RadioLink Subsystem

RadioLink is the encrypted link layer used by the Nucleo-F439 LoRa weather station project.

Architecture

SX1262 Driver ↓ RadioLink

• framing
• encryption
• authentication
• replay protection
• persistence ↓ radioApp

Wire Protocol Version

Current wire format: Wire v3

Cryptography

Confidentiality: AES-128 CTR

Integrity / authenticity: AES-CMAC-128

Replay Protection

Key = (nodeId, sessionSeqId, msgCounter)

TX node persists counters using SPI FRAM. RX node keeps replay state in RAM.

Additional Documentation

• Wire v3 RX Processing Pipeline
• Wire v3 TX Processing Pipeline
• RadioLink Security Model
• Wire v3 Frame Format
• Protocol Verification and QA Harness