SIP message authentication and SRTP key agreement are the important issue in the SIP-based VoIP service. Several secure solutions such as HTTP Digest Authentication, SSL/TLS, and S/MIME, are used for the SIP message authentication and key agreement. When the VoIP is used in the wireless environments, the efficiency of security service is one of the important matters in question. Therefore, we w...

SIP message authentication and SRTP key agreement are the important issue in the SIP-based VoIP service. Several secure solutions such as HTTP Digest Authentication, SSL/TLS, and S/MIME, are used for the SIP message authentication and key agreement. When the VoIP is used in the wireless environments, the efficiency of security service is one of the important matters in question. For the such ef...

Today Voice over Internet Protocol (VoIP) is used in large scale to deliver voice and multimedia over the packet data networks, such as the Internet. The Session Initiation Protocol (SIP) is widely used as a signalling protocol for VoIP. As SIP is being used more, the security of it is an important issue. In this paper, we concentrate on user authentication in SIP. We examine current solutions ...

Voice over IP (VoIP) is an alternative to traditional circuit-switched telephony that allows human voice and video to travel over existing packet data networks along with traditional data packets. H.323 and SIP are the two standard protocols used today for signaling and call control in VoIP, and they are essential for providing total access and for supporting IP-based services. In order to prov...

Voice over IP (VoIP) services based on the Session Initiation Protocol (SIP) gain ground as compared to other protocols like MGCP or H.323. However, the open SIP architecture constitutes the provided services vulnerable to various attacks, similar to those currently existing in Internet. The lack of a formal way to describe VoIP vulnerabilities hinders the development of tools that could be uti...

With the appearance of new Internet services like Voice over IP and IP television, malwares are in the way to update and extend their targets. In this paper, we discuss the emergence of a new generation of malwares attacking VoIP infrastructures and services. Such malwares constitute a real threat to the currently deployed VoIP architectures without strong security measures in place. We present...

Spam over internet telephony (SPIT) refers to all unsolicited and massive scale attempts to establish voice communication with oblivious users of voice over internet protocol (VoIP) services. SPIT exhibits a significant increase over the last years, thus developing into a serious threat with adverse impact and costs for the business economy. An audio completely automated public Turing test to t...

Current Voice over IP (VoIP) services are regarded less secure than the traditional public switched telephone network (PSTN). This is due to the fact that VoIP services are frequently deployed in an relatively open environment, so that VoIP infrastructures can be easily accessed by potential attackers. Furthermore, current VoIP services heavily rely on other public Internet infrastructures shar...

Multimedia communications over IP are booming as they offer higher flexibility and more features than traditional voice and video services. IP telephony known as Voice over IP (VoIP) is one of the commercially most important emerging trends in multimedia communications over IP. Due to the flexibility and descriptive power, the Session Initiation Protocol (SIP) is becoming the root of many sessi...