How I Built Encrypted Bluetooth Team Sync in Flutter — AES-256-GCM, ECDH, CRDTs, Zero Servers

The author built Red Grid Link, an encrypted peer-to-peer team coordination app in Flutter that syncs positions over BLE and WiFi Direct without any servers. It addresses the need for off-grid position sharing for military, SAR, and outdoor teams by leveraging AES-256-GCM encryption, ECDH key exchange, and CRDTs for conflict resolution across Android and iOS transport layers.