What is the primary function of a user certificate?

The primary function of a user certificate is to map a user to digital rights and access. User certificates serve as a means of identifying individuals within a digital framework, whereas they also define the permissions and access levels those individuals have within a system or network. This is crucial in environments where secure access to resources is needed; by associating the user with specific rights through their certificate, systems can ensure that only authorized users can perform certain actions or access sensitive information.

User certificates are often part of a Public Key Infrastructure (PKI) system, which enables the distribution of digital certificates to ensure secure communications. While encrypting internet traffic and verifying the identity of machines are also important security functions, these tasks are generally accomplished through other types of certificates or mechanisms, such as transport layer security (TLS) certificates or machine identity certificates. Similarly, revoking invalid certificates is a necessary maintenance function within PKI but not the direct role of user certificates themselves.