Application Security & Systems Engineer | C++17, Python, Linux Graphics, Emulation & Defensive Security.

• ValveSoftware/gamescope — Linux gaming session compositor:
  • Addressed Vulkan/PipeWire NV12 storage image capability checks on NVIDIA drivers to eliminate green screen corruptions during Steam Remote Play.
• ValveSoftware/Proton — Steam Play Windows compatibility tool:
  • Corrected DriverStore directory case-handling and file descriptors to avoid Linux filesystem case collisions and DLL resolution failures.
• AnyPS5 — PS5 compatibility layer and translation tooling:
  • Implemented sceSysmoduleIsLoadedInternal module lifecycle state tracking (merged upstream).
  • Submitted FreeBSD tgammaf floating-point precision fix with unit tests.
• Linux Kernel (staging) — Submitted mutex guard refactoring (guard(mutex)) and checkpatch cleanups to IIO subsystem maintainers.
• GitHub Advisory Database — Security vulnerability documentation improvements for CVE advisories.

• ast-guard (AppSec / SAST) — Lightweight AST-based Static Application Security Testing scanner in Python. Generates SARIF 2.1.0 output for native GitHub Code Scanning integration and automated CI security gates.
• security-labs (Cybersecurity / Defensive Systems) — Portfolio of defensive security tools: socket port scanner, authentication log analyzer, Linux host hardening auditor, dependency CVE checker, and intentionally vulnerable test lab.
• game-dev-labs (Systems Architecture / C++17) — Modular game engine architecture: cache-friendly Entity Component System (ECS), 2D Separating Axis Theorem (SAT) physics, procedural dungeon generation with A* pathfinding, and fixed-timestep state machine.
• mini-projects (Backend Systems Engineering) — Core backend systems portfolio: in-memory C++17 key-value store, sliding-window rate limiting engine, asynchronous task queue, and hardened FastAPI URL shortener.
• secure-api (Backend / Defensive AppSec) — Hardened REST API demonstrating defensive engineering: Argon2id password hashing with timing attack mitigations, anti-IDOR authorization scopes, sliding-window rate limiting, HTTP security headers, and OWASP API Top 10 threat models.
• reconflow (Offensive Security / CLI) — Modular reconnaissance CLI for subdomain enumeration, passive DNS aggregation, and live host probing. Published on PyPI with automated CI releases.
• secret-scanner (DevSecOps / Tooling) — High-speed scanner detecting leaked credentials, private keys, and high-entropy strings across filesystems and Git history using Shannon entropy analysis.
• AnyPS5-Launcher (Desktop / Reverse Engineering) — Modern desktop game hub, ELF diagnostics analyzer, and input configurator for the AnyPS5 compatibility layer.

• Languages: C++17/20, Python 3, Java, Bash, SQL, JavaScript
• Security & Cryptography: SAST/DAST, Threat Modeling, OWASP Top 10, SARIF 2.1.0, Argon2id, JWT, Anti-IDOR, Network Reconnaissance
• Systems & Graphics: Linux Kernel, POSIX Sockets, Vulkan/PipeWire basics, Git internals, CMake, Docker, Multiprocessing
• Frameworks & Storage: FastAPI, SQLAlchemy, SQLite, Redis, Apache ZooKeeper, Clang/GCC, LLVM/AST

• GitHub: @ErenYeager1836