Real-Time Medical Device Telemetry Webhook Handler

Create a bash script that sets up a secure webhook listener for IoT medical devices, capturing real-time telemetry data from continuous glucose monitors, wearable heart rate sensors, and remote patient monitoring equipment. The script must: 1) Validate incoming webhook payloads using cryptographic signatures, 2) Parse JSON telemetry data, 3) Store normalized data in a time-series database, and 4) Trigger automated alerts for critical health metrics that exceed predefined thresholds. Implement robust error handling and ensure HIPAA-compliant data transmission.