What type of certificate is directly chained to the root certificate in Group Enrollment?

In the context of Group Enrollment in IoT, the correct answer refers to a leaf certificate. This is a type of certificate that is directly issued to an end entity, such as a device in an IoT context, and it is indeed chained to a root certificate through one or more intermediate certificates.

A leaf certificate typically contains the public key of the device and is used for establishing secure communications. This establishes trust as it validates that the device communicating with the IoT solution is recognized as secure under the root certificate authority.

If we consider the other options, a self-signed certificate is created and signed by the entity itself rather than a recognized certificate authority, which does not provide the external validation needed for securely connecting devices. An intermediate certificate serves as a bridge between the root and the leaf certificate, but it is not the end entity certificate itself. A verification certificate is not a standard term used in this context to describe the certificates involved in group enrollments.

Understanding the role and hierarchy of certificates, particularly the function of the leaf certificate, is essential for establishing secure device communication in Azure IoT solutions.