Walter Niemi

 I care deeply about connection. Family, community, and clarity shape how I approach everything I build and study. That sense of belonging stays at the center of my work, whether I’m working with young people or exploring new frontiers in technology.
 

I build cybersecurity systems.

LobbyShield is a route-aware, session-aware defense system built directly into the LobbyChess application stack. It combines pre-routing enforcement, manifest-driven positive security, identity-aware rate limiting, enriched telemetry, behavioral threat scoring, WebSocket abuse controls, and a live operator control loop for containment, benign labeling, and release actions. It is a compact internal SIEM/XDR for a single application. 

The system treats the application as a known-good surface: legitimate routes, methods, assets, and realtime channels are explicitly defined, while impossible paths, malicious probes, auth abuse, and protocol misuse are blocked or rejected by policy. On top of that, LobbyShield scores behavior across sessions, users, and IPs, measures telemetry quality, and gives operators a modern investigation console with durable response actions. Passwords are protected with Argon2id, sessions rotate on authentication, admin secrets moved out of URLs and into Authorization headers, and realtime chat/game channels are protected with rate limits, size caps, schema validation, and sanitization. 

What excites me most is building security that is both serious and usable: deterministic when the app should say “no,” behavioral when context matters, and fast enough to work inside a live product without turning security into friction. I’m especially interested in application defense, realtime abuse prevention, operator-driven response systems, and security interfaces that make investigation feel clear, modern, and actionable.