End-to-end encrypted messaging system with multi-device identity, offline delivery, group messaging, local history and terminal TUI. Implemented X3DH session bootstrap, symmetric ratcheting, device challenge-response authentication, certificate-based identity binding, and at-rest encryption for client/server secrets.
Designed custom TCP and UDP protocols with FEC, fragmentation, ordered delivery, and exponential backoff retransmission. Simulated a mothership-rover mission architecture and built a real-time dashboard validated in CORE under packet loss and latency.
Built a Linux document indexing service around FIFO-based client-server communication with persistent indexing for stateful retrieval. Added an LRU cache and parallel keyword search, with process cleanup and concurrency control for safe multi-document execution.
Conducted a complete software development lifecycle from requirements through architecture, implementation, testing, and documentation, using structured LLM assistance. Applied a three-pillar methodology of upfront planning, strict modular decomposition, and mandatory human review on every LLM output, explicitly distinguishing the approach from unstructured vibe coding.
Strengthened two Java applications with unit tests, property-based tests, coverage analysis, mutation testing, and automated test generation. Automated the full quality pipeline with Maven/Make, expanding the suite to 444 tests and achieving PIT mutation scores of 76% and 85% across the two projects.