Voice over Internet Protocol (VoIP) is a general term for a family of transmission technologies to delivery of voice communications over IP networks such as the Internet or other packet-switched networks. VoIP systems employ session control protocols to control the set-up and tear-down of calls as well as audio codecs which encode speech allowing transmission over an IP network as digital audio...

In Voice over Internet Protocol (VoIP) system, the speech signal is degraded when passed through the network layers, since the best effort policy based IP network leads to the network degradations including delay, packet loss jitter. The transmission of voice over internet protocols requires signal processing for reliable & efficient performance over the communication platform. The work in this...

Spam over Internet Telephony as the distribution of unwanted voice messages over Voice over Internet Protocol networks is an upcoming threat. It is harder to prevent than e-mail spam since its content is not available before the victim is annoyed. This is even more difficult if the spam is sent directly to the victim’s user equipment, bypassing the proxies of the service provider. Hence, this m...

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...

We present a concept to achieve non-repudiation for natural language conversations over the Internet. The method rests on chained electronic signatures applied to pieces of packet-based, digital, voice communication. It establishes the integrity and authenticity of the bidirectional data stream and its temporal sequence and thus the security context of a conversation. The concept is close to th...

Due to the growing demand for VoIP (Voice over Internet Protocol) services, researches on VoIP design have attained more and more attention. Compared with a traditional voice service PSTN (Public Switched Telephony Network), VoIP is able to provide lower cost and more flexibility. However, there are still many challenging issues to guarantee a consistent and good quality of voice connection ove...

For some forms of communication, people prefer to communicate using their voices rather than typing. By permitting voicemail to be implemented in an interoperable way on top of Internet Mail, voice messaging and electronic mail no longer need to remain in separate, isolated worlds, and users will be able to choose the most appropriate form of communication. This will also enable new types of de...

Voice networks evolved from the fixed traditional telephone system, to mobile and wireless networks and now towards a converged voice and data infrastructure. This convergence is based on the spread of the Internet Protocol, where VoIP is developing. Due to IP network characteristics, hackers are able to compromise and take control of different aspects of IP telephony such as signaling informat...

We examine relationships among Internet diffusion, voice and accountability, and government corruption based on data from 24 Latin American and 23 sub-Saharan African countries from 2006 to 2010. Our study suggests that greater levels of Internet diffusion are associated with greater levels of voice and accountability and that greater levels of voice and accountability are associated with lower...