For many years, the pay-TV system has attracted a lot of users. Users have recently expressed the desire to use mobile TV or mobile payment via anonymous protocols. The mobile users have also received their services over cellular communications networks. Each mobile device receives services from each head end systems. With increasing numbers of users and the expansion of Internet, user’s privacy has become crucial important. When a device leaves the head end system’s range, it must receive services from another head end system. In this paper, we review ’s scheme and we highlight some weaknesses, including privilege insider attack and user traceability attack. Finally, we alleviate the scheme and analyze the alleviated scheme using both heuristic and formal methods.
Recently, remote user authentication schemes are implemented on elliptic curve cryptosystem (ECC) to reduce the computation loads for mobile devices. However, most remote user authentication schemes on ECC are based on public-key cryptosystem, in which the public key in the system requires the associated certificate to prove its validity. Thus, the user needs to perform additional computations to verify the certificate in these schemes. In addition, we find these schemes do not provide mutual authentication or a session key agreement between the user and the remote server. Therefore, we propose an ID-based remote mutual authentication with key agreement scheme on ECC in this paper. Based upon the ID-based concept, the proposed scheme does not require public keys for users such that the additional computations for certificates can be reduced. Moreover, the proposed scheme not only provides mutual authentication but also supports a session key agreement between the user and the server. Compared with the related works, the proposed scheme is more efficient and practical for mobile devices. With the integration of wireless communication and pay-TV, mobile broadcast TV technologies have advanced noticeably in recent years. In 2011, proposed an efficient anonymous authentication protocol for mobile pay-TV and claimed that their protocol is secure and efficient. However, Kim showed that their protocol has weaknesses in password guessing attack and impersonation attack with the assumption that attacker could get user’s smart card. Thereby, this paper proposes an anonymous authentication protocol to solve the flaws in ’s protocol. Authenticated key agreement protocols play an important role for network-connected servers to authenticate remote users in Internet environment. In recent years, several authenticated key agreement protocols for single-server environment have been developed based on chaotic maps. In modern societies, people usually have to access multiple websites or enterprise servers to accomplish their daily personal matters or duties on work; therefore, how to increase user's convenience by offering multi-server authentication protocol becomes a practical research topic. In this study, a novel chaotic map-based anonymous multi-server authenticated key agreement protocol using smart card is proposed. In this protocol, a legal user can access multiple servers using only a single secret key obtained from a trusted third party, known as the registration center. Security analysis shows this protocol is secure against well-known attacks. In addition, protocol efficiency analysis is conducted by comparing the proposed protocol with two recently proposed schemes in terms of computational cost during one authentication session. We have shown that the proposed protocol is twice faster than the one proposed by Khan and He while preserving the same security properties as their protocol has. Copyright © 2014 John Wiley & Sons, Ltd. In terms of convenience requirements, mobility has been one of the most important services for pay-TV systems. In 2009, Yang and Chang proposed an authentication protocol for mobile devices using elliptic curves cryptography (ECC) and claimed that their mechanism is secure and efficient using in mobile pay-TV systems. In this paper, we demonstrate that their protocol still is insecure for authentication without password protection and performs inefficiently. Therefore, we offer an anonymous authentication protocol (AAP) to solve the performance issue and insecure risks. In addition, we present an analysis of our protocol to show that our protocol suits better for applications with higher security requirements and low power-consuming devices. Generally, if a user wants to use numerous different network services, he she must register himself herself to every service providing server. It is extremely hard for users to remember these different identities and passwords. In order to resolve this problem, various multi-server authentication protocols have been proposed. Recently, analyzed Hsiang and Shih's multi-server authentication protocol and proposed an improved dynamic identity based authentication protocol for multi-server architecture. They claimed that their protocol provides user's anonymity, mutual authentication, the session key agreement and can resist several kinds of attacks. However, through careful analysis, we find that 's protocol is still vulnerable to leak-of-verifier attack, stolen smart card attack and impersonation attack. Besides, since there is no way for the control server CS to know the real identity of the user, the authentication and session key agreement phase of 's protocol is incorrect. We propose an efficient and security dynamic identity based authentication protocol for multi-server architecture that removes the aforementioned weaknesses. The proposed protocol is extremely suitable for use in distributed multi-server architecture since it provides user's anonymity, mutual authentication, efficient, and security. In 2014, Choi proposed a security enhanced anonymous multi-server authenticated key agreement scheme using smart card and biometrics and claimed that their scheme could overcome all of security issues in Chuang-Chen's scheme, such as impersonation attack, smart card loss attack, denial of service attack and perfect forward secrecy. Unfortunately, we discover that Choi's proposed scheme is not only still vulnerable to smart card loss attack and lack of perfect forward secrecy, but also contains a flaw in design for authentication phase after our analysis in detail. In order to solve these security issues, we propose an enhanced secure anonymous authentication scheme with key agreement based on smart cards and biometrics for multi-server environments in this paper. According to our performance and security analysis, it can prove that our proposed scheme is more efficiency and security in comparison to previous schemes.