Research areas

Critical infrastructure protection

Infrastructures, such as the electric power grid, oil and gas distribution and pipelines, transportation systems, telecommunications systems, and information systems are critical for our nation's operation. Computer science plays a vital role in protecting these infrastructures from harm. These systems are naturally distributed, thus, are very complex; in fact, they are typically interconnected sets of systems. The distributed structure makes them vulnerable to attack at many places and in many forms, including physical and cyber-based, singly or in combination with each other.

In order to assure the continued functioning of these systems, their complexity requires expertise in all aspects of possible attacks. This, therefore, includes not only protecting against physical attack and damage but also the integrated reliability and security of such large-scale systems, where an attack at one point can have drastic consequences over a much broader target area, leading to cascading failures. Further, the diversity of these systems requires expertise in many different domain areas including "hard" engineering such as civil engineering, electrical and computer engineering, and petroleum engineering, as well as computer science, software engineering, economics, social issues, and cyber security.

One of the main vulnerabilities of modern power distribution grids is their susceptibility to cascading failures from successive losses of transmission lines. Recent developments in power research have lead to “Flexible AC Transmission System” (FACTS) devices that modify the power flow locally within a power grid. Embedded computers within the FACTS devices form a distributed computing system that can make coordinated, rapid, changes to the power flow in the grid. If a particular transmission line becomes overloaded due to a failure of a power source, the embedded computers can re-balance the power flow before a massive, cascading power failure can occur resulting in a blackout.

Possible threats to the survivability of the system can come not only from physical disruptions, but also from security intrusions in which a hacker may attempt to confuse the distributed control algorithms. These threats are minimized by enforcing correct operation of the computing system through ensuring that its actions correspond to the correct physical rules that govern power flow. Integrating computer control with a complex physical system requires expertise in both the computing research and power research fields. The exploratory research is an interdisciplinary collaboration. Overall scope of the project is to examine evolving system stability, economic issues, certification of the control systems and power grid design. Our current progress and technical information on the project can be found on the project's webpage. Our current effort is in constructing a Hardware In the Loop (HIL) FACTS interaction laboratory to study FACTS interactions and response to computer and power system failures.

Attacks in Sensor Networks: Many sensor network applications, such as border security, emergency response operations in the disaster environment, and battlefield monitoring, run in untrustworthy environments and require secure communication against different types of attacks. The attacks, such as black hole attack and wormhole attack, cause an existing route to be broken or a new route to be prevented from being established. We propose a hierarchical secure routing protocol for detecting and defending against black hole attacks and are working on detecting collaborative attacks.

Secure Aggregation in Sensor Networks: Wireless sensor networks (WSN) create a constant stream of data which flows from the sensing location towards an interface with the world - usually a more powerful computer, called base station. Since all communication is done via wireless radio links, security is an especially important topic. Most sensors run from a non-renewable energy source, such as batteries, and ways to increase the life of the network are constantly thought after. Aggregation or the combining of several readings along the routing path has been shown to decrease the number of radio transmissions, generally the most expensive operation in a WSN. How to handle aggregation if security is required poses a new problem. There are two central issues for secure aggregation in WSN. At each aggregation point, it is important to ensure that the actual reading where used to calculate the aggregate. Due to the nature of WSN, infiltration of malicious sensors is possible and they could falsify an aggregate result. If data security is required and standard encryption schemes are used, only constant decryption, aggregation, encryption allows for security and aggregation. This slows down the data collection process and consumes additional energy. Encryption schemes are needed which allow for aggregation without decryption, only the base station needs to be able to decrypt the aggregate result. We are proposing some algorithms to handle secure aggregation in WSN.

Key Management in WSN: Sensor nodes have limited computation and battery power, and are not very reliable. A sensor network needs to be secure against eavesdrop when it is deployed in hostile environments. In order to provide security at low cost, symmetric key based approaches have been proposed. An elliptic curve cryptography based approach has been implemented to facilitate the public-key cryptography. However, the scheme become ineffective in terms memory usage, communication time and energy required with the rapidly growing network size. We propose an Energy and Communication Efficient Group key management (ECEG) scheme which reduces the usage of memory, communication and energy in sensors.

