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