A certificate is a statement guaranteeing the identity of a person or the security of a Web site. Internet Explorer uses two different types of certificates.
A personal certificate is a kind of guarantee that you are who you say you are. You specify information about yourself, such as your user name and password. This information is then stored in a certificate, which is used when you send personal information to a client authentication server that requires a certificate.
A Web-site certificate contains information that a specific Web site is secure and genuine. This ensures that no other Web site can assume the identity of the original secure site. Web site certificates are also dated when they are issued. When you try to open an organizationÆs Web site, Internet Explorer verifies the Internet address stored in the certificate and that the current date precedes the expiration date. If the information is not current and valid, Internet Explorer can display a warning.