Profile / Biography

Tsukasa OI (大居　司)

Tsukasa OI (formerly, Tsukasa OOI), born in Japan on 1988, is an information security researcher/engineer.

He is awakened in information security because of a small reason and appeared in public on PacSec 2009 (as a speaker, to save money for trip to Tokyo). He continued research and participated international conferences and tech-con and he was a researcher at a leading security company in Japan for 2011-2014. But because of mental problems he threw the job and now involving information security as an amateur.

The best hope is, having fun, with everyone.

2009

• Speaker: PacSec 2009 (Tokyo, Japan)

2010

• Speaker: PacSec 2010 (Tokyo, Japan)
• Award: 1st place at Reverse Engineering Contest "Hackers' Dream" (Seoul, Korea)

2011

• Speaker: PacSec 2011 (Tokyo, Japan)
• Speaker: Black Hat Abu Dhabi 2011 (Abu Dhabi; United Arab Emirates)

2012

• Speaker: Black Hat USA 2012 (Las Vegas, United States of America)
• Speaker: FIRST Technical Colloquium Kyoto 2012 (Kyoto, Japan)

2015

• Software : ffuzzy++ (Original Developer)
• Software : ssdeep (Committer)

2017

• Activity : Security Camp 2017 lecturer (crash course theme Z2)
• Software : fast-ssdeep-clus (Original Developer)
• Software : ssdeep (Maintainer / Project Administrator)

2018

• Activity (Planned): Security Camp 2018 lecturer (crash course theme Z2)

Physical Publications

You may find some articles in some aliases. Please note that this list includes publications as an employee.

2011-2012

• Monthly Magazine: Nikkei BP "Nikkei Communication" : Inside Android Security (2011-10 to 2012-03)

2012

• Book: Nikkei BP "Android Security Bible 2013" : Chapter 1 (in Japanese)

Software Contributions

There's no many big contributions but making small patches and proposing issues.

2011

• mingw-w64
  • Fix for exception handling
• Android (as a FFRI employee)
  • Add TRUE ASLR to Android 4.0 dynamic linker (Japanese article)
    (not merged but confirmed Google already made true ASLR in development. Android 4.1 which has true ASLR was released in 2012.)

2012

• Autoconf Archive
  • Add support for latest Intel/AMD CPUs
• VMware Workstation (for Linux)
  • Add support for Linux kernel 3.5- host (on 9.0.0, Technology Preview 2012 and before)
    (This patch is improved by VMware themself for portability)

2013

• Autoconf Archive
  • Fix support for latest Intel/AMD CPUs (caused by me)
• pngcrush (Manipulation Utilities for PNG files)
  • Fix option parsing issue (on 1.7.66 and before)
• SPICE (Guest Tools for Windows)
  • Proposal for correct code-signing on 64-bit Windows platform (on SPICE Guest Tools 0.65 and before)

2014

• CoreTweet (Twitter client library for .NET/Mono platforms)
  • Fixes regarding datetime and its parsing (PR1 | PR2 | PR3)
  • Fix relating streaming APIs with GZIP compression
  • Other improvements and refactoring (PR1 | PR2 | PR3 | PR4 | PR5)
• rhash
  • Portability improvement (on 1.3.2 and before)
• Autoconf Archive
  • x86 rewrite on AX_GCC_ARCHFLAG
  • Add workaround for Clang
  • Add robustness and new options for Intel Compiler
• ssdeep
  • GPL-compatible edit distance code (Joint work with @kikairoya by clean room design + reimplementation of the well-known algorithm)
  • Fix bugs when comparing "identical" fuzzy hashes
    (2.11; The patch I sent first was incomplete; 2.12 is still corrupted)

2015

• ssdeep
  • version 2.13 : Multiple bug fixes (including critical digest comparison issue)
  • version 2.13 : Add support for big files (up to 192GiB)
  • version 2.13 : Remove size limit from stdin

Links

Twitter (Japanese)

@a4lg

Twitter (English)

@a4lg_en

Facebook (inactive)

Tsukasa OI

LinkedIn

Tsukasa OI

GitHub

a4lg

PGP Key

Fingerprint

3EA5 970D 66B0 8B8F 2E17 C80E 4953 BCBB 0B68 AB1A