Patent ID: 7386722

Claim:
A management system of a public key certificate comprising: a first certificate authority; a service provider which verifies validity of a presented public key certificate and, if the verification can correctly be made, provides a service; a second certificate authority on which said service provider relies; and a smart card, wherein said smart card comprises a storing unit and a certificate issuing unit, said storing unit stores; a first private key and a first public key making a pair together therewith which are necessary to issue a certificate to said second certificate authority, a first certificate issued for said first public key from said first certificate authority, a second private key and a second public key making a pair together therewith which are generated to receive a service from said service provider, and a second certificate which is issued for said second public key by said second certificate authority on which said service provider relies, said second certificate authority comprises: a storing unit which stores a third private key for generating the second certificate of said second public key for said smart card and a third certificate which is issued to a third public key making a pair together with said third private key; and a certificate generating unit which generates the second certificate for said second public key on the basis of an issuing request, and said certificate issuing unit of said smart card comprises a third certificate generating unit which issues the third certificate for said third public key stored in said second certificate authority by using said stored first private key on the basis of an issuing request for the certificate from said second certificate authority.