M.Ing. (Electric and Electrical Engineering) / From the day the first 'apple' was eaten, a species of people existed that wants to misuse other people, This species is normally the first to use new technology to their advantage. It is essential for our own security to restrict the boundaries of their playing-field and to fill the field it self with potholes. This however should be a continuous process, for their dexterity tends to evolveas fast as new techniques are mastered. Firstly this thesis entails the analysis of the boundaries of the playing field of authentication systems without security. The boundaries of authentication systems with security is established with a unique technique. Concluding the first part of the thesis, a new method of code designing for this playing-field is proposed. Reordering the potholes on the playing-field is the subject of the second part of the thesis. Anew public key system is described for this purpose. A novel implementation of insertion/deletion error correcting codes is presented in this new system. To conclude the thesis, a thorough analysis of this public key system is presented.

M.Ing. / The transmission of digital data at higher data rates and greater reliabilities is becoming increasingly more important in the society of today. The usage of, especially wireless digital data, is increasing at an alarming rate, and the need arises for more bandwidth to be made available for this purpose. Hence, the need arises to optimise and expand the usage of bandwidth currently under use. Existing wireless channels, such as the commercial FM service, need to be re-evaluated and unused bandwidth needs to be developed and used as close to capacity as possible. In this dissertation, a study was launched to develop the FM SST (Supplementary Signal Transmission) commercial analog service as a simplex digital channel that can commercially be used to transmit a myriad of digital data. With the help of a commercial FM radio channel, digital data was transmitted using a number of different modulation schemes to obtain channel measurements for the FM SST channel. The modulation scheme that performed the best, given certain criteria, was GMSK. This raw information was then used to extract first and higher order statistical information from the channel, in order to parameterise discrete channel models, based on a Markov process. The channel models that were used were the Gilbert, GilbertElliott and Fritchman channel models. These channel models were then tested according to their iirst and higher order statistical data to evaluate their effectiveness in modelling the error process on the FM SST channel. It was found that the channel model best approximating the real channels was the Gilbert channel. Once satisfactory results were obtained, these discrete channel models were then used to evaluate various error correction schemes for their ability to correct burst errors on the FM SST channel. From the various schemes evaluated, a (63,39) BCH with an interleaver of index 4 was found to perform the best. The purpose of which is to transmit digital data at the highest data rate possible and at the same time having a bit error rate less than lxl0-6.

An automatic repeat request (ARQ) scheme with memory and soft error detectors has been recently proposed by Benelli. Its performance was studied mainly through computer simulation. In this thesis, a generalized version of this ARQ scheme is examined. The selection of certain thresholds and weights to minimize the bit error rate in systems using a fixed number of packet repeats is considered. The evaluation of the average number of transmissions per packet in systems in which negatively acknowledged packets are retransmitted until successfully received is described. Finally, the performance of the memory ARQ scheme with forward error correction is analyzed. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Campus Area Networks (CANs) are a subset of enterprise networks, comprised of a network core connecting multiple Local Area Networks (LANs) across a college campus. Traditionally, hosts connect to the CAN via a single point of attachment; however, the past decade has seen the employment of mobile computing rise dramatically. Mobile devices must obtain new Internet Protocol (IP) addresses at each LAN as they migrate, wasting address space and disrupting host services. To prevent these issues, modern CANs should support IP mobility: allowing devices to keep a single IP address as they migrate between LANs with low-latency handoffs. Traditional approaches to mobility may be difficult to deploy and often lead to inefficient routing, but Software-Defined Networking (SDN) provides an intriguing alternative. This thesis identifies necessary requirements for a software-defined IP mobility system and then proposes one such system, the Software-Defined Mobile Campus Area Network (SD-MCAN) architecture. SD-MCAN employs an OpenFlow-based hybrid, label-switched routing scheme to efficiently route traffic flows between mobile hosts on the CAN. The proposed architecture is then implemented as an application on the existing POX controller and evaluated on virtual and hardware testbeds. Experimental results show that SD-MCAN can process handoffs with less than 90 ms latency, suggesting that the system can support data-intensive services on mobile host devices. Finally, the POX prototype is open-sourced to aid in future research.

