SSL certificates are data files that enable websites to use HTTPS, which is more secure than HTTP. They contain information that verifies the certificate and associates it with the domain it’s designed to protect, including the website’s public key, identity, domain name, certificate authority, and issuance and expiration dates. When a device tries to communicate with the website’s origin server, it references the SSL certificate to obtain the public key and verify the server’s identity. The private key is kept secret and secure.