在現今這個網路發達的世界裡，由於資訊大多是被公開的且容易被取得，因此為了保障一些重要的資訊，人們往往會採取許多的安全措施，其中又以密碼確認及協商鑰匙建立這兩種技術為最為常見。首先以密碼確認技術來說，在2005年時Yang和Wang兩人提出了一個結合晶片卡的密碼確認流程來確保遠端使用者的認證安全。不過他們的架構卻存在著安全上的弱點，也就是無法阻擋攻擊者的主動偽裝攻擊。而當確認完身分之後，就可以再運用鑰匙建立技術來協商出一把通訊用的鑰匙，以供之後彼此通訊時使用。而在2003年時Boyd 和Mao兩人也發展了一個以橢圓曲線為主的鑰匙建立流程來保障安全的傳輸。然而，此方法也同樣存在著一些安全上的缺陷，就是容易遭受鑰匙遺失的假裝攻擊。 因此，在本篇論文我們將個別的分析Yang和Wang及Boyd 和Mao等人的架構，指出其安全上的缺陷，並針對偽裝攻擊及鑰匙遺失的假裝攻擊來提出攻擊的演算法，最後更進一步的對遭受偽裝攻擊的Yang和Wang之密碼確認流程提出改進的方法，以增加其可信性。 Because most of information is public and acquired easily in this network fast-developing world, people usually take many safety measures to protect the important information. The password authentication and key establishment are the two most common technologies. At first, in the method of password authentication, Yang and Wang proposed password schemes with smart card to assure legal users can login in and access the resource of the server in 2005. But their schemes are vulnerable to an active attacker who will take forgery attack. After authenticating the identity, user then can make use of key establishment technology to establish the session key for follow communication. Boyd and Mao proposed key establishment protocols using elliptic curve pairings for Internet protocols in 2003. However, their protocols are also vulnerable to key-Compromise Impersonation attack. We will take cryptanalysis of Yang–Wang schemes and Boyd-Mao protocols and propose forgery attack algorithm for Yang–Wang schemes and key-Compromise Impersonation attack algorithm for Boyd-Mao protocols. Then we further improve the Yang–Wang schemes and make them be able to against forgery attack.
