In the past few years, secure information sharing became very popular in the area of immigration, military applications, healthcare, education, foreign affairs, etc. As secure communication utilizes both wireless and wired communication mechanizations for exchanging sensitive information, so security and privacy of the information exchange cannot be easily compromised. To moderate the security, integrity, authenticity, and privacy issues related to information exchange, numerous authentication mechanisms have been recommended by different researcher in the literature in recent times, but are vulnerable to prospective security flaws such as masquerade, insider, replay, impersonation, password guessing, server spoofing, denial-of-service attacks and in addition failed to deliver mutual authentication. In the past few years, we have also seen a balanced growth in the acceptance of VoIP (Voice over IP) facilities, because the numerous Web and VoIP applications depend on huge and extremely distributed infrastructures to process requests from millions of users in an appropriate manner. Due to their extraordinary desires, these large-scale Internet applications have frequently surrendered security for other objectives such as performance, scalability, and availability. As a result, these applications have characteristically favored weaker, but well-organized security mechanisms in their foundations. Session Initiation Protocol (SIP) is an application and presentation layers signaling protocol that initiates, modifies, and terminates IP-based multimedia sessions. Implementing SIP for secure communication has been a topic of study for the past decade, and several proposals are available in the research domain. However, security aspects are not addressed in most of these proposals, because SIP is exposed to several threats and faces security issue at these layers. Probes for SIP (Session Initiation Protocol) servers have been conveyed for many years, and to gather more details about these activities we simply design a scheme for SIP servers in a network and composed data about some popular attacks. What will follow is an explanation of our interpretations and guidance on how to prevent these attacks from being successful. Biometrics a new field of research has also been materialized in this research, entitled “a three-factor authentication scheme" in which one factor is biometrics. In biometric cryptosystems, the benefits of biometric confirmation are presented to basic cryptographic key supervisory systems to enhance security. Anyhow, this research delivers a general outline of the basics, permitting to biometrics as well as cryptography. This work also gives biometric cryptosystems based on iris biometrics and using smart card as well as a password for authentication
