Apparatus, method and computer program for managing digital certificates

In a digital certificate management system, a client/server system is connected to a digital certificate management apparatus (10) capable of communicating with clients (40) and servers (30). Mutual authentication is performed between the clients (40) and the servers (30) by using digital certificates and communications are performed over a communication channel established based on mutual authentication. The digital certificate management apparatus (10) includes a certification key update part updating a server certification key used for mutual authentication and stored in each of the clients (40) that become communication parties of one of the servers (30). The certification key updating part includes a key obtaining part, a certificate obtaining part, and first and second transmission parts. The second transmission part performs an operation of transmitting the new server certificate to each of the servers (30) after there are responses, indicating that the new server certification key is received, from all of the clients (40) that become communication parties of the server (30).