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Srinivas, PreethiPrivate Key Allocation based Access Control Scheme for Social Networks
Master of Computer Science, Miami University, 2010, Computer Science and Systems Analysis
The problem of sharing resources in a secure manner in a social network has been addressed by various publications. Some of these schemes depend on a centralized server as a trusted third party, all of them require both the users (the user providing access and the user accessing the resource) to be online in order for the resource to be shared. This requirement is a drawback in real world as it is not feasible for all the users to come online each time their resource is accessed. We have designed and implemented a social network access control mechanism where the different users can have asynchronous access to their friends‟ information (based on access rule satisfaction) and hide information from the server. The access control model in our system allows users to specify access policies based on distance in the social network. This access control model has been enforced via a key management system.

Committee:

Keith Frikken, PhD (Advisor); William Brinkman, PhD (Committee Member); Lukasz Opyrchal, PhD (Committee Member)

Subjects:

Computer Science; Social Structure; Technology

Keywords:

social network; access control; key management; resource sharing; security

CHENG, YISecurity Mechanisms for Mobile Ad Hoc and Wireless Sensor Networks
PhD, University of Cincinnati, 2008, Engineering : Computer Science and Engineering

Wireless Ad Hoc Networks have emerged as an advanced networking paradigm based on collaborative efforts among multiple self-organized wireless communication devices. Without the requirement of a fixed infrastructure support, wireless ad hoc networks can be quickly deployed anywhere at any time when needed. The decentralized nature, minimal configuration and quick deployment of wireless ad hoc networks make them suitable for various applications, from disaster rescue, target tracking to military conflicts. Wireless ad hoc networks can be further categorized into mobile ad hoc networks (MANETs), wireless sensor networks (WSNs), and wireless mesh networks (WMNs) depending on their applications.

Security is a big challenge in wireless ad hoc networks due to the lack of any infrastructure support, dynamic network topology, shared radio medium, and resource-constrained wireless users. Most existing security mechanisms applied for the Internet or traditional wireless networks are neither applicable nor suitable for wireless ad hoc network environments. In MANETs, routing security is an extremely important issue, as the majority of the standard routing protocols assume non-hostile environments. Once deployed in a hostile environment and working in an unattended mode, existing routing protocols are vulnerable to various attacks. To address these concerns, we propose an anonymous secure routing protocol for MANETs in this dissertation, which can be incorporated with existing routing protocols and achieve enhanced routing security with minimum additional overheads.

In WSNs, key distribution and management is the core issue of any security approaches. Due to extremely resource-constrained sensor nodes and lack of any infrastructure support, traditional public-key based key distribution and management mechanisms are commonly considered as too expensive to be employed in WSNs. In this dissertation, we propose two efficient pairwise key pre-distribution and management mechanisms for both distributed and hierarchical large-scale WSNs, which enable establishing secure links between any two sensor nodes located within their communication range. As we know, sensing and communication are two fundamental characteristics of WSNs, and they cannot be addressed separately. Existing work on sensing coverage mainly focus on how to use the minimum number of sensors to achieve a required coverage, while security constraints are not sufficiently addressed. We propose an effective key distribution approach for randomly deployed WSNs, based on random graph theory and a realistic random key pre-distribution mechanism, in order to achieve both robust sensing coverage and secure connectivity simultaneously in a hostile deployment environment.

Committee:

Dharma Agrawal (Committee Chair); Jerome Paul (Committee Member); Wen-Ben Jone (Committee Member); Chia-Yung Han (Committee Member); Ernest Hall (Committee Member)

Subjects:

Communication; Computer Science

Keywords:

Wireless Ad Hoc Network; Mobile Ad Hoc Network (MANET); Wireless Sensor Network (WSN); Routing; Security; Cryptography; Key Management; Distributed Wireless Network; Hierarchical Wireless Network; Sensing Coverage; Secured Connectivity

KAMAT, SIDDESH DEVIDASHANDLING SOURCE MOVEMENT OVER MOBILE-IP AND REDUCING THE CONTROL OVERHEAD FOR A SECURE, SCALABLE MULTICAST FRAMEWORK
MS, University of Cincinnati, 2003, Engineering : Computer Science
Multicasting is a mechanism of efficient delivery of packets from a source(s), intended for a group of hosts. The packets are transmitted using a ‘group address’ in the destination address field, and all subscribed hosts receive the packets. Multicasting reduces the redundancy that would result in case every source decides to transmit packets individually for every other host waiting for the transmission. A multicast tree is constructed which takes care of transmission of the packets for all the recipients. However, problems such as source movement, construction of an efficient multicast tree, a reliable and secure delivery of packets, etc. need to be taken care of. Several recent proposals have focused on handling recipient mobility, but not much attention has been given to the problem of source movement, which may affect the complete multicast delivery tree. In this thesis, we have proposed a scheme to handle the movement of a multicast source. The proposed approach has shown to reduce the network overload as compared to the other existing approaches. We have also addressed the issue of providing a scalable framework for achieving secure multicast transmissions. Secure transmissions are necessary for certain applications where non-authenticated hosts are precluded from sending and receiving packets for the group. The issue of efficient and scalable key management is of prime concern, since multicast generally involves a large number of hosts. A change in group membership often affects many hosts. IOLUS is one existing framework to provide secure multicast, with a central controller and associated trusted entities handling the hosts. However, it encumbers a large overhead whenever members leave the group, when it needs to propagate the new key to the other members in the group. We propose a better, scalable solution, the M-IOLUS framework, which introduces the novel concept of dynamically forming micro-groups. We have performed extensive simulations for both wired and wireless environments, which show a considerable reduction in the overhead incurred, as compared to IOLUS.

