Multimedia security in group communications: recent progress in key management,authentication, and watermarking

Multicast is an internetwork service that provides efficient delivery of data from a source to multiple receivers. It reduces the bandwidth requirements of the network and the computational overhead of the host devices. This makes multicast an ideal technology for communication among a large group of participants. Secure group communications involves many service types include teleconferencing, pay TV and real-time delivery of stock quotes. IP multicast is the traditional mechanism to support multicast communications. Multicast security includes group membership control, secure key distribution, secure data transfer and copyright protection. This paper is an overview of the schemes proposed for group key management, authentication and watermarking in wired networks with fixed members and wireless networks with mobile members.A preliminary version of this paper was presented at the IASTED International Conference on Communications and Computer Networks, Cambridge, MA 4-6 November 2002.     

Adaptive per-user per-object cache consistency management for mobile data access in wireless mesh networks

We propose and analyze an adaptive per-user per-object cache consistency management (APPCCM) scheme for mobile data access in wireless mesh networks. APPCCM supports strong data consistency semantics through integrated cache consistency and mobility management. The objective of APPCCM is to minimize the overall network cost incurred due to data query/update processing, cache consistency management, and mobility management. In APPCCM, data objects can be adaptively cached at the mesh clients directly or at mesh routers dynamically selected by APPCCM. APPCCM is adaptive, per-user and per-object as the decision regarding where to cache a data object accessed by a mesh client is made dynamically, depending on the mesh client’s mobility and data query/update characteristics, and the network’s conditions. We develop analytical models for evaluating the performance of APPCCM and devise a computational procedure for dynamically calculating the overall network cost incurred. We demonstrate via both model-based analysis and simulation validation that APPCCM outperforms non-adaptive cache consistency management schemes that always cache data objects at the mesh client, or at the mesh client’s current serving mesh router for mobile data access in wireless mesh networks.     

一种基于LKH的分层式安全组播密钥管理方案

安全组播是组播技术走向实用化必须解决的问题。在组成员动态变化时,设计一个高效的密钥管理方案是安全组播研究的主要问题。该文提出了一种基于LKH模型的分层式组播密钥管理方案。该方案基于分层机制将一个组播分为几个小组,并且采用了指数函数和随机密钥,使得在组成员离开组播时,具体的密钥更新由组成员自己完成。该方案比传统方案减少了密钥更新开销量,提高密钥更新效率,并缩减了密钥存储量。     

Distributed dynamic mobile multicast

Traditional mobile multicast schemes have either high multicast tree reconfiguration cost or high packet delivery cost. The former affects service disruption time while the latter affects packet delivery delay. Although existing region-based mobile multicast schemes offer a trade-off between two costs to some extent, most of them do not determine the size of the service range, which is critical to network performance. In this paper, we propose a novel approach, called Distributed Dynamic Mobile Multicast (D²M²), to dynamically determine the optimal service range according to the mobility and service characteristics of a user. We derive an analytical model to formulate the costs of multicast tree reconfiguration and multicast packet delivery. The model is based on a Markov chain that analyzes a mobile node’s movement in a 2D mesh network. As the complexity of computing steady probability is high, we aggregate the Markov states by leveraging mobility symmetry. Simulation shows that the network performance is enhanced through D²M².     

Review of multicast routing mechanisms in mobile ad hoc networks

Frequent interactions among the group members of distributed wireless network environment may be facilitated with the help of Mobile Ad Hoc NETworks (MANETs). Some of the group-oriented applications include disaster management, battlefields, audio/video conferencing, e-commerce, e-education, etc. Group communication demands dynamic construction of efficient and reliable multicast routes under user mobility and varying channel conditions. Multicast routing mechanisms in MANETs have been consistently improved by researchers considering various performance measures such as energy efficient route establishment, packet delivery ratio, quicker and faster proactive route recovery, network life time, reliability, Quality of Service (QoS) based on bandwidth, delays, jitters, and security. The paper focuses on most recent reliable and QoS based multicast routing mechanisms that helps in multimedia communication over MANETs. The mechanisms are considered under different topological routing categories such as mesh, tree, zone and hybrid. We provide an overview of existing multicast routing mechanisms based on routing categories and point to directions for future research and development.     

Performance analysis of hierarchical group key management integrated with adaptive intrusion detection in mobile ad hoc networks

We develop a mathematical model to quantitatively analyze a scalable region-based hierarchical group key management protocol integrated with intrusion detection to deal with both outsider and insider security attacks for group communication systems (GCSs) in mobile ad hoc networks (MANETs). Our proposed adaptive intrusion detection technique is based on majority voting by nodes in a geographical region to cope with collusion of compromised nodes, with each node preloaded with anomaly-based or misuse-based intrusion detection techniques to diagnose compromised nodes in the same region. When given a set of parameter values characterizing operational and environmental conditions, we identify the optimal intrusion detection rate and the optimal regional area size under which the mean time to security failure of the system is maximized and/or the total communication cost is minimized for GCSs in MANET environments. The tradeoff analysis in performance versus security is useful in identifying and dynamically applying optimal settings to maximize the system lifetime for scalable mobile group applications while satisfying application-specific performance requirements.     

