A webcam presence lock for Windows that knows you from everyone else — soft dim when you leave, no-password return, hard lock on strangers.
CrySence is a webcam presence lock for Windows that knows you from everyone else. Walk away from your desk and a soft cover drops over the screen; sit back down and it recognizes your face and lifts itself — no password. If a stranger leans close to your screen, it hard-locks Windows, photographs the intruder, and alerts you. And it gets out of the way for video calls: when Teams, Zoom, or a browser call grabs your mic or camera, CrySence pauses and resumes afterwards.
100% local, auditableEverything runs on your machine — face detection (OpenCV YuNet), face recognition (SFace, local ONNX models), and intruder captures never leave your PC. No telemetry, no account, no network calls except the update check to GitHub and the alert channels you configure yourself (Windows toast always on, plus optional ntfy / SMTP / Telegram / Resend). Your face is stored only as a numeric embedding, never as images, and the author invites you to read the ~1,000 lines yourself before trusting the binary.
vibe-coded, openlyThe author's own launch copy says it plainly: "I vibe-coded a webcam presence lock that knows me from everyone else" and "So I built one that locks based on whether you're actually there, with Claude Code over a few evenings. ~1,000 lines of Python, open source." Eleven releases through v0.3.7 (2026-09-25) show it wasn't a one-evening throwaway — the changelog reads like a real hardening story: memory leaks in camera drivers, emergency unlock via Ctrl+Alt+Shift+U, hourly update checks.
Honest limitationsThe author puts the caveats up front, which we appreciate: the soft cover is privacy not security (Task Manager can kill it — the hard Windows lock is the real lock); no liveness detection yet (a good printed photo could pass 2D recognition); Windows only.
Under the hoodTech stack per the author: Python (~1,000 lines), OpenCV YuNet + SFace for detection/recognition, CustomTkinter GUI with a first-run setup wizard, strictness sliders, camera picker and live preview. MIT licensed; run from source or grab the per-user installer from GitHub Releases (unsigned, so SmartScreen will warn — or run from source, which the author recommends).
Who it's forAnyone who works in open offices, coworking spaces, or cafes; privacy-minded folks who like local-first software; and a great demo that vibe coding can produce real, working security tooling — with its limitations honestly disclosed.