What is the purpose of a digital certificate?

The purpose of a digital certificate is to prove ownership of a public key used in secure communications. Digital certificates play a critical role in establishing trust on the internet by enabling secure exchanges of information. When a digital certificate is issued by a trusted Certificate Authority (CA), it contains the public key, along with related information such as the identity of the owner, the CA’s digital signature, and other relevant details.

In secure communications like HTTPS, the digital certificate allows clients to verify that the public key they are using belongs to the entity it claims to represent, ensuring that the communication is encrypted and can only be read by the intended recipient. This helps prevent impersonation and man-in-the-middle attacks, as the authentic identity behind the public key is confirmed via the certificate.

Additionally, digital certificates are foundational to Public Key Infrastructure (PKI), which is used for secure transactions over the internet. The trust is anchored in the certificate's validity and the integrity provided by the CA's signature, making option B the correct choice.