What is a digital certificate used for?

A digital certificate is primarily used to prove ownership of a public key and facilitate secure communication. It serves as a special electronic document that associates a public key with an entity—such as a person, organization, or device—essentially acting as a digital passport. When one party wants to communicate securely with another, the digital certificate enables them to verify the legitimacy of the public key they receive.

In secure communications, such as those that use SSL/TLS protocols, the digital certificate assures the parties that they are indeed communicating with the intended entity and not an imposter. This helps establish a secure connection by enabling encryption and ensuring the authenticity of the entities involved in the communication.

The other choices represent functions that are indeed related to cybersecurity but do not capture the primary purpose of a digital certificate. Storing user credentials for authentication pertains more to password management and secure storage rather than public key infrastructure. Encrypting data in transit is a process that can utilize a digital certificate but is not its primary purpose. Similarly, authenticating server-side applications might involve digital certificates, but the essence of what a digital certificate does revolves around key ownership and secure communication rather than specifically authenticating applications.