Admissible bilinear map-based key management protocol for HPCCS in heterogeneous network

The high-speed transfer rate and various services of the wired network have been combined with the convenience and mobility of wireless networks. This era of combined wire/wireless is being disseminated by new technology that creates new service applications and brings changes to both users and service providers. Network integration is a very important in this wire/wireless service, it is integrated by the convergence between heterogeneous networks and the integration of transmission technologies across networks. In this situation, existing security and communication technologies are difficult to apply due to the need to integrate with heterogeneous networks. Network security has many vulnerabilities. In existing homogeneous networks, user authentication and key management between heterogeneous networks are needed to be adapted to new technology. The establishment of security technologies to heterogeneous devices is also crucial between homogeneous networks. In this paper, we propose secure, efficient key management in a heterogeneous network environment. Therefore, it provides secure communication between heterogeneous network devices.     

基于混合应答机制的层次型可靠移动组播算法

由于移动主机位置的不断改变引起组播树的频繁重构,已有的可靠组播算法已不适用于主机移动的无线网络环境.首先提出了前向网络签署的移动组播机制,然后在基于区域的层次型网络结构中,集成前向网络签署和远程签署,采用ACK和NAK相结合的应答机制,在子网局部范围内使用组播恢复机制和应答抑制机制,提出了一个新的支持主机移动的可靠移动组播算法.在重传延迟、重传开销、协议开销和服务中断时间这些方面的模拟结果和分析显示,该算法是一个高效的、可扩展的可靠移动组播算法.     

Efficient Multicast Algorithms for Multichannel Wireless Mesh Networks

The wireless mesh network is an emerging technology that provides high quality service to end users as the "last mile” of the Internet. Furthermore, multicast communication is a key technology for wireless mesh networks. Multicast provides efficient data distribution among a group of nodes. However, unlike other wireless networks, such as sensor networks and MANETs, where multicast algorithms are designed to be energy efficient and to achieve optimal route discovery among mobile nodes, wireless mesh networks need to maximize throughput. This paper proposes two multicast algorithms: the Level Channel Assignment (LCA) algorithm and the Multichannel Multicast (MCM) to improve the throughput for multichannel and multi-interface mesh networks. The algorithms build efficient multicast trees by minimizing the number of relay nodes and total hop count distances of the trees. The algorithms use dedicated channel assignment strategies to reduce the interference to improve the network capacity. We also demonstrate that using partially overlapping channels can further diminish the interference. Furthermore, additional interfaces help to increase the bandwidth, and multiple gateways can further shorten the total hop count distance. Simulations show that those algorithms greatly outperform the single-channel multicast algorithm. We also observe that MCM achieves better throughput and shorter delay while LCA can be realized in distributed manner.     

基于Steiner树的层次型无线传感器网络安全组播协议

在基于查询的无线传感器网络中,组播技术的应用可大幅减少传感器节点的能量消耗,延长节点寿命.针对大型无线传感器网络组播协议性能不高,且易遭受攻击等问题,提出了基于Steiner树的层次型无线传感器网络安全组播协议.该协议主要运用Steiner树与分簇网络的思想,将Steiner树的高效性与簇的高扩展性相结合,提高了无线传...     

一种安全组播服务体系结构

组播可以有效地实现多节点之间的通信，目前组播应用在互联网上已经越来越广泛．安全是阻碍组播应用进一步发展的重要问题．在以往的安全组播方案中，组播安全管理都由组播发起者来承担．本文提出了可代替组播发起者来承担组播安全管理的安全组播服务体系结构SMSA（Secure Multicast Service Arehitecture），SMSA可以同时为大量组播组提供安全服务,本文介绍了SMSA的详细实现方案及实验过程，结果表明SMSA提高了组播安全的效率并具有良好的可扩展性．     

Hydra: Efficient multicast routing in MANETs using sender-initiated multicast meshes

We present Hydra, the first multicast routing protocol for MANETs that establishes a multicast routing structure approximating the set of source-rooted shortest-path trees from multicast sources to receivers, without requiring the dissemination of control packets from each source of a multicast group. Hydra accomplishes this by dynamically electing a core for the mesh of a multicast group among the sources of the group, and aggregating multicast routing state in the nodes participating in multicast meshes, so that only control packets from the core are disseminated towards the receivers of a group. We prove that Hydra establishes correct routes from senders to receivers of a multicast group when multicast state information is aggregated. We also present simulation results illustrating that Hydra attains comparable or higher delivery ratios than the On-Demand Multicast Routing Protocol (ODMRP), but with considerably lower end-to-end delays and far less communication overhead. Results are shown for scenarios using 802.11 DCF and TDMA as the MAC layer protocols and using random waypoint and group mobility as mobility models.     

