IoT security: Using single certification across all devices?

Hi,

there are several reasons why to use a unique certificate per device. When you deploy for example 1 million devices and your certificate is being compromised you must exchange the certificate on all devices. When you deactivate the certificate all devices which share a certificate are affected.

If you use one unique device per certificate you only need to exchange the certificate on one device. You can also deactivate such a certificate without impacting other devices.

When you attach IoT policies to a certificate, all devices will share the same permissions when they share a certificate. This can prevent you from using IoT policies that conform to the least privilege principle.

The shadow service is unrelated to the certificate you use. Your device logic defines which shadow name in classic or named shadow you are going to use.

KR,

Philipp