Changwan Park
Hello! I use id pcw109550, diff, or diff72840089. You can call me diff. I build stuff in the morning/afternoon, break stuff in the evening, and make things decentralized at night.
Contact me at pcw109550 at gmail.com or at X, LinkedIn, GitHub.
Interests: Blockchain, Cryptography, Virtual Machines, Rollups
Experience
Software Engineer @ Test in Prod, 2023.3 ~
- Contribute to Optimism - OP Stack
- Consensus Layer
- Execution Layer
- Maintaining OP-Erigon, providing efficient storage and faster sync.
- Settlement Layer
- Polishing Asterisc, a fault-proof VM which proves execution of a RISC-V program.
- Keywords: Blockchain, Optimism, Distributed Ledger Technology, Cryptography
Software Engineer @ Sendbird, 2021.3 ~ 2022.5
- Developed Sendbird Calls
- Keywords: Python, C++ Backend Development / Media Server / Load Testing / WebRTC
Intern @ Crazing Lab, 2020.3 ~ 2020.8
- Developed ML inference pipeline for autonomous robots
- Keywords: Object Detection / Pose Estimation / SLAM
Honors And Awards
HITCON CTF Finals
DEF CON CTF Finals
SECCON CTF International Division Finals
- 2023: Invited as a member of Team HK Guesser, ranking in 5th
CODEGATE CTF University Division Finals
- 2023: Awarded as a member of Team KAIST GoN, ranking in 1st(Minister of Science and ICT Award), Media
- 2022: Awarded as a member of Team KAIST GoN, ranking in 1st(Minister of Science and ICT Award), Media
Cyber Conflict Exercise General Division Finals
- 2023: Awarded as a member of Team NoG, ranking in 3rd(National Research Council of Science and Technology Director Award)
Korea Crypto Analysis Contest(암호분석경진대회)
- 2024: Awarded as a leader of Team 염소가죽, ranking in 3rd(Defense Security Agency Commander Award)
- 2023: Awarded as a leader of Team 염소가죽, ranking in 2nd(Defense Intelligence Agency Director Award)
- 2022: Awarded as a leader of Team KAIST GoN, ranking in 1st(Minister of Defense Award), Media
Korea National Crypto Contest(국가암호공모전) Div2(Problem Solving)
- 2019: Awarded as a leader of Team KAIST GoN, ranking in 2nd(KISA Director Award)
- 2018: Awarded as a member of Team KAIST GoN, ranking in 1st(Korea NIS Director Award)
- 2017: Awarded as a leader of Team KAIST GoN, ranking in 3rd(Korea NSRI Director Award)
Projects
CTF Writeups, 2018 ~
- Wrote 50+ CTF writeups in fields of {Cryptography, Blockchain, Reversing}
CTF Challenge Author, 2019 ~
- Wrote 20+ CTF challenges in fields of {Cryptography, Blockchain, Reversing}
- Authored CTF: CODEGATE {2020, 2024}, WACON {2022, 2023}, Whitehat {2019, 2020, 2021, 2022}
Education
KAIST, 2017 ~ 2025(Expected)
- Undergraduate. Major: Electrical Engineering, Double Major: Computer Science
UC Santa Cruz, 2019 Summer