What role does a Root CA play in a PKI system?

In a Public Key Infrastructure (PKI) system, a Root Certificate Authority (Root CA) serves a critical function in establishing a chain of trust for digital certificates. Its primary role is to create and sign certificates for Intermediate CAs. This ensures that the Intermediate CAs can then issue certificates to end users or systems, effectively delegating the trust relationship initiated by the Root CA.

By signing the certificates of Intermediate CAs, the Root CA provides assurance that these Intermediate CAs are trustworthy and that any certificates they issue can be trusted as well. This hierarchical model enhances security by allowing for easier management of numerous certificates while maintaining a solid foundation of trust at the root level. The Root CA is typically kept offline or in a highly secure environment to prevent compromise, as its integrity is vital to the overall security of the PKI system.

This understanding emphasizes the importance of the Root CA in maintaining the integrity of the certificate issuing process and the trustworthiness of the entire PKI infrastructure.