Security measures for VoIP application: a state of the art review

Voice over internet protocol (VoIP) is being widely used, while the integration of voice and data provide several opportunities. Lower cost and more flexibility are the main advantages of the VoIP which derived the attention of the enterprises to it. Unfortunately in the other extreme, some security issues may come across with the extensive use of VoIP. The purpose of this review paper is to encourage the VoIP industry to consider the importance of the security matters of their application and to find the gaps by discussing the pros and cons of each application and performing the fair comparison. This article begins by discussing the motivation of security measures in VoIP applications and a list of possible threats such as denial-of-service (DoS), Call Hijacking and Interception. These security issues are the most well known attacks that can be carried out in current VoIP deployment. Next, we discuss about two VoIP applications, which are Skype and GTalk, and their security levels have been measured briefly by highlighting some of the security issues in them. These security measurements are used to perform the comparison between the studied VoIP applications. Finally some methods have been proposed to improve the security in the VoIP applications in future state

SecMon: End-to-End Quality and Security Monitoring System

The Voice over Internet Protocol (VoIP) is becoming a more available and popular way of communicating for Internet users. This also applies to Peer-to-Peer (P2P) systems and merging these two have already proven to be successful (e.g. Skype). Even the existing standards of VoIP provide an assurance of security and Quality of Service (QoS), however, these features are usually optional and supported by limited number of implementations. As a result, the lack of mandatory and widely applicable QoS and security guaranties makes the contemporary VoIP systems vulnerable to attacks and network disturbances. In this paper we are facing these issues and propose the SecMon system, which simultaneously provides a lightweight security mechanism and improves quality parameters of the call. SecMon is intended specially for VoIP service over P2P networks and its main advantage is that it provides authentication, data integrity services, adaptive QoS and (D)DoS attack detection. Moreover, the SecMon approach represents a low-bandwidth consumption solution that is transparent to the users and possesses a self-organizing capability. The above-mentioned features are accomplished mainly by utilizing two information hiding techniques: digital audio watermarking and network steganography. These techniques are used to create covert channels that serve as transport channels for lightweight QoS measurement's results. Furthermore, these metrics are aggregated in a reputation system that enables best route path selection in the P2P network. The reputation system helps also to mitigate (D)DoS attacks, maximize performance and increase transmission efficiency in the network.Comment: Paper was presented at 7th international conference IBIZA 2008: On Computer Science - Research And Applications, Poland, Kazimierz Dolny 31.01-2.02 2008; 14 pages, 5 figure

VoIP: Making Secure Calls and Maintaining High Call Quality

Modern multimedia communication tools must have high security, high availability and high quality of service (QoS). Any security implementation will directly impact on QoS. This paper will investigate how end-to-end security impacts on QoS in Voice over Internet Protocol (VoIP). The QoS is measured in terms of lost packet ratio, latency and jitter using different encryption algorithms, no security and just the use of IP firewalls in Local and Wide Area Networks (LAN and WAN). The results of laboratory tests indicate that the impact on the overall performance of VoIP depends upon the bandwidth availability and encryption algorithm used. The implementation of any encryption algorithm in low bandwidth environments degrades the voice quality due to increased loss packets and packet latency, but as bandwidth increases encrypted VoIP calls provided better service compared to an unsecured environment.Les eines modernes de comunicació multimèdia han de tenir alta seguretat, alta disponibilitat i alta qualitat de servei (QoS). Cap tipus d¿implementació de seguretat tindrà un impacte directe en la qualitat de servei. En aquest article s¿investiga com la seguretat d'extrem a extrem impacta en la qualitat de servei de veu sobre el Protocol d'Internet (VoIP). La qualitat de servei es mesura en termes de pèrdua de proporció de paquets, latència i jitter utilitzant diferents algoritmes d¿encriptació, sense seguretat i només amb l'ús de tallafocs IP en local i en xarxes d'àrea àmplia (LAN i WAN). Els resultats de les proves de laboratori indiquen que l'impacte general sobre el rendiment de VoIP depèn de la disponibilitat d'ample de banda i l'algorisme de xifrat que s'utilitza. La implementació de qualsevol algorisme de xifrat en entorns de baix ample de banda degrada la veu a causa de l'augment de la pèrdua de paquets i latència dels paquets de qualitat, però quan l'ample de banda augmenta les trucades de VoIP xifrades proporcionen un millor servei en comparació amb un entorn sense seguretat.Las herramientas modernas de comunicación multimedia deben tener alta seguridad, alta disponibilidad y alta calidad de servicio (QoS). Ningún tipo de implementación de seguridad tendrá un impacto directo en la calidad de servicio. En este artículo se investiga como la seguridad de extremo a extremo impacta en la calidad de servicio de voz sobre el Protocolo de Internet (VoIP). La calidad de servicio se mide en términos de pérdida de proporción de paquetes, latencia y jitter utilizando diferentes algoritmos de encriptación, sin seguridad y sólo con el uso de cortafuegos IP en local y en redes de área amplia (LAN y WAN). Los resultados de las pruebas de laboratorio indican que el impacto general sobre el rendimiento de VoIP depende de la disponibilidad de ancho de banda y el algoritmo de cifrado que se utiliza. La implementación de cualquier algoritmo de cifrado en entornos de bajo ancho de banda degrada la voz debido al aumento de la pérdida de paquetes y latencia de los paquetes de calidad, pero cuando el ancho de banda aumenta las llamadas de VoIP cifradas proporcionan un mejor servicio en comparación con un entorno sin seguridad

