter 1 Introduction …………………………………………. p. 1
Chapter 2 Review of The Past Results …..…………………….. p. 5
2.1 Sun’s (t, n) Threshold Proxy Signature Scheme………….. p. 5
2.2 Zhang’s Proxy Signature Scheme………………………… p. 8
Chapter 3 An Individual Proxy Signature Scheme……………. p. 10
3.1 An Individual Proxy Signature Scheme…………….……. p. 10
3.2 Security Analysis and Discussion…………………………. p. 11
Chapter 4 A (t, n) Threshold Proxy Signature Scheme …….…. p. 14
4.1 A (t, n) Threshold Proxy Signature Scheme……………… p. 14
4.2 Security Analysis and Discussions………………………… p. 17
4.3 Performance Analysis……………………………………… p. 18
Chapter 5 A New Scheme without One-way Hash
Functions …………………………………….…….. p. 22
5.1 Our New Scheme without One-way Hash Functions…… p. 22
5.2 Security Analysis and Discussions………………………… p. 23
Chapter 6 Conclusions…………………………………………… p. 26
References………………………………………………………… p. 28

[1] Chaum, D. and Antwerpen, H. van (1989): "Undeniable Signatures," Crypto ''89, Lecture Notes in Computer Science, Vol. 435, Springer, Berlin, 1990, pp. 212-216.
[2] Harn, L. (1997): " Digital Signature for Diffie-Hellman Public Keys Without Using a One-way Function," Electronics Letters, Vol. 33, No. 2, 1997, pp. 125-126.
[3] Hwang, Sin-Jia and Shi, Chi-Hwai (1999): "The Specifiable Proxy Signature," NCS99, Vol 3, December 1999, pp. 190-197.
[4] Kim, S., Park, S., and Won, D. (1997): "Proxy Signatures," ICICS ’97, Lecture Notes in Computer Science, Vol. 1334, Springer, Berlin, 1997, pp. 223-232.
[5] Knuth, D. (1981): The Art of Computer Programming, Vol. 2: Seminumerical Algorithms, Second Edition, Addison-Wesley, Reading, Mass, 1981, pp. 484-486.
[6] Lee, Narn-Yih, Hwang, Tzonelih, and Wang, Chih Hung (1998): "On Zhang’s Nonrepudiable Proxy Signature Schemes," Third Australasian Conference, ACISP ''98, 1998, pp. 415-422.
[7] MAMBO, Masahiro, USUDA, Keisuke, and OKAMOTO, Eiji (1996a): "Proxy Signatures: Delegation of the Power to Sign Message," IEICE Transaction Fundamentals, Vol. E 79-A, No. 9, September 1996, pp.1338-1354.
[8] MAMBO, Masahiro, USUDA, Keisuke, and OKAMOTO, Eiji (1996b): "Proxy Signatures for Delegation Signing Operation," Proceedings of third ACM Conference on Computer and Communications Security, New Delhi, Mar. 1996, pp. 48-57.
[9] Nechvatal, James (1991): "Public Key Cryptography," in Contemporary Cryptology: The Science of Information Integrity, Simmons, G. J. ed., IEEE Press, Piscatoway, N. J, 1991, pp. 177-288.
[10] Pedersen, T. (1991): "Distributed Proves with Applications to Undeniable Signature," Eurocrypt ''91, Lecture Notes in Computer Science, Vol. 1438, Springer-Verlag, Berlin, 1991, pp. 221-238.
[11] Rabin, M.O.(1979): "Digitalized Signatures and Public Key Functions as Intractable as Factorization," MIT/LCS/TR-212, 1979.
[12] Shimbo, A. (1994): "Multisignature Schemes based on the ElGamal Scheme," Proceedings of 1994 Symposium on Cryptography and Information Security, SCIS94-2C, Japan. 1994.
[13] Stinson, Douglas Robert (1995): "Cryptography: Theory and Practice," CRC Press, Boca Raton, 1995, pp. 330-331.
[14] Sun, Hung-Min (1999): "An Efficient Nonrepudiable Threshold Proxy Signature Scheme with Known Signers," Computer Communications, Vol. 22, 1999, pp. 717-722.
[15] Sun, Hung-Min and Chen, Biing-Jang (1999): "Time-Stamp Proxy Signatures with Traceable Receivers," Proceedings of the Ninth National Conference on Information Security, Taiwan, 1999, pp. 247-253.
[16] Sun, Hung-Min, and Hsieh, Bin-Tsan (1999): "Remark on Two Nonrepudiable Proxy Signature Schemes," Proceedings of the Ninth National Conference on Information Security, Taiwan, 1999, pp. 241-246.
[17] Sun, Hung-Min, Lee, N-Y and Hwang T. (1999): "Threshold Proxy Signatures," IEE Proc.-Computers and Digital Techniques, Vol. 146, No. 5, 1999, pp. 259-263.
[18] Varadharajan, V., Allen, P., and Black, S. (1991): "An Analysis of the Proxy Problem in Distributed Systems," Proceedings of 1991 IEEE Computer Society Symposium on Research m Security and Privacy, 1991, pp. 225-275.
[19] Zhang, K. (1997): "Threshold Proxy Signature Schemes," 1997 Information Security Workshop, Japan, September 1997, pp. 191-197.