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Certificates

In OmniWOT, certificates are digital credentials used to securely identify and authenticate devices, users, or services. They form a critical part of Public Key Infrastructure (PKI), which ensures secure communication, device authentication, and data integrity in distributed IoT systems.

🔐 What Are Certificates in IoT?​

A certificate in the context of IoT is a digitally signed file (usually in X.509 format) that binds a public key to a device identity. It is issued by a trusted authority, such as a Certificate Authority (CA).

Each certificate typically contains:

  • The device’s public key
  • The device’s identity or unique ID (e.g., device EUI, serial number)
  • The issuer's identity (usually the CA)
  • Validity period (start and expiry)
  • A digital signature from the CA

🧩 Why Are Certificates Important in IoT?​

✅ Device Authentication​

  • Ensures only trusted devices can connect to the network (e.g., MQTT broker, LoRaWAN server).
  • Prevents unauthorized or rogue devices from joining the system.

✅ Secure Communication (TLS/DTLS)​

  • Certificates enable encryption protocols like TLS (HTTPS) and DTLS to secure data in transit.
  • Prevents eavesdropping and man-in-the-middle (MITM) attacks.

✅ Data Integrity​

  • Ensures the data hasn't been tampered with during transmission.

✅ Mutual Authentication​

  • Both client (device) and server validate each other’s identity using certificates.

📦 Where Are Certificates Used in IoT?​

  • Device-to-Cloud communication (e.g., over HTTPS or MQTT with TLS)
  • LoRaWAN Network Server connections
  • OTA (Over-the-Air) firmware updates
  • API access between services
  • Edge Gateway authentication
  • Secure provisioning and bootstrapping

📄 Common Types of Certificates​

TypePurpose
Device CertificateUnique to each device; used for authentication
Client CertificateUsed by the device/client in TLS/SSL communication
Server CertificateUsed by backend servers to prove their identity
Root CA CertificateTrusted authority used to sign other certificates
Intermediate CAMiddle layer CAs that sign device/server certs

🔄 Lifecycle of a Certificate​

  1. Generation: Device generates a key pair (private/public).
  2. CSR (Certificate Signing Request): Device sends CSR to CA.
  3. Issuance: CA issues and signs the certificate.
  4. Installation: Device installs the certificate and private key.
  5. Renewal/Rotation: Certificates are renewed before expiration.
  6. Revocation: If a device is compromised, its certificate is revoked.

🛠️ How Are Certificates Stored on IoT Devices?​

Depending on the device capability:

  • Secure Elements / TPMs: Hardware-based secure storage.
  • Secure Flash: Encrypted memory regions.
  • Software-only storage: Not ideal, but used on constrained devices.

🚀 Real-World Example​

AWS IoT Core requires each connected device to:

  • Present a unique certificate
  • Prove its identity using the private key
  • Communicate over TLS

Same applies to Azure IoT Hub, GCP IoT Core, ChirpStack, and OmniWOT (if supporting TLS-based connections).

🧠 TL;DR​

Certificates in IoT = Device Passports for Trust & Security

They’re essential for building a trusted, scalable, and secure IoT network—ensuring only authenticated, authorized devices can connect and communicate safely.