HTTPS (Hypertext Transfer Protocol Secure) is the most suitable protocol for secure communication between clients and servers. HTTPS uses TLS to encrypt data in transit, ensuring confidentiality, integrity, and authentication. This prevents attackers from eavesdropping, tampering, or impersonating servers.
HTTP and FTP transmit data in clear text, making them vulnerable to interception. SMTP is used for email delivery, not client-server web communication. Modern security standards mandate HTTPS for all production web applications.