Daily ideas and recent information is Here (blog, JP)

About me: Takashi Yoneuchi


Job: student of The University of Tokyo & Web Application Security Tester

Birthday: 1998/09/17

Location: Hokkaido and Tokyo

Skills, Hobbies and Interests

Computer Security

I'm interested at Web Security. I'm also a lover of a game called CTF. I'm in two teams: "dodododo" and "i81109".


I often read Japanese novels. Nowadays I'm studying Spanish hard and reading Spanish books.


I'm not good at math so much, but I purely love math <3



IBM Research - Tokyo (Internship)

As a student researcher.

SECCON Beginners CTF 2018

As a staff. I made some Web challenges for beginners.

Security Mini Camp 2018 in Hyogo

As a staff.

第15回ゼロから始めるセキュリティ入門 勉強会

As a speaker. My slide is here.

Security Mini Camp 2018 in Shikoku (Tokushima)

As a tutor.


As a reviewer. I had been looking forward to the day when this book was published because it had been a while since previous book (No. 5) was published X)

第14回ゼロから始めるセキュリティ入門 勉強会

As a speaker. My slide is here.

SECCON 2017 Finals (International)

As a member of dodododo. We won the 3rd.


SECCON 2017 Online CTF

As a member of dodododo. We won the 11th.

SECCON Beginners 2017 Kagoshima

As a speaker.

SECCON Beginners 2017 Tokyo

As a speaker.

SECCON Beginners 2017 Sendai

As a speaker.

SANS Netwars Tokyo 2017

As a participant and a member of Whitepapers. We got the 7th prize of 25 teams.

SECCON Beginners 2017 Hiroshima

As a speaker.


As a reviewer (but I made just a little contribution X-( )


As a reviewer. I highly recommend this series not only to all mathematics lovers but also to all people.

SECCON Beginners 2017 Nagoya

As a speaker.

SECCON Beginners 2017 Morikoka

As a speaker.

From 2014 to 2016

I was a high school student and made a lot of efforts for improving my handball skill :-) I made some small contribution to 数学ガール(Math Girl) as a reviewer. I love this series X-)



As a member of dodododo.

SECCON 2013 Hokkaido

As a member of the team dodododo, and we won the first. (Here)

OSC Hokkaido 2013 #osc13do

As a speaker.(Here)

Security Camp Forum 2013

As a speaker.


Security Camp 2012

As a participant.

Recent Publications

XSS in the era of *.js

XSS in the era of *.js - JS ライブラリ時代の XSS (ゼロから始めるセキュリティ入門 勉強会 #14) (in Japanese, 日本語)


Introduction: Content Security Policy (ゼロから始めるセキュリティ入門 勉強会 #14) (in Japanese, 日本語)


CSP: Content Security Policy - The History and the Future of CSP (English)