What is a client certificate?
Client certificates contain information that identifies the user, as well as information about the organization that issued the certificate. For example, a standard X.509 certificate contains at least the following: • Version • Serial number • Signature algorithm ID • Issuer name • Validity period • Subject (user) name • Subject public key information • Signature on the fields just listed Figure 9.14 shows an example of a client authentication certificate in Microsoft® Internet Explorer 5: Figure 9.14 A Client Authentication Certificate A user obtains a client certificate from a trusted third-party organization such as VeriSign ( http://www.verisign.com) or Thawte Consulting ( http://www.verisign.com http://www.thawte.com). These organizations are usually referred to as certification authorities or CAs. If you have Microsoft® Windows® 2000 Certificate Services installed, your site can issue its own certificates to users on the intranet or to business partners.
