Selectively limiting read access to a portable storage device

Abstract

In electronic equipment device 1, a limitation level on reading an access level to selectively control the ability to read data from a USB flash drive (storage device) 2 is set to a setting section by an access level setting unit 3 in advance. The USB flash drive 2 ascertains the setting at the setting section 3 access level when the USB flash drive is connected to the electronic equipment 1 and limits reading data based on the determined setting device. If the limitation access level does not match with the condition for permitting data read-out as determined in USB flash drive 2 permit the reading of data, the USB flash drive 2 prohibits the electronic equipment 1 device from reading out data from a memory 24 of the USB flash drive by removing an application of power from the external device to the memory. By executing the processing for limiting data read-out at the side of the USB flash drive 2, unauthorized leakage of data can easily be prevented.

What is claimed is: 
     
       1. An electronic equipment system, comprising;
 an electronic equipment device; and 
 a storage device configured to be connected to the electronic equipment which reads data from the storage device device and having a memory unit, 
 wherein the electronic equipment device includes
 aan access level setting section having set a limitationunit for setting and storing an access level on reading out data fromfor limiting read access to the memory unit of the storage device by the electronic device, wherein the access level setting unit sets the access level prior to connection of the storage device to the electronic device, and 
 
 the storage device includes
 a limitation storage section for storing one or more values of a limitation level for permitting reading data, 
 an ascertainment section for ascertaining the limitation access level determination circuit configured to determine the access level set at the by the access level setting section when unit responsive to connection of the storage device is connected to the electronic equipment, and a limitation section for limiting device, wherein the access level determination circuit selectively controls the reading of data in accordance with the limitation level ascertained by the ascertainment section and the one or more values stored by the limitation storage section from the memory unit in accordance with the determined access level by selectively connecting a source of electrical power to or removing the source of electrical power from at least the memory unit of the storage device. 
 
 
     
     
       2. The electronic equipment system according to  claim 1 ,
 wherein the limitation section access level determination circuit includes
 a permission section unit for permitting reading data if the limitation access level ascertained by the ascertainment section access level determination circuit is consistent with the one or more values, and 
 a prohibition section unit for prohibiting reading data if the limitation access level ascertained by the ascertainment section access level determination circuit is not consistent with the one or more values. 
 
 
     
     
       3. The electronic equipment system according to  claim 2 ,
 wherein the electronic equipment device further includes
 a first power supply section for supplying electric power to the storage device connected to the electronic equipment device, 
 the storage device further includes,
 a data output section for reading out data and outputting unit configured to read and output the data to the electronic equipment device, and 
 a second power supply section that is connected to the first power supply section when the storage device is connected to the electronic equipment device, for supplying electric power from the first power supply section to the data output section unit, 
 
 wherein
 the data output section unit is operated by electric power supplied from the second power supply section, and 
 the second power supply section switches between supplying and cutting of electric power to the data output section unit, 
 the permission section unit makes the second power supply section supply electric power to the data output section unit if the limitation level ascertained by the ascertainment section access level is consistent with the one or more values, thereby allowing the data output section to read out data, and 
 
 
 the prohibition section unit makes the second power supply section cut power to the data output section unit if the limitation level ascertained by the ascertainment section access level is not consistent with the one or more values, thereby not allowing the data output section unit to read out data. 
 
     
     
       4. The electronic equipment system according to  claim 1 , wherein the memory unit of the storage device further includes
 a plurality of data storage sections portions, 
 the limitation storage section access level determination circuit stores some values of a limitation level for permitting reading data from access levels for each of the plurality of data storage sections portions, and 
 the limitation section access level determination circuit includes 
 a permission section unit for permitting reading data from one or more specific data storage sections portions included in the plurality of data storage sections portions and for prohibiting reading data from other data storage sections portions which are not included in the one or more specific data storage sections portions among the plurality of data storage sections portions if the limitation level ascertained by the ascertainment section is consistent with the one or more values of the limitation level for permitting access levels permit reading data from the specific data storage sections portions, and 
 a prohibition section unit for prohibiting reading data from the plurality of data storage sections portions if the limitation level ascertained by the ascertainment section is not consistent with the one or more values of the limitation level for permitting access levels do not permit reading data from each of the plurality of data storage sections portions. 
 
     
     
       5. A storage device from which data is read out by an external equipment device, comprising:
 a non-volatile memory;  
 an ascertainment section access level determination unit for ascertaining a limitation an access level set at the external equipment device; 
 a limitationan access level storage sectionunit for storing one or more values of a limitation level for permitting reading dataranges of access levels; and 
 a limitation sectionan access restriction unit for limiting reading data in accordance with the limitation level ascertained by the ascertainment section and the one or more values stored by the limitation storage sectionread access to the non-volatile memory by the external device responsive to the access level ascertained by the access level determination unit and the one or more ranges of access levels stored by the access level storage unit by selectively applying or removing electrical power to or from the non-volatile memory. 
 
