Practical Internet of Things Security - Second Edition

SSL pinning

This technique may apply more to IoT device developers that require their devices to communicate with an internet service (for example, for passing usage data or other information). In order to protect from the potential compromise of the trust infrastructure that provisions certificates, developers can pin the trusted server certificate directly into the IoT device trust store. The device can then check the server certificate explicitly against the certificate in the trust store when connecting to the server.

In essence, SSL pinning doesn't place full trust in the certificate's trust chain; it only trusts the server if the received server certificate is identical to the pinned (stored) certificate and the signature is valid. ...