Delivering Live Multimedia Streams to Mobile Hosts in a Wireless Internet with Multiple Content Aggregators

We consider the distribution of channels of live multimedia content (e.g., radio or TV broadcasts) via multiple content aggregators. In our work, an aggregator receives channels from content sources and redistributes them to a potentially large number of mobile hosts. Each aggregator can offer a channel in various configurations to cater for different wireless links, mobile hosts, and user preferences. As a result, a mobile host can generally choose from different configurations of the same channel offered by multiple alternative aggregators, which may be available through different interfaces (e.g., in a hotspot). A mobile host may need to handoff to another aggregator once it receives a channel. To prevent service disruption, a mobile host may for instance need to handoff to another aggregator when it leaves the subnets that make up its current aggregator�s service area (e.g., a hotspot or a cellular network).\ud In this paper, we present the design of a system that enables (multi-homed) mobile hosts to seamlessly handoff from one aggregator to another so that they can continue to receive a channel wherever they go. We concentrate on handoffs between aggregators as a result of a mobile host crossing a subnet boundary. As part of the system, we discuss a lightweight application-level protocol that enables mobile hosts to select the aggregator that provides the �best� configuration of a channel. The protocol comes into play when a mobile host begins to receive a channel and when it crosses a subnet boundary while receiving the channel. We show how our protocol can be implemented using the standard IETF session control and description protocols SIP and SDP. The implementation combines SIP and SDP�s offer-answer model in a novel way

Options for Securing RTP Sessions

The Real-time Transport Protocol (RTP) is used in a large number of different application domains and environments. This heterogeneity implies that different security mechanisms are needed to provide services such as confidentiality, integrity, and source authentication of RTP and RTP Control Protocol (RTCP) packets suitable for the various environments. The range of solutions makes it difficult for RTP-based application developers to pick the most suitable mechanism. This document provides an overview of a number of security solutions for RTP and gives guidance for developers on how to choose the appropriate security mechanism

Session Initiation Protocol Attacks and Challenges

In recent years, Session Initiation Protocol (SIP) has become widely used in current internet protocols. It is a text-based protocol much like Hyper Text Transport Protocol (HTTP) and Simple Mail Transport Protocol (SMTP). SIP is a strong enough signaling protocol on the internet for establishing, maintaining, and terminating session. In this paper the areas of security and attacks in SIP are discussed. We consider attacks from diverse related perspectives. The authentication schemes are compared, the representative existing solutions are highlighted, and several remaining research challenges are identified. Finally, the taxonomy of SIP threat will be presented

Efficient and flexible password authenticated key agreement for Voice over Internet Protocol session initiation protocol using smart card

Providing a suitable key agreement protocol for session initiation protocol is crucial to protecting the communication among the users over the open channel. This paper presents an efficient and flexible password authenticated key agreement protocol for session initiation protocol associated with Voice over Internet Protocol. The proposed protocol has many unique properties, such as session key agreement, mutual authentication, password updating function and the server not needing to maintain a password or verification table, and so on. In addition, our protocol is secure against the replay attack, the impersonation attack, the stolen-verifier attack, the man-in-the-middle attack, the Denning–Sacco attack, and the offline dictionary attack with or without the smart card

Robust and efficient password authenticated key agreement with user anonymity for session initiation protocol-based communications

A suitable key agreement protocol plays an essential role in protecting the communications over open channels among users using Voice over Internet Protocol (VoIP). This paper presents a robust and flexible password authenticated key agreement protocol with user anonymity for Session Initiation Protocol (SIP) used by VoIP communications. Security analysis demonstrates that our protocol enjoys many unique properties, such as user anonymity, no password table, session key agreement, mutual authentication, password updating freely and conveniently revoking lost smartcards etc. Furthermore, our protocol can resist the replay attack, the impersonation attack, the stolen-verifier attack, the man-in-middle attack, the Denning-Sacco attack, and the offline dictionary attack with or without smartcards. Finally, performance analysis shows that our protocol is more suitable for practical application in comparison with other related protocols

An energy efficient authenticated key agreement protocol for SIP-based green VoIP networks

Voice over Internet Protocol (VoIP) is spreading across the market rapidly due to its characteristics such as low cost, flexibility implementation, and versatility of new applications etc. However, the voice packets transmitted over the Internet are not protected in most VoIP environments, and then the user’s information could be easily compromised by various malicious attacks. So an energy-efficient authenticated key agreement protocol for Session Initial Protocol (SIP) should be provided to ensure the confidentiality and integrity of data communications over VoIP networks. To simplify the authentication process, several protocols adopt a verification table to achieve mutual authentication, but the protocols require the SIP server to maintain a large verification table which not only increases energy consumption but also leads to some security issues. Although several attempts have been made to address the intractable problems, designing an energy-efficient authenticated key agreement protocol for SIP-based green VoIP networks is still a challenging task. In this study, we propose an efficient authentication protocol for SIP by using smartcards based on elliptic curve cryptography. With the proposed protocol, the SIP server needs not to store a password or verification table in its database, and so no energy is required for the maintenance of the verification table. Security analysis demonstrates that the proposed protocol can resist various attacks and provides efficient password updating. Furthermore, the experimental results show that the proposed protocol increases efficiency in comparison with other related protocols

A lightweight privacy preserving authenticated key agreement protocol for SIP-based VoIP

Session Initiation Protocol (SIP) is an essential part of most Voice over Internet Protocol (VoIP) architecture. Although SIP provides attractive features, it is exposed to various security threats, and so an efficient and secure authentication scheme is sought to enhance the security of SIP. Several attempts have been made to address the tradeoff problem between security and efficiency, but designing a successful authenticated key agreement protocol for SIP is still a challenging task from the viewpoint of both performance and security, because performance and security as two critical factors affecting SIP applications always seem contradictory. In this study, we employ biometrics to design a lightweight privacy preserving authentication protocol for SIP based on symmetric encryption, achieving a delicate balance between performance and security. In addition, the proposed authentication protocol can fully protect the privacy of biometric characteristics and data identity, which has not been considered in previous work. The completeness of the proposed protocol is demonstrated by Gong, Needham, and Yahalom (GNY) logic. Performance analysis shows that our proposed protocol increases efficiency significantly in comparison with other related protocols

Cryptanalysis and improvement of password-authenticated key agreement for session initiation protocol using smart cards

Session Initiation Protocol (SIP) is one of the most commonly used protocols for handling sessions for Voice over Internet Protocol (VoIP)-based communications, and the security of SIP is becoming increasingly important. Recently, Zhang et al. proposed a password authenticated key agreement protocol for SIP by using smart cards to protect the VoIP communications between users. Their protocol provided some unique features, such as mutual authentication, no password table needed, and password updating freely. In this study, we performed cryptanalysis of Zhang et al.'s protocol and found that their protocol was vulnerable to the impersonation attack although the protocol could withstand several other attacks. A malicious attacker could compute other users’ privacy keys and then impersonated the users to cheat the SIP server. Furthermore, we proposed an improved password authentication key agreement protocol for SIP, which overcame the weakness of Zhang et al.’s protocol and was more suitable for VoIP communications