Hiroyuki Katsura

PhD student at The University of Tokyo

Hiroyuki Katsura (桂 宏行)

I’m Hiroyuki Katsura, 2nd-year PhD student, supervised by Naoki Kobayashi in 3-year PhD course at Dept. of Computer Science, Graduate School of Information Science and Technology of The University of Tokyo.


Research Interests

My main research interest is to propose analyses to enhance software reliability. This includes:






Teaching Assistants

I have been a teaching assistant three times at Dept. of Information Science, School of Science, The University of Tokyo.


CTF (Capture The Flag)

I have been playing CTFs as a member of an university team TSG whose team members are all from The University of Tokyo. Sometimes, I join in larger teams to compete large contests like DEFCON. I mainly play pwnable (binary exploit) and reversing.

Here are some of my achievements in CTF contests. Note that due to the collaborative nature of CTFs, my individual contribution varied from one CTF to another :)

My CTF Challenges

I have created a lot of CTF challenges so far from easy one to harder one: please refer to this page (TBD).

My favorite ones are

Random collection of my writeups of my challenges:

Other Activities


ISUCON is a Japanese contest held by LINE corp, where participants aim to fine-tune a given web service within set regulations. I have played ISUCON six times as a member of FetchDecodeExecWrite.

Security Camp


Apart from researching, I’m a big fan of