The disclosure relates to the management of PKI digital certificates, including certificate discovery, installation, verification and replacement for endpoints over an insecure network. A database of certificates may be maintained through discovery, replacement and other activities. Certificate discovery identifies certificates and associated information including network locations, methods of access, applications of use and non-use, and may produce logs and reports. Automated requests to certificate authorities for new certificates, renewals or certificate signing requests may precede the installation of issued certificates to servers using installation scripts directed to a particular application or product, which may provide notification or require approval or intervention. An administrator may be notified of expiring certificates, using a database or scanning or server agents. Interaction with certificate authorities may be by an abstractor providing a common intefface for issuing signing requests to disparate certificate authorities. Digital certificate management may also be applied to network-connecting client devices.