Security Certificates (SSL):
Whenever your site will be transmitting information of a sensitive nature, you need to use a security certificate and SSL. All a certificate does is verify your identity on the Web. It's issued by a certificate authority whom you pay annually for the service.
SSL (Secure Sockets Layer) goes along with a security certificate. It's a technology used by web browsers to encrypt information as it's transferred from one location (i.e. the user's browser) to another (i.e. your website). When paired with a security certificate, SSL shows your website users that you care about the sensitivity of their information. The browser will display a lock icon when a valid certificate is in use.