This chapter provided an introduction to PKI and then progressed into detailed configuration and enrollment topics. To use digital certificates for authentication, you must first enroll with a CA and obtain and install a CA certificate on the Cisco ASA. Next, you must enroll and install an identity certificate from the same CA. This chapter showed how to enroll and install digital certificates on the Cisco ASA via SCEP or manually with the cut-and-paste method. It also provided detailed configuration steps for site-to-site and remote-access VPNs using digital certificates. Several troubleshooting tips and techniques were included at the end of the chapter.