Which CA model involves a root CA issuing certificates to several intermediate CAs, which in turn issue certificates to end users?

The hierarchical CA model is characterized by a structure where a root Certificate Authority (CA) issues certificates to one or more intermediate CAs. These intermediate CAs then have the authority to issue certificates to end users or entities. This tiered structure enhances security and scalability within a public key infrastructure (PKI), as it allows for a limited number of trusted root CAs to delegate the responsibility of certificate issuance to intermediate CAs.

By employing this model, organizations can create a more organized approach to managing certificates. It also simplifies the revocation and renewal processes; if a single intermediate CA is compromised, only the certificates issued by that intermediate CA need to be re-evaluated, rather than affecting the entire CA ecosystem. Additionally, the hierarchical model helps in establishing a clear chain of trust, which is crucial for the validation and authentication of digital certificates across networks.

This organizational structure is a fundamental concept in cybersecurity frameworks, allowing for robust management of digital identities and secure communications among users and systems.