     
     
       6. An electronic system, comprising:
 an electronic device; and   a storage device configured to be removably connected to the electronic device, the storage device comprising a controller circuit and a non-volatile memory;   wherein the electronic device comprises an access level setting unit configured to establish an access level for the non-volatile memory of the storage device, the access level established by the access level setting unit set prior to connection of the storage device to the electronic device, and   wherein the storage device further comprises an access level determination circuit configured to selectively apply or remove electrical power to or from the controller circuit and the non-volatile memory responsive to the access level established by the access level setting unit.   
     
     
       7. A method comprising:
 coupling a storage device to an external device via an interface that facilitates a flow of electrical power from the external device to the storage device;   using the storage device to detect an access level, the access level established by the external device prior to the coupling step; and   activating a switching circuit of the storage device to prevent the flow of electrical power to a non-volatile memory of the storage device responsive to the access level detected by the storage device having a first selected value.   
     
     
       8. The method of claim 7, further comprising using the switching circuit of the storage device to allow the flow of electrical power to the non-volatile memory of the storage device responsive to the access level detected by the storage device having a different, second selected value. 
     
     
       9. The method of claim 7, wherein the activating step further comprises further preventing the flow of electrical power to a programmable processor of the storage device responsive to the access level detected by the storage device having the first selected value. 
     
     
       10. A portable storage device configured to be attached to and removed from a communication socket of an external device, the storage device comprising:
 a non-volatile memory comprising at least a first memory portion and a different, second memory portion;   an access level determination circuit configured to determine an access level, via a communication signal transmitted across the communication socket from the external device to the storage device; and   a switching circuit configured to respectively prohibit a flow of electrical power from the external device across the communication socket to at least a selected one of the first memory portion or the second memory portion responsive to a magnitude of the access level transmitted across the communication socket from the external device to the storage device to prevent a transfer of read data from the at least a selected one of the first memory portion or the second memory portion across the communication socket to the external device.   
     
     
       11. The storage device of claim 10, wherein the switching circuit is further configured to permit the flow of electrical power from the external device across the communication socket to a remaining one of the first memory portion or the second memory portion responsive to the magnitude of the access level transmitted across the communication socket from the external device to the storage device to facilitate a transfer of read data from the remaining one of the first memory portion or the second memory portion across the communication socket to the external device. 
     
     
       12. The storage device of claim 10, further comprising a top level controller comprising a programmable processor configured to transfer data from the non-volatile memory to the external device, wherein the switching circuit is further configured to prohibit the flow of electrical power from the external device across the communication socket to the top level controller responsive to the magnitude of the access level transmitted across the communication socket from the external device to the storage device. 
     
     
       13. The storage device of claim 10, wherein the access level determination circuit comprises an access level storage unit which stores a range of access levels, an access level determination unit which compares the access level transmitted from the external device to the range of access levels, and an access restriction unit which activates the switching circuit responsive to the comparison of the access level and the range of access levels. 
     
     
       14. The storage device of claim 10, wherein the non-volatile memory comprises flash memory. 
     
     
       15. The storage device of claim 14, wherein the communication socket comprises a USB (Universal Serial Bus) interface connection. 
     
     
       16. The storage device of claim 10, wherein the access level determination circuit receives the access level transmitted across the communication socket responsive to interconnection of the storage device to the external device. 
     
     
       17. A method comprising:
 ascertaining, by a storage device, an access level value set by an external device to which the storage device is coupled;   maintaining, at a local memory of the storage device, a range of access level values for permitting a reading of data from a non-volatile memory of the storage device; and   activating a switching circuit to forward electrical power supplied by the external device to the non-volatile memory responsive to the access level value falling within the range of access level values.   
     
     
       18. The method of claim 17, further comprising activating the switching circuit to prohibit the electrical power supplied by the external device from reaching the non-volatile memory responsive to the access level value falling outside the range of access level values. 
     
     
       19. The method of claim 17, wherein the storage device is coupled to the external device using a USB (Universal Serial Bus) interface, wherein the external device comprises an external device power supply that supplies the electric power to the storage device via the USB interface, and wherein the storage device comprises a limitation processor circuit and a DC/DC converter configured to receive the electric power from the external equipment power supply, the limitation processor circuit configured to selectively enable or disable the DC/DC converter in supplying the electric power to the non-volatile memory of the storage device responsive to whether the access level value set by the external device falls within the range of access level values maintained by the local memory of the storage device. 
     
     
       20. The method of claim 17, wherein the storage device is coupled to the external device using a USB (Universal Serial Bus) interface, wherein the external device comprises an external device power supply that supplies the electric power to the storage device via the USB interface, and wherein the storage device comprises a storage device controller, a limitation processor circuit and a field effect transistor (FET), the limitation processor circuit configured to enable or disable the application of the electrical power, via the FET, to the limitation processor circuit and the non-volatile memory responsive to whether the access level set by the external device falls within the range of access level values maintained by the local memory of the storage device. 
     
     
       21. The method of claim 17, wherein the non-volatile memory of the storage device is partitioned into a first portion and a different, second portion, wherein the range of access level values maintained by the local memory of the storage device is a first range associated with the first portion, wherein the local memory of the storage device further maintains a second range of access level values associated with the second portion, and wherein read access to the respective first and second portions of the non-volatile memory is controlled responsive to whether the access level value set by the external device falls within the first range or the second range.