Secure Voice-over-IP

Voice-over-IP (VoIP) is one of the main applications or services, which dramatically increased the spread and usage of the Internet. VoIP describes the transmission and reception of voice and video data over networks that use the “internet protocol” (IP) as transport protocol. With the use of VoIP within company networks (intranet) investors hope to reduce the expenses for infrastructure and maintenance, because telephony and data networks will no longer be separated. The often-used term “internet telephony” describes the transport medium for VoIP, which will in this case be the Internet. Based on the widespread availability of broadband Internet access, VoIP is becoming more and more a cheap alternative to conventional telephone networks. The main drawback of VoIP is that there is no reliable authentication of the calling parties as well as no methods to prevent trace and capture of calls. Thus, with simply methods and low effort VoIP calls can be recorded. This fact leads to the idea to develop a VoIP communication software which offers secure and confidential communication. The details of design and implementation of this software as well as the chosen specifications are described in this paper.