Committee:

Dr. Dharma Agrawal (Advisor)

Subjects:

Computer Science

Keywords:

multicast; source movement; IOLUS; security; key management

GUPTA, MEETUMINIMIZATION OF REKEYING OVERHEAD FOR A SECURE AND SCALABLE MULTICAST FRAMEWORK
MS, University of Cincinnati, 2004, Engineering : Computer Science
Multicast is an internetworking service that provides efficient delivery of data from a sender to multiple recipients. Security is an important issue in multicasting and is increasingly becoming a bottleneck. Security features like confidentiality, authenticity, and integrity can be provided with the help of cryptographic techniques like encryption. Access control to multicast services poses a huge problem and is an important issue to be addressed. A secret group key is used to prevent unauthorized access which has to be changed frequently in a dynamic membership environment. This results in a significant increase in the control overhead during the group key management process. In this research, we reduce this overhead by using polynomial computations to distribute the group key. One of the existing frameworks, IOLUS, incurs a large overhead when a group member leaves the group. We propose a scalable approach in which this overhead is drastically reduced.

Committee:

Dr. Dharma Agrawal (Advisor)

Subjects:

Computer Science

Keywords:

Security; Key Management; Multicast; Mobility; IOLUS

POOSARLA, RAJANI DEVIAUTHENTICATED ROUTE FORMATION AND EFFICIENT KEY MANAGEMENT SCHEMES FOR SECURING Ad Hoc NETWORKS
MS, University of Cincinnati, 2003, Engineering : Computer Science
Ad hoc networks provide a new approach for wireless communication. These networks have no pre-deployed infrastructure available for achieving end-to-end routing of packets in the network. Nodes communicate with each other without the intervention of centralized access points or base stations, so each node acts both as a router and as a host. Securing routing in ad hoc networks creates difficulties not present in traditional network: neither centrally administrated secure routers nor strict policy exists in an ad hoc network; the nodes in the networks can be highly mobile, thus rapidly changing the network topology and the presence or absence of links. So the routing in ad hoc networks is especially hard to accomplish securely, robustly and efficiently. Security primitives such as authentication, non-repudiation, data integrity and confidentiality, which would otherwise be provided by a central server, must be enabled by one or more network nodes. In this thesis, we focus on two issues of security, routing security and key management. We have discussed various threats to routing protocols in ad hoc networks and proposed methods to enhance the security of these protocols. We have put forth a new authentication scheme for on-demand routing protocols, specifically Dynamic Source Routing (DSR), by using public key cryptography in order to prevent the attacks against routing. The use of public key infrastructure in ad hoc networks raises the issue of key management. Certification of public keys of the nodes belonging to an ad hoc network is a non-trivial problem. Existing techniques for certifying keys are not well suited for ad hoc networks due to their sensitivity to single point of failure. We have defined a new key management paradigm, which can effectively deal with the challenges inherent in ad hoc networks and combat the attacks on the key management system itself. The proposed solution is then integrated into an existing hierarchical routing protocol.

Committee:

Dr. Dharma Agrawal (Advisor)

Subjects:

Computer Science

Keywords:

Ad Hoc networks; security; authentication; key management

SHAH, VIVEKPARALLEL CLUSTER FORMATION FOR SECURED COMMUNICATION IN WIRELESS AD HOC NETWORKS
MS, University of Cincinnati, 2004, Engineering : Computer Science
Routing protocols in wireless ad hoc network are highly insecure and prone to various attacks owing to its inherent characteristics of open medium, dynamically changing topologies and distributed cooperation between the member nodes. Having a secure routing protocol in wireless ad hoc networks appears to be a problem that is not trivial to solve. We propose a scheme to enhance the fault-tolerance of cluster head’s functionality in CBRP. CBRP with a single cluster head is single point of failure and unsuitable especially for functionalities like key distribution. By distributing the cluster head service to a group of cluster heads called Council nodes and utilizing the (k, n) secret sharing scheme, we can increase the fault tolerance of network manifolds against security attacks. Simulation results obtained demonstrates that our proposed algorithm enables simultaneous formation the Council based clusters, thereby making the scheme time efficient and comparable to CBRP. Results also show that since large size clusters are formed in Council based clusters, it is feasible to apply (k, n) secret sharing concepts. The scheme is more suitable for low mobility networks due to the less signaling overhead involved in during cluster reformations.

Committee:

Dr. Dharma Agrawal (Advisor)

Subjects:

Computer Science

Keywords:

Ad Hoc Networks; Network Security; Key Distribution; Key Management; Wireless Communications