The General Direction Routing Protocol (GDRP) is a Wireless Sensor Network (WSN) multi-path routing protocol which abstracts localization information (commonly GPS coordinates) into relative direction information in order to perform routing decisions. By generating relative direction information GDRP is able to operate with fewer precision requirements than other protocols. This abstraction also allows the integration of other emerging hardware-based localization techniques, for example, Beamforming Sensor Arrays. GDRP does not specifically address the next hop a packet should take, but instead specifies a direction it should travel. This direction abstraction allows for multiple paths to be taken through the network thus enhancing network robustness to node mobility and failures. This indirect addressing scheme also provides a solution to sensor node unique identification. GDRP is simulated in a custom simulator written in Java. This simulator supports interfaces for multiple protocols for layers 1, 2, 3, and 7 of the OSI model. For performance comparisons, GDRP is compared against multiple WSN routing protocols. GDRP operates with a significantly lower setup cost in terms of bytes transmitted and a lower setup latency for networks of varying sizes. It also demonstrates an exponentially lower routing cost when compared to another multi- path routing protocol due to a more efficient packet propagation in the network.

Recent advancements in Large Scale Integration Technology have made available devices, such as microprocessors, analog gates and “three state” logic, that provide the designer with a wide range of possibilities in the design of telecommunication systems. A microprocessor and analog gates are utilized in this design to demonstrate the feasibility of implementing a flexible Telecommunication System. The microprocessor is programmed to control, through software, the system functions. The feasibility of systems highly adaptable to the needs of individual subscribers is thus demonstrated.

Mobile devices have advanced tremendously during the last ten years and have changed our daily life in various ways. Secure pairing of mobile devices has become a significant issue considering the huge quantity of active mobile device connections and mobile traffic. However, current commonly used file sharing mobile applications rely on servers completely that are always targeted by attackers. In this thesis work, an innovative mechanism is proposed to generate symmetric keys on both mobile devices independently from a shared movement in arbitrary pattern, which means no server needs to be involved and no data exchange needed. A secret wireless-communication channel can then be established with a particular network strategy.

No description available.

As the functionality that current computer network can provide is becoming complicated, a traditional router with application-specific integrated circuit (ASIC) implementation can't satisfy the flexibility requirements. Instead, a programmable packet forward system based on a general-purpose processor could provide the flexibility. While this system provides flexibility, a new potential security issue arises. Usually, software is involved as the packet forward system is programmable. The software's potential vulnerability, especially as to the remote exploits, becomes an issue of network security. In this thesis work, we proposed a software stack overflow vulnerability on click modular router and show how a disastrous denial-of-service attack on click modular router could be triggered by a single packet. In our research work, click modular router runs on Linux operating system based on general-purpose hardware. We actually showed that even a software router run within a modern operating system's protection is vulnerable by elaborate attack. And we checked the possible stack protection mechanisms on modern OS based on general-purpose hardware and proposed a possible stack protection mechanism for embedded OS.

Optical packet switching networks are the foundation for next generation high speed Internet and are fast becoming the norm rather than an option. When such high speed optical networks are taken into account, one of the key considerations is packet buffering. The importance of packet buffering plays an even bigger role in optical networks because of the physical and technological constraints on the buffer sizes that can be implemented. Existing protocols, in many real world scenarios do not perform well in such networks. To eliminate such scenarios where there is a high possibility of packet loss, we use packet pacing. The proposed pacing scheme aims to reduce or eliminate packet losses arising from packet bursts in small-buffer networks. This thesis deals with a proposed hardware design and implementation of the packet pacing system on a NetFPGA. Our results show that the packet pacer can be implemented with a low overhead on hardware resources.