对三个多服务器环境下匿名认证协议的分析

设计安全高效的多服务器环境下匿名身份认证协议是当前安全协议领域的研究热点。基于广泛接受的攻击者模型，对多服务器环境下的三个代表性匿名认证协议进行了安全性分析.指出Wan等协议无法实现所声称的离线口令猜测攻击，且未实现用户匿名性和前向安全性；指出Amin等协议同样不能抵抗离线口令猜测攻击，且不能提供匿名性，对两种破坏前向安全性的攻击是脆弱的；指出Reedy等协议不能抵抗所声称的用户仿冒攻击和离线口令猜测攻击，且无法实现用户不可追踪性.突出强调这些协议失败的根本原因在于，违反协议设计的三个基本原则：公钥原则、用户匿名性原则和前向安全性原则.明确协议的具体失误之处，并提出相应修正方法.

Crytanalysis of Three Anonymous Authentication Schemes for Multi-Server Environment

The design of secure and efficient user authentication protocols for multi-serverenvironment is increasingly becoming a hot research topic in the cryptographic protocol community. Based on the widely acceptedadversarymodel, this paperanalyzes threerepresentative, recently proposed user authentication schemes for multi-server environment. We point out that:1) Wan et al.''s scheme is subject to offline password guessing attack as opposed to the authors'' claim and it also cannot provide user anonymity and forward secrecy. 2) Amin et al.''s scheme cannot withstand offline password guessing attack, cannot preserve user anonymity and is vulnerable to two kinds of forward secrecy issues. 3) Reedy et al.''s scheme cannot resist againstuser impersonation attack and offline password guessing attack as well as falling short of user un-traceability. We highlight three principles for designing more robust anonymous multi-factor authentication schemes:public key principle, user anonymity principle and forward secrecy principle, explaining the essential reasons for the security flaws of the above protocols. We further propose someadmendments for the identified security flaws.