You can use a personal certificate to protect your identity over the Internet. A certificate is a statement guaranteeing the identity of a person or the security of a Web site. You can control the use of your own identity by having the private key that only you know on your own system. When used with mail programs, security certificates with private keys are also known as "digital IDs."
Internet Explorer uses two different types of certificates:
A security certificate, whether it is a personal certificate or a Web site certificate, associates an identity with a "public key." Only the owner knows the corresponding "private key" that allows the owner to "decrypt" or make a "digital signature." When you send your certificate to other people, you are actually giving them your public key, so they can send you encrypted information which only you can decrypt and read with your private key.
The digital signature component of a security certificate is your electronic identity card. The digital signature tells the recipient that the information actually came from you and has not been forged or tampered with.
Before you can start sending encrypted or digitally signed information, you must obtain a certificate and set up Internet Explorer to use it. When you visit a secure Web site (one that starts with "https"), the site automatically sends you their certificate.
Security certificates are issued by independent certification authorities. There are different classes of security certificates, each one providing a different level of credibility. You can obtain your personal security certificate from certification authorities.