UIUC has one of the top engineering and computer science programs around the world. We have world-class faculty in various research areas and the PhD program is expanding. You can find more information about the CS department. In addition, CS Rankings is a very useful website to search for active faculty members in different research areas in computer science and computer engineering.
Applying to PhD programs is very different from applying to undergraduate or masters programs. For undergraduate and masters programs, you should care about the ranking of the school (a lot). In contrast, the most important thing when selecting a PhD program is choosing your advisor. PhD programs are more like jobs than school: you will spend the vast majority of your time creating new knowledge with your colleagues and advisor, not attending classes. Thus, as a PhD student, you want to choose an advisor who is working in an area you feel passionate about, because you will spend several years working very hard with them.
I am always looking for passionate and hard-working students to join my research group. The most important quality I look for in students is self-motivation: as a PhD student you need to take charge and proactively drive your own research agenda. I also like students who are energetic and curious, which are critical qualities to identify interesting research problems and find new solutions. In terms of technical skills, I expect students to be competent programmers (web, networking, mobile systems), but you don't need to be a super-hacker to succeed as a PhD student. In addition, my research area involves extensive data analytics. I expect students to have basic knowledge in statistcs.
The best thing to do is to read several of my recent papers, and then write me a brief email (with your CV attached) explaining: 1) which papers you like and why, 2) why you want to get a PhD, and 3) what research problems you are interested in. Please understand that I receive a lot of unsolicited emails from prospective students, so I may not be able to respond to all inquiries.
Keep in mind that my research focuses on security and privacy in the web and mobile systems. I am also interested in data mining and machine learning. If you aren't interested in those areas, then I am not the right advisor for you. If you haven't been admitted to UIUC, I suggest you going through the application process first. You can mention my name in your application so that I can easily find your case.
Absolutely! I always enjoy working with Masters/Undergraduate students who are interested in doing research. If you are already enrolled in UIUC, the best way of action is to take my class. Students who excel in class and actively participate have the best chance to join my lab to work on real research projects.