具有最佳簽章者匿名性與強指定驗證者之弱鏈結性環簽章法

A Strong Designated-Verifier Weak Linkable Ring Signature Scheme for Strongest Signer Anonymity

向胤澤(Yin-Ze Siang)

指導教授 ： 黃心嘉

淡江大學/工學院/資訊工程學系碩士班/碩士(2011年)

https://doi.org/10.6846/TKU.2011.00723

摘要

為了方便於匿名性的應用上，陳等學者的具有鏈結性之指定驗證者環簽章法提供n位環成員分之一的簽章者匿名性。該簽章法的計算成本和參加計算的環成員人數呈正比。對於簽章者匿名性而言，最佳的簽章者匿名性應是隱身於所有合法的使用者中；為最佳的簽章者匿名性， 所有合法的使用者人數n通常是非常大的，因此提供最佳的簽章者匿名性時，陳等學者的方法效率並非有效方法。另外，陳等學者的方法中所含的強鏈結性會傷害到環簽章的簽章者匿名性。為了有效地提供最佳的簽章者匿名性以及移除強鏈結性對簽章者匿名性的傷害，我們提出了具有最佳簽章者匿名性與強指定驗證者之弱鏈結性環簽章法。在計算成本的分析上，我們的方法比陳等學者的方法有效。在簽章者匿名性上，我們的方法也比陳等學者的方法強。另外，為了防止訊息洩漏與身分相關敏感資料，我們也提供了具有最佳簽章者匿名性與強指定驗證者之弱鏈結性環簽密法。最後，我們的兩篇方法均有正式的安全性證明。

關鍵字

環簽章 ； 環簽密 ； 強指定驗證者 ； 簽章者匿名性 ； 鏈結性

並列摘要

For the anonymous applications, Chen et al. proposed a designated-verifier linkable ring signature scheme with “one-out-of-n” signer anonymity, where n is the number of ring members. In their scheme, the computational cost of each designated-verifier linkable ring signature is proportional to n. The maximum signer anonymity should be one-out-of-maximum anonymity that each one is hidden among all possible users, so n should be the total number of users. Due to the computational cost, Chen et al.’s scheme is an inefficient solution when n is very large. Moreover, the strong linkability also damages the signer anonymity. To efficiently provide one-out-of-maximum signer anonymity and remove the damage caused by strong linkability, our strong designated-verifier weak-linkable ring signature scheme is proposed. Due to the performance analysis, our scheme is more efficient than Chen et al.’s scheme, although our signer anonymity is stronger than Chen et al.’s signer anonymity. Moreover, the message may leak some sensitive identity data, this thesis also proposed a strong designated-verifier weak-linkable ring signcryption scheme to provide indistinguishable message confidentiality. Moreover, our security properties are proved in the random oracle model.

並列關鍵字

Ring signature ； ring signcryption ； strong designated verifier ； signer anonymity ； linkability

參考文獻

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