After participating in the CSA challenge, I was approached via email. First there was a phone interview, then there was an interview of 2 and a half hours. + At the phone interview, I was asked about my background and asked what was the most difficult challenge I solved and how I solved it. + At the actual interview, I set in a small room with the interviewer. He asked about my background, what interests me in the course and so on (Interview questions bellow). This was followed by 3 sets of questions: 1. notepad implementation a. with O(n) access b. with O(1) access 2. Network protocols: a. given a protocol, what attacks can be made? b. how can we prevent them and what are their limits? c. given an extension to the protocol, how can we spread the attack or prevent it 3. Questions on the computer (about 30-40 minutes) All in all the interviewer was very nice and understanding, enough time was given to answer and discuss the questions.