Problem
Traditional chat servers store messages on databases and have access to unencrypted payloads, risking data leaks and eavesdropping.
Full-Stack / Cybersecurity Project Build
Umbra
Zero-knowledge, end-to-end encrypted ephemeral chat application utilizing WebCrypto API and Go WebSockets.
Role
Project Manager & Full-Stack Developer
Year
2026
Stack
Go + SvelteKit
Solution
Umbra encrypts all messages in the browser before sending them to a database-free Go relay server, ensuring the server only forwards ciphertext and destroys all ephemeral room data on disconnect.
Overview
What I Built
Umbra is a zero-knowledge, end-to-end encrypted chat application. It generates cryptographic keys in the browser memory using the WebCrypto API (ECDH P-256 for key exchange, AES-256-GCM for encryption, and ECDSA for signing). The backend is built with Go (Golang) and WebSockets, relaying only encrypted ciphertext. All room data is stored in-memory and completely destroyed once users disconnect.
Technical Highlights
Engineering Notes
ECDH P-256 key exchange on client side
AES-256-GCM encryption + integrity check
Go + Fiber + Gorilla WebSocket backend
Azure Container Apps deployment with Docker
Completely anonymous and zero-trace chat flow