I would like to give special thanks to my examiner, Panos Papadimitratos, and my supervisor, Hongyu Jin, for all their support be it understanding, suggestions or guidance during all the phases of this work from the beginning until the end of the work. I would also like to thank people in Networked Systems Security Group at KTH who gave me commends and ideas to improve my work. Last but not least, I would like to thank Tattaton Mettaphun, Boonyakiat Rungsiwothinan, Wichapong Kua-Arun, Surapat Somsri, Nonthawun Junsrisuk, my family and my girlfriend who supported me during my endeavour of studying. Without their support, my Master's degree could not have been successfully completed.