Authentication is the first and most important step in provision of any secure service to the users. It is used to ensure that only authentic users be able to use that secure service.Anonymous authentication is another vital aspect in wireless secure communication. Anonymous authentication is termed as authenticating the user without disclosing his/her identity. Many authentication with anonymity schemes are propose for secure communication in wireless environment. Wireless communication technology is susceptible to many common attacks. In this paper we point out security flaws in recently proposed improved anonymous authentication schemes in wireless communication, in which the inside adversary who register as a legitimate user reveals the identity of user and thus defeat the anonymity. We propose a modified anonymous authentication scheme with enhanced security, covering the security flaws identified in recent schemes.