摘要 |
The method is for securely expanding a storage capacity of an IC portable device's memory. For a given data object stored or to be stored in the memory of the IC portable device, a unique master certificate, used as a descriptor of the data object, is generated randomly. The master certificate is indexed in the memory of the portable device. A secondary certificate is derived from and is determinable only using the master certificate. The data object is stored with the secondary certificate on a data storage medium external to the portable device. The memory of the smart card is thus freed from the data object and only the IC portable device has key information to retrieve the data object stored on the data storage medium. |