Sungjun Lee
Security Researcher & Engineer
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Experience
Columbia University
Graduating May 2026
M.S. in Computer Science (Computer Security)
Focusing on Security, Cryptography, Networks, and Private Systems.
- Formal Verification
- Ethical AI
Software Engineer
Mar 2023 - Feb 2024
Sole Proprietor
Architected and deployed a full-stack homestay platform with REST/GraphQL APIs and a LightFM recommendation engine. Managed via Render.
- Django
- PostgreSQL
- LightFM
Stony Brook University
Graduated Dec 2022
B.S. in Computer Science
Magna cum laude, Dean's List for all semesters.
Software Engineer
May 2021 - Nov 2021
MAGE Production
Developed a Korean-English translator for culinary. Built crawlers and pre-processed 10k sentences for
training.
- Crawlers
- NLP
Software Engineer
Oct 2020 - Feb 2021
AIGHTEN
Led simulation team for training data collection. Developed desktop app using PyTorch, reducing errors in
thermal detection by 70%.
- PyTorch
- Java (Dahua SDK)
Information System Technician
Sep 2017 - May 2019
72nd Infantry Division, ROK Army
Deployed security policies across 10 edge routers and 300 endpoints, securing data centers during a camp relocation. Recognized as Special Force member (Top 5%).
- Network Security
- Firewalls
Projects
Phishing Detection
Privacy-first Chrome extension for Gmail detecting phishing via a hybrid Naive Bayes ML model and heuristics.
- JavaScript
- Machine Learning
- VirusTotal API
Formal Verification
Formally verified Resilience4j's CircuitBreakerStateMachine using JBMC. Proved 8 critical properties including safety, liveness, and functional correctness.
- JBMC
- Java
- Model Checking
German Gym Bros
Developed for Hacking for Defense (2nd Cavalry Regiment). Full-stack mobile web app with an LLM-powered chat interface for automated squad-level planning.
- TypeScript
- React
- Python
- AI Integration
Strong Wrapped
Generates "Spotify Wrapped" style workout statistics from Strong app data. Features purely client-side CSV processing for privacy.
- React
- TypeScript
- Framer Motion
- Recharts
Citation Service API
Restful API for managing media resources and generating citations in MLA, APA, and Chicago formats.
- Java
- Spring Boot
- Google Cloud SQL
- Maven
Browser Fingerprinting
Automated analysis tool using Selenium to collect and study browser fingerprints to identify tracking vectors.
- Python
- Selenium
- Data Analysis
P2P Blockchain Network
A distributed PoW blockchain built from scratch. Features a custom TCP gossip protocol, concurrent mining nodes, disjoint-set fork resolution, and a React network explorer.
- Python
- Distributed Systems
- React
COVID-19 Testing Manager
Full-stack web application for lab technicians to manage pooled testing and for employees to check results.
- Node.js
- Express
- MySQL
- Bootstrap
Google Machine Learning Bootcamp
Selected from 3,000+ applicants. Completed Andrew Ng's Deep Learning Specialization and specialized in TensorFlow for 4 months.
- Deep Learning
- TensorFlow
- Keras
Public Safety Alerts Analysis
Analyzed South Korean COVID-19 alerts to study evolving social distancing guidelines and their impact on public behavior.
- API & Crawling
- Statistics
- Data Visualization
DDoS Attack Detection with BiLSTM
Analyzed 7 days of network traces. Achieved 98% accuracy with BRNN-LSTM models on 1M packets, highlighting context importance.
- Deep Learning
- LSTM
- Network Security
Academic & Research
XAI at Columbia University
Jan 2026 - Present
Designing a framework that shifts LLM auditing from correlation to causation to enforce real-time data minimization.
- Causal Inference
- LLM Auditing
Course Assistant
Jan 2026 - Present
AI for Computer Security (COMS 4995). Maintaining AuditZoo, an agent framework with built-in program abstractions.
- AI Security
- AuditZoo
Columbia SNL
Sep 2025 - Dec 2025
Analyzing passive DNS traces to detect DNS-based data exfiltration via subdomain encoding and query patterns.
- DNS Security
- Subdomain Encoding
Stony Brook University
Feb 2017 - Jun 2017
Undergraduate Teaching Assistant for Data Structures. Tutor for Applied Calculus II and Applied Linear Algebra.
- Data Structures
- Teaching