What is the purpose of a digital certificate in network security?

A digital certificate serves a crucial role in network security by verifying the identity of the sender. It acts as a digital form of identification issued by a trusted authority known as a Certificate Authority (CA). When a user or a server presents a digital certificate, it provides assurance that the entity is who they claim to be. This is fundamental in establishing secure communications over the internet, particularly in protocols like SSL/TLS, which are used to encrypt data and authenticate the parties in digital transactions.

In practice, when a client connects to a server, the server presents its digital certificate. The client checks the certificate against trusted CAs and validates it, ensuring that the communication is established with the legitimate entity rather than an impostor. This identity verification helps to prevent various types of attacks, such as man-in-the-middle attacks, and fosters trust in online interactions.

The other options do not accurately represent the primary function of a digital certificate in network security. They relate to other aspects of internet functionality that are not directly connected to the purpose of a digital certificate.