The Digital Certificates are issued by a certification authority (CA) and it contains the company name, a serial number, expiration dates, and a public key used for encrypting messages and digital signatures. The most widely used standard for digital certificates is X.509.

How to get a Digital Certificate. The individual or company wishing to encrypt information applies for a digital certificate from a Certificate Authority (CA). The CA issues an encrypted digital certificate containing the applicant's public key and a variety of other identification information. The CA makes its own public key readily available through the Internet.

The most common use of a digital certificate is to verify that a user a web site with is who he or she claims to be, and to provide some encription to the information. The recipient of some encrypted information uses the CA's public key to decode the digital certificate attached to the data, verifies it as issued by the CA and then obtains the sender's public key and identification information held within the certificate.