Patent ID: 7496765

Claim:
A storage device that is carried by a user, and that sends and receives data to/from an information processing apparatus, comprising: a switch that enters a grant instruction not to conduct an access prevention processing for preventing an access to a portion or all of data recorded in the storage device, by being pressed by the user; an access prevention processing unit that conducts the access prevention processing in a case of detecting an isolation state where if the storage device is more than a preset distance from a predetermined instrument or a timeout state where a preset setting time or longer has passed since the storage device can no longer communicate with the predetermined instrument, and that does not conduct the access prevention processing in the case of detecting at least either the isolation state or the timeout state, on condition that a grant instruction is entered under the condition that the storage device can send/receive data to/from the predetermined instrument; and an access processing unit that grants the access to the data if the access prevention processing has not been conducted in the case of receiving an access request to the data from the information processing apparatus, and that that does not grant the access to the data if the access prevention processing has been conducted; wherein the access prevention processing unit encrypts the data recorded in the storage device, in the case of detecting at least either the isolation state or the timeout state; and wherein the access prevention processing unit comprises: a reading prevention unit for preventing reading the data in the case of detecting at least either the isolation state or the timeout state; an encrypting unit for encrypting the data where reading has been prevented; and a reading permitting unit for granting to read an encrypted data.