Week 2 — TLS Fundamentals for Embedded Devices
TLS is the backbone of secure IoT communication — but misuse is common.
1. What TLS Actually Provides
TLS ensures:
- Confidentiality
- Integrity
- Server authentication
- Optional client authentication
TLS does not fix:
- Weak credentials
- Poor certificate handling
- Broken trust models
2. TLS Handshake (Simplified)
The handshake establishes:
- Cryptographic algorithms
- Session keys
- Trust validation
In embedded systems, handshake cost matters:
- CPU usage
- RAM usage
- Latency
3. Certificates vs Pre-Shared Keys
Certificates
- Scalable
- Strong identity
- Higher memory footprint
Pre-Shared Keys (PSK)
- Lightweight
- Harder to rotate at scale
- Risky if reused
4. Common Embedded TLS Mistakes
❌ Skipping certificate validation
❌ Accepting any server certificate
❌ Reusing keys across devices
Week 2 Takeaway
TLS is secure only when identity verification is enforced.