The main function of a digital certificate is to provide a secure means of establishing the identity of entities over the internet. Digital certificates, issued by trusted entities known as Certificate Authorities (CAs), authenticate the identity of websites, individuals, or organizations during online transactions. They contain information such as the public key, the individual or organization’s details, and the CA's signature. Digital certificates are essential for enabling SSL/TLS encryption, ensuring that data transmitted over the internet remains confidential and secure.