I was teamed-up with @blackb6a on Google CTF this time. I have solved 7 challenges alone and 3 challenges with my teammates.
In particular, Oracle is a crypto challenge with 13 solves. It has got me spending 12 hours. All in all, it was a great experience in terms of learning, but my liver hurts. This piece of writeup may be very computation intensive, just because I would like to make everything clear.