The use of digital video offers immense opportunities for creators; however, the ability for anyone to make perfect copies and the ease by which those copies can be distributed also facilitate misuse, illegal copying and distribution (“piracy”), plagiarism, and misappropriation. Popular Internet software based on a peer-to-peer architecture has been used to share copyrighted movies, music, software, and other materials. Concerned about the consequences of illegal copying and distribution on a massive scale, content owners are interested in digital rights management (DRM) systems which can protect their rights and preserve the economic value of digital video. A DRM system protects and enforces the rights associated with the use of digital content. Unfortunately, the technical challenges for securing digital content are formidable and previous approaches have not succeeded. We overview the concepts and approaches for video DRM and describe methods for providing security, including the roles of encryption and video watermarking. Current efforts and issues are described in encryption, watermarking, and key management. Lastly, we identify challenges and directions for further investigation in video DRM.

As wireless sensor networks continue to grow, so does the need for effective security mechanisms. Because sensor networks may interact with sensitive data and/or operate in hostile unattended environments, it is imperative that these security concerns be addressed from the beginning of the system design. However, due to inherent resource and computing constraints, security in sensor networks poses different challenges than traditional network/computer security. There is currently enormous research potential in the field of wireless sensor network security. Thus, familiarity with the current research in this field will benefit researchers greatly. With this in mind, we survey the major topics in wireless sensor network security, and present the obstacles and the requirements in the sensor security, classify many of the current attacks, and finally list their corresponding defensive measures. 2

Multicasting is increasingly used as an e#cient communication mechanism for group-oriented applications in the Internet. In order to o#er secrecy for multicast applications, the tra#c encryption key has to be changed whenever a user joins or leaves the system. Such a change has to be communicated to all the current users. The bandwidth used for such rekeying operation could be high when the group size is large. The proposed solutions to cope with this limitation, commonly called 1 a#ects n phenomenon, consist of organizing group members into subgroups that use independent tra#c encryption keys. This kind of solutions introduce a new challenge which is the requirement of decrypting and reencrypting multicast messages whenever they pass from one subgroup to another. This is a serious drawback for applications that require real-time communication such as video-conferencing. In order to avoid the systematic decryption / reencryption of messages, we propose in this paper an adaptive solution which structures group members into clusters according to the application requirements in term of synchronization and the membership change behavior in the secure session. Simulation results show that our solution is e#cient and typically adaptive compared to other schemes.

We develop the foundations for a theory of Group-Centric Secure Information Sharing (g-SIS), characterize a specific family of models in this arena and identify several directions in which this theory can be extended. Traditional approach to information sharing, characterized as Dissemination-Centric, focuses on attaching attributes and policies to an object as it is disseminated from producers to consumers in a system. In contrast, Group-Centric sharing envisions bringing the users and objects together in a group to facilitate sharing. The metaphors “secure meeting room ” and “subscription service ” characterize the Group-Centric approach where participants and information come together to share for some common purpose. Our focus in this paper is on semantics of group operations: Join and Leave for users and Add and Remove for objects, each of which can have several variations called types. We use Linear Temporal Logic to first characterize the core properties of a group in terms of these operations. We then characterize additional properties for specific types of these operations. Finally, we specify the authorization behavior for read access in a single group for a family of g-SIS models and show that these models satisfy the above-mentioned properties using the NuSMV model checker. Categories and Subject Descriptors

In group communication, users often have different access rights to multiple data streams. Based on the access relation of users and data streams, users can form partially ordered relations, and data streams can form partially ordered relations. In this paper, we propose a key management scheme for hierarchical access control, which considers both partially ordered user relations and partially ordered data stream relations. We also propose an algorithm for constructing a logical key graph, which is suitable even when users and data streams have complex relations. Simulation results show that our scheme can significantly improve the efficiency of key management.

Secure Information Sharing (SIS) or “share but protect ” is a challenging and elusive problem both because of its broad scope and complexity ranging right from conception (objective and policy) to culmination (implementation). In this paper, we consider how to solve SIS challenges with three main and conflicting objectives: scalability, usability and high-assurance. In the context of SIS, high-assurance requires strong controls on the client. It is widely accepted that such controls cannot be entirely software-based. In this regard, we consider solutions based on commercially emerging hardware-rooted Trusted Computing Technology. For SIS, we argue super-distribution (“protect once and access wherever authorized”) and off-line access are necessary to achieve scalability and usability. We limit super-distribution to occur within a group of Trusted Platform Module [1] or TPM-enabled machine. For simplicity, we assume all content that are distributed to be read-only. Drilling down,

Abstract—We design a Tree-based Forward Digest Protocol (TFDP) to verify data integrity in distributed media streaming for content distribution. Several challenges arise, including the timing constraint of streaming sessions, the involvement of multiple senders, and the untrustworthiness of these senders. A comprehensive comparison is presented on the performance of existing protocols and TFDP, with respect to communication and computation overhead. Both simulation and Internet-based experimental results are presented to demonstrate the effectiveness of TFDP. Index Terms—Data integrity, message digest, and media streaming. 1

Publish/subscribe systems provide an efficient, event-based, wide-area distributed communications infrastructure. Large scale publish/subscribe systems are likely to employ components of the event transport network owned by cooperating, but independent organisations. As the number of participants in the network increases, security becomes an increasing concern. This paper extends previous work to present and evaluate a secure multi-domain publish/subscribe infrastructure that supports and enforces fine-grained access control over the individual attributes of event types. Key refresh allows us to ensure forward and backward security when event brokers join and leave the network. We demonstrate that the time and space overheads can be minimised by careful consideration of encryption techniques, and by the use of caching to decrease unnecessary decryptions. We show that our approach has a smaller overall communication overhead than existing approaches for achieving the same degree of control over security in publish/subscribe networks.

In this paper we overview a large number of currently known group key ex-change protocols while focusing on the protocols designed for more than three par-ticipants (for an overview of two- and three-party key exchange protocols we refer to [BM03, DB05c]). For each mentioned protocol we briefly describe the current state of security based on the original analysis as well as later results appeared in the liter-ature. We distinguish between (i) protocols with heuristic security arguments based on informally defined security requirements and (ii) protocols that have been proven secure in one of the existing security models for group key exchange. Note, this paper continues the work started in [Man06] which provides an analytical survey on security requirements and currently known models for group key exchange. We emphasize that the following survey focuses on the security aspects of the protocols and does not aim to provide any efficiency comparison. The reader interested in this kind of surveys we

We present a new encryption mode of operation that allows nodes of a network to exchange messages securely (i.e. encrypted and authenticated) without sharing a common key or using public key cryptography. Our scheme is well adapted to networks, such as ad hoc, overlay or sensor networks, where nodes have limited capabilities and can share only a small number of symmetric keys. It provides privacy and integrity protection. We show that our proposal can be used in wireless sensor networks to send encrypted packets to very dynamic sets of nodes without having to establish and maintain group keys. These sets of nodes can be explicitly specified by the source or can be specified by the network according to some criteria, such as their location, proximity to an object, temperature range. As a result, a node can, for example, send encrypted data to all the nodes within a given geographical area, without having to identify the destination nodes in advance. Finally we show that our proposal can be used to implement a secure and scalable aggregation scheme for wireless sensor networks 1. I.