HVAC Water Monitoring Elevators Access Control Fire Safety Waste Parking … Vendor IoT Backends … System Integrator 1 Building Management System … SI IoT Backends … System Integrator 2 G G D D D D D D D D D D D D D D D D D D D D D G G G G G G G G G G G G G G Complexity & attack surfaces grow to be unmanageable. Proprietary data is leaked. Security becomes untenable.