HTTPS (Hypertext Transfer Protocol Secure) has evolved into the de facto standard for secure Web browsing. Through the certificate-based authentication protocol, Web services and Internet users first authenticate one another ("shake hands") using a TLS/SSL certificate, encrypt Web communications end-to-end, and show a padlock in the browser to signal that a communication is secure. In recent years, HTTPS has become an essential technology to protect social, political, and economic activities online.