Chapter 3 Authentication for FortiOS 5.0 : Certificate-based authentication : Configuring certificate-based authentication : Authenticating administrators with security certificates
  
Authenticating administrators with security certificates
You can install a certificate on the management computer to support strong authentication for administrators. When a personal certificate is installed on the management computer, the FortiGate unit processes the certificate after the administrator supplies a username and password.
To enable strong administrative authentication:
Obtain a signed personal certificate for the administrator from a CA and load the signed personal certificate into the web browser on the management computer according to the browser documentation.
Install the root certificate and the CRL from the issuing CA on the FortiGate unit (see “Installing a CA root certificate and CRL to authenticate remote clients”).
Create a PKI user account for the administrator.
Add the PKI user account to a firewall user group dedicated to PKI-authenticated administrators.
In the administrator account configuration, select PKI as the account Type and select the User Group to which the administrator belongs.