Have I Met You Before? Using Cross-Media Relations to Reduce SPIT

Most legitimate calls are from persons or organizations with strong social ties such as friends. Some legitimate calls, however, are from those with weak social ties such as a restaurant the callee booked a table on-line. Since a callee's contact list usually contains only the addresses of persons or organizations with strong social ties, filtering out unsolicited calls using the contact list is prone to false positives. To reduce these false positives, we first analyzed call logs and identified that legitimate calls are initiated from persons or organizations with weak social ties through transactions over the web or email exchanges. This paper proposes two approaches to label incoming calls by using cross-media relations to previous contact mechanisms which initiate the calls. One approach is that potential callers offer the callee their contact addresses which might be used in future correspondence. Another is that a callee provides potential callers with weakly-secret information that the callers should use in future correspondence in order to identify them as someone the callee has contacted before through other means. Depending on previous contact mechanisms, the callers use either customized contact addresses or message identifiers. The latter approach enables a callee to label incoming calls even without caller identifiers. Reducing false positives during filtering using our proposed approaches will contribute to the reduction in SPIT (SPam over Internet Telephony)

Handover and Load Balancing in Universal Mobile Telecommunications System Network Using Software Defined Network

This article presents an evaluation of the handover (HO) and Load balancing under the Universal Mobile Telecommunication System (UMTS) with the addition of a Software Defined Networks (SDN). This work is based on UMTS mobility, which is adopted by the S1 interface, with a level 3 Mobile IPv6 (MIPv6) in addition the new program with C ++, by the use of Session Initiation Protocol (SIP) between two end users to evaluate the performances of UMTS networks with the SDN paradigm.SDN is a program running on one or more nodes of the network. It will calculate the routes to be taken by incoming packets in the network and will then communicate them to all virtual switches. The SDN controller has a central role for the proper functioning of the network. Its decisions have a direct impact on users' perceived performance. It is therefore crucial that its decisions are taken at best

Secure Communication Using Electronic Identity Cards for Voice over IP Communication, Home Energy Management, and eMobility

Using communication services is a common part of everyday life in a personal or business context. Communication services include Internet services like voice services, chat service, and web 2.0 technologies (wikis, blogs, etc), but other usage areas like home energy management and eMobility are will be increasingly tackled. Such communication services typically authenticate participants. For this identities of some kind are used to identify the communication peer to the user of a service or to the service itself. Calling line identification used in the Session Initiation Protocol (SIP) used for Voice over IP (VoIP) is just one example. Authentication and identification of eCar users for accounting during charging of the eCar is another example. Also, further mechanisms rely on identities, e.g., whitelists defining allowed communication peers. Trusted identities prevent identity spoofing, hence are a basic building block for the protection of communication. However, providing trusted identities in a practical way is still a difficult problem and too often application specific identities are used, making identity handling a hassle. Nowadays, many countries introduced electronic identity cards, e.g., the German "Elektronischer Personalausweis" (ePA). As many German citizens will possess an ePA soon, it can be used as security token to provide trusted identities. Especially new usage areas (like eMobility) should from the start be based on the ubiquitous availability of trusted identities. This paper describes how identity cards can be integrated within three domains: home energy management, vehicle-2-grid communication, and SIP-based voice over IP telephony. In all three domains, identity cards are used to reliably identify users and authenticate participants. As an example for an electronic identity card, this paper focuses on the German ePA

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

Analysis of Token and Ticket Based Mechanisms for Current VoIP Security Issues and Enhancement Proposal

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Automated Runtime Risk Management for Voice over IP Networks and Services

International audienceVoice over IP (VoIP) has become a major paradigm for providing telephony services at a lower cost and with a higher flexibility. VoIP infrastructures are however exposed to multiple security issues both inherited from the IP layer and specific to the application layer. In the meantime, protection mechanisms are available but may seriously impact on the continuity and quality of such critical services. We propose in this paper an automated risk management schema for continuously adapting VoIP equipment exposure by activating security safeguards in a dynamic and progressive manner. We describe the architecture supporting our solution, the considered risk model taking into account VoIP properties and the algorithms for restricting and relaxing the risk level of the VoIP service at runtime. The benefits and limits of our solution are evaluated through an implementation prototype and an extensive set of experimental results in the case scenario of SPIT attacks

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