What aspect does hybrid identity rely on for user authentication?

Hybrid identity primarily relies on Active Directory Domain Services (AD DS) synchronization for user authentication. In a hybrid identity scenario, organizations typically have an on-premises Active Directory and use cloud services, like Microsoft 365 or Azure AD. The synchronization allows these organizations to maintain a consistent identity across both environments.

When users authenticate, the synchronized information from AD DS is used to facilitate access to various resources in the cloud. This integration enables users to utilize their existing credentials, minimizing the need for users to manage separate sets of credentials for on-premises and cloud-based applications.

While other options such as Multi-Factor Authentication, external identity providers, and Public Key Infrastructure may enhance security and identity management, they do not form the foundational aspect that hybrid identity relies upon for establishing user authentication. Instead, those elements serve as supplemental features or alternative methods for increasing security or managing identities in different contexts.