about-me

About Me

Hi! I’m Ryosuke Iwahashi (a.k.a Iwancof) enrolled in the University of Tsukuba.

I have a deep interest in low-level development and low-level security. Apart from this, I am deeply curious about various fields of engineering, mathematics, and the natural sciences.

I have organized and participated in several security events known as Capture The Flag (CTF) competitions, where I’ve won prizes at SECCON, one of the biggest CTF events in Japan. I’ve also had the opportunity to write papers on circuit-level security, further cultivating my expertise in this domain.

I often use Rust in my development work, contributing several libraries to crates.io, and developing tools for binary optimization. In addition to Rust, I am proficient in multiple programming languages, including C/C++, C#, Python, and TypeScript. I also have the skill to write assembly code for x86_64 architecture and have previously embarked on a project developing an operating system solely with assembly code.

Thank you for your time and I look forward to potentially collaborating in the future.

Writeups

• (JP) SECCON 2022 Writeup
• (JP) TSG LIVE 9 CTF Writeup
• (JP) ASIS CTF 2023 Writeup
• (JP) vsCTF 2023 Writeup
• (JP) DEFCON quals 2024 Writeup
• (JP) SECCON 2024 Quals Writeup

Links

Twitter GitHub

Portfolio

Products

• Cuber
  • Minecraft server written in Rust.
• MyFirstOS
  • My First OS written by Assembly(x86_64).
• random_struct_layout
  • A library that obfuscates the struct layout of Rust using proc-macro.
• SECR
  • Security Enhanced CPU for RISC-V.
  • Seccamp’s final deliverable.
• COJT_HW
  • The games I developed written in pure Verilog.
• Full-Scratch-C-exception-handler
  • I implemented handling of C++’s try-catch from scratch using the dwarf information emitted by the compiler.
• reina
  • Full scratch RDBMS written in Rust.
  • in development
• [minicaml]
  • Subset of OCaml

Skill Set

• Languages
  • Rust, Verilog, C/C++, C#, Assembly(x86_64), Python, TypeScript
• Security(CTF)
  • Pwn, Rev, Pentest
• Other
  • FPGA, Docker, Linux, Infrastructure

Skill Set(Detail)

• Qualification
  • 応用情報技術者(AP)
  • TOEIC(775)
• Rust
  • proc-macro
  • OS Development
  • Unsafe Rust
• C
  • C99
  • C11
• Security
  • Binary
    • Statically Analysis(Ghidra)
    • Exploits
    • GLIBC malloc, FILE struct, …
    • ELF structure
  • Pentest
    • HackTheBox
  • Low-Level
    • Circuit Level Security
• Web
  • I’m working at the large image hosting service written by Svelte and TypeScript.
• Infrastructure
  • I’m hosting several web services using Cloudflare.
  • Network(I have experience operating a network of around 300 people.)
  • Monitoring(Grafana, Log analysis)
• Linux
  • Arch Linux(about 3 years)
  • Reading kernel