A digital certificate is provided to a customer having an electronic account linked to the customer's physical address. Using the digital certificate, the customer performs electronic transactions with a third party. A proofing workstation receives a request from a third party to validate the digital certificate. The proofing workstation communicates with a proofing server that maintains a list of valid certificates and a list of revoked certificates. The proofing server sends a response to the proofing workstation, where it is received by the third party.