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Persea: A Sybil-Resistant Social DHT  


P2P systems are inherently vulnerable to Sybil attacks, in which an attacker creates a large number of identities and uses them to control a substantial fraction of the system. We propose Persea, a novel social network-based P2P system that derives its Sybil resistance by assigning IDs through a bootstrap tree, the graph of how nodes have joined the system through invitations. Unlike prior Sybil-resistant P2P systems based on social networks, Persea does not rely on the assumptions that have been shown to be unreliable in real social networks. In addition, Persea uses a replication mechanism in which each (key, value) pair is stored in nodes that are evenly spaced over the network. Thus, even if attackers occupy a given region, the desired (key, value) pair can be retrieved from other regions in the network. We evaluate Persea in analysis and in simulations with social network datasets and show that it provides better lookup success rates than prior work with modest overheads. We have also designed and evaluated an improved version of Persea, called iPersea.

ReDS: A Framework for Reputation-Enhanced DHTs  

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Distributed hash tables (DHTs), such as Chord and Kademlia, offer an efficient means to locate resources in peer-to-peer (P2P) networks. Unfortunately, malicious nodes on a lookup path can easily subvert such queries. Several systems, including Halo (based on Chord) and Kad (based on Kademlia), mitigate such attacks by using redundant lookup queries. Much greater assurance can be provided; we design Reputation for Directory Services (ReDS), a reputation-based framework for improving the resilience of searches against malicious nodes in deterministic and nondeterministic DHTs. Through extensive simulations, we demonstrate that ReDS significantly improves lookup success rates for Halo and Kad over a wide range of conditions, even against strategic attackers. 

SDA-2H: Understanding the Value of Background Cover Against Statistical Disclosure   


The statistical disclosure attack (SDA) is an effective method for compromising the anonymity of users in a mix-based system.  In this project, we develop SDA-2H, an extension to SDA. We specifically use SDA-2H as a tool to measure the previously unknown effects of background cover on the anonymity of mix-based systems. Our study quantifies the importance of background cover traffic, which we show in simulation to be effective in various scenarios. Using the information gleaned from these experiments, coupled together with a greater understanding of mixes, we can be one step closer to obtaining the ideal form of anonymous communication, one that is insusceptible to any attack.



Time and Space Efficient Algorithm for Consumer's Priority Product Management                                                                                                    

In this competitive free-market economy, consumers' priority product management is a candidate for high degree of attention. We leverage the concept of balanced binary search tree to design an efficient algorithm for consumers' priority product management. Our algorithm is simulated for one million test cases, where it shows satisfactory performance in terms of time and space complexity. 

Making Findbugs more Powerful                                                                                                                                                                       ​

Findbugs is a widely used bug-finding tool, which supports plug-in architecture in Java platform for adding new bug detectors. In this project, we design bug detectors to detect different bug patterns that could not be detected by the existing Findbugs tool. The effectiveness of our new bug detectors is tested with a number of popular applications.

The Mechanisms to Ensure Maximum Connectivity and Data Transmission in Wireless Sensor Networks                                         

In this project, we design a novel topology discovery algorithm for efficient data dissemination and aggregation in sensor networks, with an efficacious fault tolerance mechanism ensuring maximum connectivity among operational nodes at the failure of a node. 


Mahdi Nasrullah Al-Ameen and Matthew Wright. iPersea: Towards improving the Sybil-resilience of social DHT. In Journal of Network and Computer Applications. Vol. 71, pp. 1-10. August 2016.

Ruj Akavipat, Mahdi N. Al-Ameen, Apu Kapadia, Zahid Rahman, Roman Schlegel, and Matthew Wright. ReDS: A Framework for Reputation-Enhanced DHTs. In IEEE Transactions on Parallel and Distributed Systems (TPDS), Special Issue on Trust, Security, and Privacy. Vol. 25, No. 2, pp. 321-331. 2014.

Mahdi Nasrullah Al-Ameen, Charles Gatz, and Matthew Wright. SDA-2H: Understanding the Value of Background Cover against Statistical Disclosure. In Journal of Networks Special Issue on Selected Papers from ICCIT 2011, Vol. 7 No. 12, pp. 1943-1951. December 2012.

Mahdi N. Al-Ameen, Matthew Wright. Design and Evaluation of Persea, a Sybil-resistant DHT. In ACM Symposium on Information, Computer and Communications Security (AsiaCCS). June 2014. 

Mahdi N. Al-Ameen, Matthew Wright. Persea : A Sybil-resistant Social DHT. In ACM Conference on Data and Application Security and Privacy (CODASPY). February 2013. [sp]

Mahdi Nasrullah Al-Ameen, Mehrab Shahriyar, A. Billah. Time and Space Efficient Algorithm for Consumer's Priority Product Management. In International Conference on Computer and Information Technology (ICCIT). December 2012.

Mahdi Nasrullah Al-Ameen, Charles Gatz, Matthew Wright. SDA-2H : Understanding the Value of Background Cover Against Statistical Disclosure. In International Conference on Computer and Information Technology (ICCIT). December 2011.

Mahdi Nasrullah Al-Ameen, Md. Monjurul Hasan, Asheq Hamid, Making FindBugs More Powerful. In International Conference on Software Engineering and Service Sciences (ICSESS). July 2011.

Mahdi Nasrullah Al-Ameen. A clustered response mechanism to discover the topology of wireless sensor networks with an application to network management at faulty and operational state of nodes. In International Conference on Sensing Technology (ICST), November 2008.

Mahdi Nasrullah Al-Ameen, MD.Rakib Hasan. The mechanisms to decide on caching a packet on its way of transmission to a faulty node in wireless sensor networks based on the analytical models and mathematical evaluations. In International Conference on Sensing Technology (ICST). November 2008.

*sp: short paper/poster session

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