Admission in top tier US universities after graduation from University of Delhi

I have just completed my 3 year bachelors from Kirori Mal College, University of Delhi in applied physical sciences. Even though my course isn't quite reputed in technical industry, I managed to get a job in a Big 4 company for a cyber security profile. I have a research interest in applied cryptography and want to do my masters in computer sciences from a top tier US university. I have 4 years to prepare before I finally apply. What should I do? Also, will doing a Msc program help improve my chances for admission? My aggregate percentage for under graduation is 73% (WES equivalent 3.7).

Which universities can I aim for?