A company that provides cloud-based storage services allows user authentication using third- party social network credentials. Which of the following should be implemented to accomplish this task?

Multifactor authentication requires users to verify their identity using more than one method, and integrating a third-party social network credential adds an external verification factor to the authentication flow. The social network independently authenticates the user through its own credentials before granting access to the cloud service, constituting an additional factor beyond a single shared secret. This approach increases security by requiring valid authentication from a trusted third-party identity source that the user already possesses.

A VPN encrypts network traffic between endpoints but does not provide an identity verification mechanism for authenticating users via external third-party credentials.

Federation describes trust relationships between separate organizational identity domains - typically enterprise SAML or ADFS configurations - rather than consumer-facing social network credential authentication.

Domain trusts are a Windows Active Directory mechanism for cross-domain authentication within enterprise environments and are not applicable to social network credential integration in cloud storage services.