Abstract : In this article we present a system for sharing a Conditional Access Module among different visualization devices. Current pay-TV systems require having conditional access modules and smart cards replicated at every visualization device willing to access Pay-TV contents. In this article, we show how a home gateway, capable of securely distribute decryption keys to home visualization device, an inexpensive descrambler, and a home network, enable a flexible solution to access Pay-TV.

Abstract : SCTP handover is too slow to be useful as a mobility solution for most applications. With quicker handovers, SCTP will be an interesting solution to mobility. SCTP uses retransmissions as probes for path failure detection. Congestion control forces slow paced retransmissions but quick failovers need fast paced probes. Our solution is to stop using retransmissions as probes. Instead, we propose active path monitoring using unreliable heartbeats. Applications can tune this algorithm to meet their own requirements. We show data from a simple experiment in a real environment.

Abstract : In this paper we present a system to enable pay-per- view services in mobile handhelds which takes benefits of both DVB-H and UMTS networks. DVB-H infrastructure provides a more appropriate content delivery framework that UMTS. Despite this fact, UMTS can play an important role for charging and key distribution for pay-per-view applications by means of the provider SIM smart card.

Abstract : Abstract Mobile devices of new generation are able to connect to multiple networks and to constitute new infrastructureless networks. These dynamic environments require new security paradigms and automatic mechanisms to minimize user intervention. Our goal is the definition of a new concept of distance that considers the current domain constraints and the user preferences. This paper addresses some of the problems of these complex environments by using Multidimensional Scaling (MDS) techniques. We also propose collaborative mechanisms for automatic environment marking. Based on these ideas we have developed Pervasive Interaction Manager (PervsIM), a decision mechanism that selects the most appropriate network or peer to interact with. Besides we have defined an embedded access control module which ensures that PervsIM decisions are followed by all applications. Furthermore, several simulation results and implementation details outline how these results can be incorporated in today’s mobile devices.

Abstract : Non-repudiation protocols are of great importance for electronic interactions. Different protocols have been proposed in this field, progressively relaxing the requirements on the computing power of both parties, and on the load and involvement of a trusted third party (TTP). Besides, there is a need to provide mobile users with a protocol adequate for ad hoc scenarios, where only unreliable channels can be guaranteed, and where the CA may not be reachable. In this paper we propose a new version of the fair non-repudiation protocol proposed by Gürgens et al. in [Sigrid Gürgens, Carsten Rudolph, Holger Vogt, On the security of fair non-repudiation protocols, in: Colin Boyd, Wenbo Mao (Eds.), ISC, Lecture Notes in Computer Science, vol. 2851, Springer, 2003, pp. 193-207]. We show unfair scenarios that can appear if one party controls the communication among the TTP and the other party. We introduce notary agents, which play the TTP role, and run our fair non-repudiation protocol. Notary agents execute inside the smart card, and sign the protocol messages with the user’s private key on his behalf. Our approach enables the protocol to run on unreliable channels, disconnected from the CA.

Abstract : Smart Cards are becoming a ubiquitous means for securing a wide range of interactive applications. However in many cases its use is limited for authentication purposes only. In this paper we extend the use of smart cards for carrying abstract user interface descriptions which can be rendered on different and potentially remote clients that in addition can support different interaction modalities. This adds on the one hand to the security since a backend application cannot be used without the UI description, and on the other hand to the versatility of applications, since all devices with a respective renderer for certain modalities can be utilized.