Biblio

The behavior of a differentially private system is governed by a parameter epsilon which sets a balance between protecting the privacy of individuals and returning accurate results. While a system owner may use a number of heuristics to select epsilon, existing techniques may be unresponsive to the needs of the users who's data is at risk. A promising alternative is to allow users to express their preferences for epsilon. In a system we call epsilon voting, users report the parameter values they want to a chooser mechanism, which aggregates them into a single value. We apply techniques from mechanism design to ask whether such a chooser mechanism can itself be truthful, private, anonymous, and also responsive to users. Without imposing restrictions on user preferences, the only feasible mechanisms belong to a class we call randomized dictatorships with phantoms. This is a restrictive class in which at most one user has any effect on the chosen epsilon. On the other hand, when users exhibit single-peaked preferences, a broader class of mechanisms - ones that generalize the median and other order statistics - becomes possible.

Controller Area Network is the most widely adopted communication standard in automobiles. The CAN protocol is robust and is designed to minimize overhead. The light-weight nature of this protocol implies that it can't efficiently process secure communication. With the exponential increase in automobile communications, there is an urgent need for efficient and effective security countermeasures. We propose a support vector machine based intrusion detection system that is able to detect anomalous behavior with high accuracy. We outline a process for parameter selection and feature vector selection. We identify strengths and weaknesses of our system and propose to extend our work for time-series based data.

Swarm Intelligence (SI) algorithms, such as Fish School Search (FSS), are well known as useful tools that can be used to achieve a good solution in a reasonable amount of time for complex optimization problems. And when problems increase in size and complexity, some increase in population size or number of iterations might be needed in order to achieve a good solution. In extreme cases, the execution time can be huge and other approaches, such as parallel implementations, might help to reduce it. This paper investigates the relation and trade off involving these three aspects in SI algorithms, namely population size, number of iterations, and problem complexity. The results with a parallel implementations of FSS show that increasing the population size is beneficial for finding good solutions. However, we observed an asymptotic behavior of the results, i.e. increasing the population over a certain threshold only leads to slight improvements.

The symmetric block ciphers, which represent a core element for building cryptographic communications systems and protocols, are used in providing message confidentiality, authentication and integrity. Various limitations in hardware and software resources, especially in terminal devices used in mobile communications, affect the selection of appropriate cryptosystem and its parameters. In this paper, an implementation of three symmetric ciphers (DES, 3DES, AES) used in different operating modes are analyzed on Android platform. The cryptosystems' performance is analyzed in different scenarios using several variable parameters: cipher, key size, plaintext size and number of threads. Also, the influence of parallelization supported by multi-core CPUs on cryptosystem performance is analyzed. Finally, some conclusions about the parameter selection for optimal efficiency are given.

In this paper, we propose techniques for combating source selective jamming attacks in tactical cognitive MANETs. Secure, reliable and seamless communications are important for facilitating tactical operations. Selective jamming attacks pose a serious security threat to the operations of wireless tactical MANETs since selective strategies possess the potential to completely isolate a portion of the network from other nodes without giving a clear indication of a problem. Our proposed mitigation techniques use the concept of address manipulation, which differ from other techniques presented in open literature since our techniques employ de-central architecture rather than a centralized framework and our proposed techniques do not require any extra overhead. Experimental results show that the proposed techniques enable communications in the presence of source selective jamming attacks. When the presence of a source selective jammer blocks transmissions completely, implementing a proposed flipped address mechanism increases the expected number of required transmission attempts only by one in such scenario. The probability that our second approach, random address assignment, fails to solve the correct source MAC address can be as small as 10-7 when using accurate parameter selection.