To ensure secure communication over the public internet, JayP needs to address authentication, confidentiality, and integrity concerns. Digital certificates play a vital role in solving these issues. They verify the identity of websites like YouTube and prevent man-in-the-middle attacks by confirming the source of the public key. Certificate Authorities (CAs) sign digital certificates, creating a chain of trust. Operating systems include trusted root CAs, and websites obtain intermediate certificates from CAs. The browser verifies certificates' authenticity through hashing and decryption, ensuring secure connections. Three types of TLS certificates are explained: Single Domain (for one specific domain), Wildcard (for main domain and subdomains), and Multi-Domain (SAN, for multiple unrelated domains in one certificate).