基于切比雪夫混沌映射和生物识别的身份认证方案

云计算中访问控制和安全性是两大问题，且与传统的身份认证存在一定区别。利用切比雪夫多项式的半群特性、混沌特性，提出了一种基于切比雪夫混沌映射和生物识别的口令认证密钥协商方案。用户和服务器首先在云服务提供商（CSP）处进行注册，随后无需CSP的参与即可完成认证，建立会话密钥。安全性分析和性能比较表明，方案满足许多安全因素，如双向认证、用户隐私保护、多因素安全、前向安全性，即使CSP的主密钥被泄露，前向安全性也能确保用户会话密钥的机密性；此外，方案还能抵抗中间人攻击、离线口令猜测攻击和仿冒攻击等，并且支持多服务器环境中用户口令和生物特征的高效变更。 

A biometric verification based authentication scheme using Chebyshev chaotic mapping

In cloud computing, access control and security are two major problems, and there are some differences from traditional identity authentication. Inspired by the semi-group and chaotic properties of Chebyshev polynomials, a scheme of password-authenticated key agreement using Chebyshev chaotic mapping and biometrics has been presented. In the proposed model, the users and the servers need to register at the cloud service provider (CSP) in the beginning. Then they can complete authentication and establish session key without the participation of CSP. Moreover, security analysis and performance comparison show that the proposed scheme satisfies many security factors, such as mutual authentication, user privacy protection, multi-factor security and forward security. Forward security assures the confidentiality of the user's session key, even if the private key of the CSP is compromised. The proposed scheme is also robust to resist man-in-the-middle attacks, off-line password guessing and impersonation attacks, etc. In addition, it supports efficient changes to user passwords and biometric characteristics in a multi-server environment.