HTTPS encrypts communication between browser and server using SSL/TLS protocols. TLS certificates are issued by Certificate Authorities (CAs) like Let's Encrypt. The TLS handshake involves client hello, server hello, certificate verification, and key exchange. Modern TLS 1.3 reduces handshake to one round trip. Obtain certificates through automated ACME protocol with Certbot. Configure your web server (Nginx, Apache) with certificate paths. Use strong cipher suites and disable outdated like SSLv3 and TLS 1.0. Implement HSTS (HTTP Strict Transport Security) to force HTTPS connections. Redirect all HTTP traffic to HTTPS permanently (301 redirect). Secure cookies with Secure, HttpOnly, and SameSite flags. Implement Content Security Policy to prevent XSS attacks. Use TLS for database connections and internal services. Monitor certificate expiration for renewal. Use certificate pinning for critical applications. Performance impact of HTTPS is minimal with modern hardware. HTTP/2 requires HTTPS for most browsers. Let's Encrypt provides free certificates with automated renewal. Regular security scanning with SSL Labs tests your configuration. HTTPS is no longer optional for any production website.