Taxonomy of P2P Applications

Peer-to-peer (p2p) networks have gained immense popularity in recent years and the number of services they provide continuously rises. Where p2p-networks were formerly known as file-sharing networks, p2p is now also used for services like VoIP and IPTV. With so many different p2p applications and services the need for a taxonomy framework rises. This paper describes the available p2p applications grouped by the services they provide. A taxonomy framework is proposed to classify old and recent p2p applications based on their characteristics

The voice activity detection (VAD) recorder and VAD network recorder : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Computer Science at Massey University

The project is to provide a feasibility study for the AudioGraph tool, focusing on two application areas: the VAD (voice activity detector) recorder and the VAD network recorder. The first one achieves a low bit-rate speech recording on the fly, using a GSM compression coder with a simple VAD algorithm; and the second one provides two-way speech over IP, fulfilling echo cancellation with a simplex channel. The latter is required for implementing a synchronous AudioGraph. In the first chapter we introduce the background of this project, specifically, the VoIP technology, the AudioGraph tool, and the VAD algorithms. We also discuss the problems set for this project. The second chapter presents all the relevant techniques in detail, including sound representation, speech-coding schemes, sound file formats, PowerPlant and Macintosh programming issues, and the simple VAD algorithm we have developed. The third chapter discusses the implementation issues, including the systems' objective, architecture, the problems encountered and solutions used. The fourth chapter illustrates the results of the two applications. The user documentations for the applications are given, and after that, we analyse the parameters based on the results. We also present the default settings of the parameters, which could be used in the AudioGraph system. The last chapter provides conclusions and future work

Secure covert communications over streaming media using dynamic steganography

Streaming technologies such as VoIP are widely embedded into commercial and industrial applications, so it is imperative to address data security issues before the problems get really serious. This thesis describes a theoretical and experimental investigation of secure covert communications over streaming media using dynamic steganography. A covert VoIP communications system was developed in C++ to enable the implementation of the work being carried out. A new information theoretical model of secure covert communications over streaming media was constructed to depict the security scenarios in streaming media-based steganographic systems with passive attacks. The model involves a stochastic process that models an information source for covert VoIP communications and the theory of hypothesis testing that analyses the adversary‘s detection performance. The potential of hardware-based true random key generation and chaotic interval selection for innovative applications in covert VoIP communications was explored. Using the read time stamp counter of CPU as an entropy source was designed to generate true random numbers as secret keys for streaming media steganography. A novel interval selection algorithm was devised to choose randomly data embedding locations in VoIP streams using random sequences generated from achaotic process. A dynamic key updating and transmission based steganographic algorithm that includes a one-way cryptographical accumulator integrated into dynamic key exchange for covert VoIP communications, was devised to provide secure key exchange for covert communications over streaming media. The discrete logarithm problem in mathematics and steganalysis using t-test revealed the algorithm has the advantage of being the most solid method of key distribution over a public channel. The effectiveness of the new steganographic algorithm for covert communications over streaming media was examined by means of security analysis, steganalysis using non parameter Mann-Whitney-Wilcoxon statistical testing, and performance and robustness measurements. The algorithm achieved the average data embedding rate of 800 bps, comparable to other related algorithms. The results indicated that the algorithm has no or little impact on real-time VoIP communications in terms of speech quality (< 5% change in PESQ with hidden data), signal distortion (6% change in SNR after steganography) and imperceptibility, and it is more secure and effective in addressing the security problems than other related algorithms