Data Stream Security in Wireless Sensor Networks: Wireless sensor networks can generate large amounts of data; naturally that data needs to be secured. Sensors can become corrupted due to the physical environment in which they are deployed, so one important goal in wireless sensor networks is ensuring that all data is correct. Data security in wireless sensor networks encompasses data confidentiality, data integrity, and data availability. Since data transmission is via a wireless medium anybody tuned to the same frequency can intercept messages. Moreover, an attacker who simply listens to the transmissions is eavesdropping. Having certain information, an attacker can inject false messages into the network. Additionally, an attacker can spoof messages by first intercepting the message, modifying it and then re-insert the message into the network. In addition, when data are generated in sensor networks, high-speed data streams travel through the network. Traditional security approaches are often unable to keep up with the rates of the streams or they introduce overhead, which shortens the life of the network. We are particularly interested in providing a secure data processing environment which is lightweight in computational and time complexity to allow for fast processing of data, yet still provides a reasonable amount of protection against a variety of attacks, such as changing data in midstream and overhearing transmissions of packets.

Integrity Preserving Aggregation: Data aggregation is a main factor in reducing energy consumption by eliminating data redundancy and reducing communications overhead. Secure data aggregation  in sensor networks is to provide data aggregation and the energy savings while ensuring data security. Security in sensor networks requires new approaches due to the limitations of sensors and their limited computing power. Implementations in hostile environments face the additional problem of malicious corruption by attackers. When in-network aggregation is used, the base station needs to be able to trust that any corruption during the aggregation process is detectable or preventable, and all non-corrupt sensor nodes need to be sure that their readings were properly applied to an aggregate reading. The focus of this work is on the “How can a sensor network calculate an in-network aggregate and ensure that the base station is assured that the aggregate is correct or is able to identify an aggregator which reports an incorrect result”. We propose the use a secure multiparty computation (MPC) protocol. An MPC protocol allows the secure computation of almost any function with a few additional properties.

Power-aware Secure Routing Protocols: Secure routing is one of the most important aspects in sensor networks. There are several examples of attacks on routing in sensor networks, such as the routing packet could be captured or the information in the packet could be tampered, the adversary might insert spurious message in sensor networks. However, much research has been focused on making sensor networks feasible and useful, and has not been concentrated on security and therefore, the traditional route discovery algorithms are assumed to be used in the trusted environment. The performance of a protocol will be measured based on the degree of overhead associated with a given security measure and energy consumed. The power aware protocol will be modified to include secure key management and trust levels. The result will be a secure, trusted, adaptive and scalable routing protocol.

Incentive based routing protocol in MANET's: The focus of this research is to handle routing issues in Mobile Ad Hoc Networks. The main idea is to use Incentive Based Routing Protocol to avoid selfishness among mobile hosts by providing incentives to pass the information among them. By modeling the Network in Directed Weighted Graphs, we are designing a virtual currency function to find the cost/weight between two Mobile Hosts (MHs) and use this cost as an incentive for the intermediate nodes to route the information packet to the destination requester node. We will use game theoretical models to optimize the cost.

Privacy Ensured Service Discovery in MANET's: Research involves in developing a protocol that ensures private details of the mobile hosts remains secured. We are considering an ad hoc network with ubiquitous services and users. Users will not reveal their private details in the process of discovering the service in the network. Also, the service provider will not publish its services. Protocol also considers the trust issues among the participating nodes in the network

Replication issue in P2P: Here we are working on designing replication and caching schemes to handle the dynamic behavior of these mobile peers. We also address the resource constraints at these peers in order to design adaptive and dynamic replica allocation schemes. We have proposed some replication schemes which uses incentive based models for data replication.