Scalable network-on-chip architecture for configurable neural networks

Providing highly flexible connectivity is a major architectural challenge for hardware implementation of reconfigurable neural networks. We perform an analytical evaluation and comparison of different configurable interconnect architectures (mesh NoC, tree, shared bus and point-to-point) emulating variants of two neural network topologies (having full and random configurable connectivity). We derive analytical expressions and asymptotic limits for performance (in terms of bandwidth) and cost (in terms of area and power) of the interconnect architectures considering three communication methods (unicast, multicast and broadcast). It is shown that multicast mesh NoC provides the highest performance/cost ratio and consequently it is the most suitable interconnect architecture for configurable neural network implementation. Routing table size requirements and their impact on scalability were analyzed. Modular hierarchical architecture based on multicast mesh NoC is proposed to allow large scale neural networks emulation. Simulation results successfully validate the analytical models and the asymptotic behavior of the network as a function of its size.     

一种动态组播的密钥更新算法

为了保证组播通信的机密性,安全组播使用不为组外成员所知的密钥来加密数据,并随组成员关系的变化而动态更新。基于树型分层式密钥管理方式使用户变更时的密钥更新代价减小,但前提是密钥树必须保持平衡。本文提出了一种应用m序B树作为组密钥树的密钥管理方法,在组播组中加入一个新成员,本方案比传统方案减少了密钥更新开销量,提高密钥更新效率。     

安全组播中的密钥树最优结构

组播常用来对一组用户发送数据．为了保障安全性，安全组播使用组内共享的加密密钥对组内通信进行加密．因为组成员关系的动态性，有效进行组密钥管理成为安全组播通信性能的关键．本文研究了组密钥管理的密钥树结构，并提出了一种新的基于组成员更新概率的最优密钥树结构．这种结构能够进一步减少系统开销．实验结果表明这种密钥树结构要优于其它基于组成员更新概率的密钥树结构，同时理论分析给出了这种结构的平均更新代价的取值范围．     

A novel group key agreement protocol for wireless mesh network

Group key agreement is the core of secure group communication. In wireless networks, the privacy problem becomes more crucial and urgent for mobile users due to the open nature of radio media. In this paper, we proposed a novel group key agreement protocol based on trusted third Party, applied in collaboration between mobile users for wireless Mesh network. The security verification (PCL logic) and performance analysis show that, our protocol not only provides privacy protection for group members, but also authenticates all participants by adopting certificates. More important, in the proposed protocol, the computation cost and traffics for each group member are largely reduced to improve the implementation efficiency of the protocol. Therefore, our protocol is a novel, reliable group key agreement protocol, and it is well suited for wireless mesh network.     

一种无线传感器网络的密钥管理方案

目前很多无线传感器网络的应用是建立在群组式通讯的模式之上,如何建立一个用以加密群组通讯的组密钥,来防范攻击者窃听无线传感器网络上的通讯,近年来引起广泛关注。为了在有限资源的无线传感器网络能安全进行群组通讯,本文只使用对称加密算法和单向哈希函数提出了一种具有有效性和扩充性的组密钥管理方案,并可满足前向和后向安全性。与目前现有的群组密钥相比,方案不仅具有较好的效率,并且更适合于无线传感器网络。     

一种基于Mobicast 的最优QoS 安全认证算法

为保证无线传感器追踪网络(WSTNs)移动组播服务质量(QoS)和安全性,在Mobicast协议基础上提出一种最优QoS安全认证算法,将被监测实体运动速度与组播应用服务需求相关参数向量化,并在其基础上得出满足最优QoS的多级μTESLA认证协议级数M的函数表达式.分析和仿真结果表明,该算法能够对达到特定QoS需求所需的相应安全认证密钥级数进行有效分析和预测,且对于网络能耗和通信实时性的影响是可以接受的.     

一种新的无线网络组播密钥管理方案

在无线网络中,多播组成员的变化是劝态的,在某些特殊应用中,成员可能会在一段时间段内频繁地加入和离开,此时有线网络中的传统组播密钥管理方法就会体现出不足。针对此不足,提出一种适应于无线网络的组播密钥管理方案。该方案根据地理位置将组播成员划分为不同子组,每个子组根据本子组成员的变化情况来设置密钥更新间隔TTR和请求数的阀值RT。通过子组管理员来协调本子组与其他成员通信保持一致,提高通信效率、降低异步问题。理论分析和仿真结果表明：该方案在保证组播成员安全通信的基础上,显著地降低无线网络中的组播应用因密钥更新导致的通信开销,从而提高密钥更新效率,使无线网络在处理大流量等应用问题的同时,也具有较高的安全性。