What does a digital certificate primarily certify?

A digital certificate primarily certifies the identity of the owner of a public key. This certificate acts as a binding between the public key and the identity of its owner, typically verified by a trusted third party known as a Certificate Authority (CA). When a digital certificate is issued, it contains essential information such as the owner's name, the associated public key, the expiration date of the certificate, and the digital signature of the CA that verifies its authenticity. This ensures that when someone receives a public key embedded within a digital certificate, they can trust that the key indeed belongs to the individual or entity it claims to represent.

The other options do not reflect the primary function of a digital certificate. The strength of a password pertains to its complexity and resistance to guessing, while network security protocols relate to the frameworks that govern secure communications over networks, and user access permissions determine what resources a user can access within a system. These aspects are important in the realm of cybersecurity but are not the primary focus of what a digital certificate certifies.