Patent ID: 7062652

Claim:
A semiconductor memory card for use with an electronic device, said semiconductor memory card comprising: a rewritable nonvolatile memory having an authentication area and a non-authentication area; a device for holding information relating to an area size of said rewritable nonvolatile memory; a control unit for controlling accesses by the electronic device to the authentication area and the non-authentication area in said rewritable nonvolatile memory; and an area resizing unit for resizing the authentication area and the non- authentication area, wherein said area resizing unit resizes the authentication area and the non-authentication area based on the information relating to the area size of said rewritable nonvolatile memory after deleting all contents of said rewritable nonvolatile memory, wherein said control unit comprises: an authentication unit for performing an authentication process to check whether the electronic device has authority to access said semiconductor memory card, and affirmatively authenticating the electronic device when the electronic device has authority to access said semiconductor memory card; and an authentication area access control unit for permitting the electronic device to access the authentication area only when said authentication unit affirmatively authenticates the electronic device, and wherein the authentication area and the non-authentication area are provided by dividing a continuous area of a predetermined size in said rewritable nonvolatile memory into two parts.