Patent 7526642 was granted and assigned to Nokia on April, 2009 by the United States Patent and Trademark Office.
In order to enable a home network operator to also control the issuing of certificates to a roaming subscriber, first information indicating whether or not it is allowed to issue a certificate to the subscriber is maintained in the subscription information. The first information is checked in response to a subscriber's certificate request received from the subscriber and the certificate is generated and delivered to the subscriber only if certificate issuance is allowed.