認證機制與權利委託機制之隱私強化及效能提升;Privacy and Efficiency Enhancement of Authentication and Delegation Control

NCUIR > College of Electrical Engineering & Computer Science > Graduate Institute of Computer Science and Information Engineering > Electronic Thesis & Dissertation > Item 987654321/77493

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/77493

Title:	認證機制與權利委託機制之隱私強化及效能提升;Privacy and Efficiency Enhancement of Authentication and Delegation Control
Authors:	郭宗閔;Kuo, Tsung-Min
Contributors:	資訊工程學系
Keywords:	會員資格認證;匿名憑證;動態反向累積器;代理人重加密;零知識證明;Membership Authentication;Anonymous Credential;Dynamic Reversed Accumulator;Proxy Re-encryption;Zero-knowledge Proofs
Date:	2018-06-19
Issue Date:	2018-08-31 14:45:50 (UTC+8)
Publisher:	國立中央大學
Abstract:	認證機制 (authentication) 一直以來都是受關注的議題，然而使用者在與服務提供者互動過程中可能會洩漏其隱私，使得使用者必須承受被心懷不軌的服務提供者追蹤或是假冒的風險。雖然已經有許多會員資格 (membership) 認證與授權之隱私強化保護機制被提出，但這些機制受限於運算複雜度或是安全性上的考量，只能流於形式卻未必實用。此外，代理人重加密系統 (proxy re-encryption systems) 的研究中，有關金鑰揭露攻擊和未經授權的重加密等安全性議題及系統運算效能提升之挑戰，在過去幾年也有非常廣泛的討論。本論文將對前述的幾個系統及應用情節進行討論，並且提出相對應的解決方案。本論文的研究分成兩部分：第一部分是有關會員資格的認證與授權；而第二部分則是在代理人重加密系統中進行完善的權利委託控管。在會員資格認證的研究中，匿名憑證系統 (anonymous credential system) 和會員資格認證系統 (membership authentication system) 是兩個具代表性的認證機制：使用者可利用零知識證明 (zero-knowledge proof) 技術向驗證者證明其擁有憑證或會員資格的合法性；但驗證者在驗證憑證或會員資格正確性的過程中卻無法得知使用者的真實身分。然而，此機制需要進行大量複雜的密碼計算，本論文會針對此兩個系統提出相對應的效能提升的研究成果。而動態累積系統 (dynamic accumulator) 是有關會員資格授權研究中一個重大的發明，使得管理者可以更簡單地針對每個會員的資格有效性進行管理，並且可以針對不同的群組進行不同服務存取的權力授權。然而，此系統卻可能發生合法的會員憑證遭到假冒的攻擊，本論文會針對此研究提出一個更安全但卻更有效率的研究成果。另外，透過本論文的研究發現，假如每個重加密後之密文可以綁定一個特定的權限，那麼委託者 (delegator) 透過代理人 (proxy) 的幫助就可以指定某個密文可被解密的被委託者 (delegatee) 身分，以此達到限制每把重加密金鑰 (re-encryption key) 可應用範圍以及管理所有可取得重加密密文對象的目的。值得注意的是，此研究成果除了提供有彈性地進行重加密權利委託之隱私強化存取控管，更提供針對原密文與重加密後之密文一體適用的解密演算法 (universal decryption);而且保證系統在面對選擇密文攻擊 (chosen-ciphertext attack) 時的不可分辨性 (indistinguishability)。 ;The debate on the issue of access control in literature is always enthusiastic and will never be suspended. Because the information provided by users during interaction with service providers may undermine their privacy. The users must risk being traced or even impersonated by corrupt service providers. Many recent authentication and authorization mechanisms of memberships are introduced to enrich the protection of privacy. Nevertheless, these mechanisms do not apply directly, because the defects regarding computational complexity and security. Besides, the security issues of key exposure attack and unauthorized re-encryption and the performance challenges have been extensively considered in proxy re-encryption systems for years. In this dissertation, not only the aforementioned mechanisms and its application scenarios are mentioned and discussed but also the corresponding countermeasures are proposed. The research orientation of this dissertation can be divided into two parts in substance: one is authentication and authorization of memberships; and the other one is flexible delegation control in proxy re-encryption systems. For the part of membership authentication, anonymous credential systems and membership authentication systems are two common mechanisms. A user can prove to a verifier that he or she has been given an appropriate credential or membership in zero-knowledge. The verifier can verify the validity of the credential or membership while learning nothing about the user′s real identity. However, existing solutions consist of complicated cryptographic computations, thus, two efficiency-enhanced approaches are suggested for individual systems. For the part of membership authorization, dynamic accumulator is an important invention in which the authority can simply administer each member′s access right and provide differential services for individual groups. However, existing solutions are vulnerable to membership certificate impersonation. The suggested dynamic reversed accumulator can withstand this attack and performs more efficiently. In addition, for the part of flexible delegation control, our research shows that if each of the re-encrypted ciphertexts is bound to a specific grant; the delegator can decide which of his or her ciphertexts can later be decrypted by a designated delegatee with the help of a semi-trusted proxy. In this way, the power of the re-encryption key is restrained and the re-encryption of all ciphertexts can be handled by the delegator. The suggested ID-based proxy re-encryption system provides a practical solution which has the advantages of flexible delegation control and universal decryption; and guarantees the system supply indistinguishability against chosen-ciphertext attack.
Appears in Collections:	[Graduate Institute of Computer Science and Information Engineering] Electronic Thesis & Dissertation

Files in This Item:

File	Description	Size	Format
index.html		0Kb	HTML	102	View/Open

社群 sharing

Loading...