| 摘要: | 遠端使用者身分認證是資訊安全中最重要的議題之一，伺服器端能透過身分認證過濾非法的使用者，使合法的使用者能夠存取遠端服務。以通行碼為基礎之身分認證機制是目前最常被使用在網際網路上的方法。在單次通行碼機制中，使用者每次登錄時所使用的通行碼是動態改變的。本論文之目的在於提出一個單次通行碼機制，其對使用者來說具有計算量及儲存空間高效率性，登錄驗證回合數最簡化，並且無須進行時戳同步之特性。我們重新造訪了基於挑戰-回應技巧之Schnorr身分認證機制，我們發現了重複使用挑戰值的技巧以應用在單次通行碼機制中。在本論文中，我們提出兩個基於Schnorr身分認證之單次通行碼機制。第一個機制提供了單向認證，並且能抵抗重送攻擊、暴力攻擊、偽冒攻擊、驗證碼竊取攻擊、驗證表竄改攻擊以及伺服器入侵攻擊。此外，此機制也適合應用在智慧卡登錄系統中。第二個機制提供了雙向認證與會議金鑰產生協議，並且能抵抗重送攻擊、暴力攻擊、偽冒攻擊、中間人攻擊、反射攻擊以及平行會期攻擊。;Authentication ensures that servers′ services can only be obtained by legitimate users.
The password-based authentication scheme is regarded as one of the most generally used methods of authentication on the internet. In one-time password authentication schemes, users′ passwords are dynamically changed in each user login. The purpose of this thesis is to propose a secure and practical one-time password scheme that is computation efficient, storage efficient, interaction minimization, and time-stamp synchronization free for the prover. We revisit the challenge-response based Schnorr identification protocol. Our idea comes from reusing a challenge with different commitments in the Schnorr identification protocol, and we also give a brief security analysis to explain why this kind of challenge-reused version is secure. In this thesis, two one-time password schemes based on this modified Schnorr identification protocol are proposed. The preliminary scheme provides unilateral authentication and can resist the replay attack, brute force attack, impersonation attack, stolen verifier attack, verification-table tampering attack, and server compromise attack. In addition, this scheme is practical for smart card applications. The enhanced scheme provides mutual authentication and session key agreement, and it can resist the replay attack, impersonation attack, brute force attack, man-in-the-middle attack, reflection attack, and parallel session attack. |
