CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of International Application No. PCT/KR2012/000258, filed Jan. 11, 2012, which claims the priority to and benefit of Korean Patent Application No. 10-2011-0020924, filed on Mar. 9, 2011 in Korea. The disclosures of the above-listed applications are hereby incorporated by reference herein in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a cloud storage system, a device and method for performing a data encryption processing in the cloud storage system. 
     BACKGROUND ART 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. Generally, in order to use an information technology (IT) environment, a function is implemented by integrating elements such as a server, a storage, software, a solution, a line, etc., and solutions, such as a website, mail ERP, CRM, etc., are developed. The inventor(s) has experienced that in such development, the introduction of software and the integration and customizing of systems are needed, and thus, it is required to study separate technology. The inventor(s) has noted that cloud computing technology has been recently developed in which an IT environment is constructed to enable the use of a service even without professionalism of separated technology and is usable. 
     Such cloud computing can be largely categorized into three fields: namely, (i) Software as a Service (SaaS) that provides a software application service as a service; (ii) Platform as a Service (PaaS) that provides a standardized platform as a service; and (iii) Infrastructure as a Service (IaaS) that provides an infrastructure, such as a storage, a network, etc., as a service. 
     A cloud storage system, one of the cloud computing technology, virtually makes different users&#39; data appear to be stored in separate spaces, but actually stores the data in the same storage space physically. 
     The cloud storage system does not encrypt and store data itself when storing the data but encrypts and stores the data in transmitting the data. 
     On the other hand, the inventor(s) has noted that a function of encrypting and storing a document is necessarily needed for storing a document (for example, documents of companies) requiring security in a cloud storage. 
     However, the inventor(s) has experienced that the cloud storage system that provides a storage service for large-scale data causes overhead of calculation necessary for encrypting and decrypting data when desiring to directly support an encryption function, and thus, the use of many resources is needed. 
     SUMMARY 
     In accordance with some embodiments of the present disclosure, a data encryption processing device comprises a priority manager and an encryption requester. The priority manager is configured to manage a priority to encrypt data of each of a plurality of cloud storage modules based on information regarding whether to support encryption processing to said each of the plurality of the cloud storage modules; and an encryption requester configured to select at least one cloud storage module among the plurality of the cloud storage modules based on the priorities managed by the priority manager, and transfer data to the selected at least one cloud storage module to request the selected at least one cloud storage module to perform encryption of the data, in response to a data encryption request. 
     In accordance with some embodiments of the present disclosure, a data encryption processing device is configured to set a priority to encrypt data of each of a plurality of cloud storage modules to store the priority in a memory, based on information regarding whether to support encryption processing to each of the plurality of the cloud storage modules; select at least one cloud storage module based on the priority stored in the memory, when requesting encryption of the data; and transmit the data to the selected at least one cloud storage module to request the selected at least one cloud storage module to perform encryption of the data. 
     In accordance with some embodiments of the present disclosure, a cloud storage system for data encryption processing comprises a data encryption processing device; and a plurality of cloud storage modules. The plurality of cloud storage modules is configured to store and manage data and connected with the data encryption processing device over a communication network, wherein each of the plurality of cloud storage modules includes a cloud storage and a controller. The cloud storage configured to store the encrypted data and resource information. And the controller configured to control the cloud storage, provide the resource information to the data encryption processing device, encrypt data when receiving a request for data encryption from the data encryption processing device, store the encrypted data in the cloud storage, and decrypt the encrypted data stored in the cloud storage and supply the decrypted data to at least one different cloud storage module among the plurality of the cloud storage modules when receiving a request for the decrypted data from the data encryption processing device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of a cloud storage system in accordance with at least one embodiment of the present disclosure; and 
         FIG. 2  is a flowchart of a method of encrypting data in the cloud storage system in accordance with at least one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a block diagram of a cloud storage system in accordance with at least one embodiment of the present disclosure. The cloud storage system includes a plurality of cloud storage modules  100 , and a data encryption processing device  170  that are connected to the plurality of cloud storage modules  100  over a communication network  150 . 
     Each of the cloud storage modules  100  includes a cloud storage  110  (for example, a hard disc, a memory, or the like) that provides a storage service for large-scale data to a company or an individual, and a controller  120  that is implemented as a central processing unit (CPU) for controlling the cloud storage  110 . The cloud storage module  100  encrypts data according to a data encryption request from the data encryption processing device  170 , and stores the encrypted data in the cloud storage  110 . Each of the cloud storage modules  100  includes a communication interface (not show) also can communicate to each other and the data encryption processing device  170  over communication network  150  including, but not limited to, cellular, Wi-Fi, LAN, WAN, CDMA, WCDMA, GSM, LTE and EPC networks, and cloud computing networks. Alternatively, the communication interface can be installed as a communication module in a part of, or independently from, the controller  120 . 
     According to at least one embodiment of the present disclosure, the plurality of cloud storage modules  100  are largely categorized into two types, namely, a type of cloud storage module in which the controller  120  supports (or performs) processing of data encryption, and a type of cloud storage module in which the controller  120  cannot support processing of data encryption. Here, as an example of the controller  120  that supports processing of data encryption, there may be a CPU having an advanced encryption standard new instruction (AES-NI) function. 
     Each cloud storage module  100  provides its own resource information to the data encryption processing device  170 . Here, the resource information may include resource information regarding the controller  120  and cloud storage  110 . Also, the controller  120  of each cloud storage module  100  may encrypt data, when encryption of the data is requested from the data encryption processing device  170 , store the encrypted data in the cloud storage  110 . When receiving request of supplying a decrypted data from the data encryption processing device  170 , the controller  120  of each cloud storage module  100  decrypts the encrypted data stored in the cloud storage  110 , and supply the decrypted data to at least one different cloud storage module among the plurality of cloud storage modules  100 . 
     The data encryption processing device  170  requests data encryption from at least one cloud storage module selected among the plurality of cloud storage modules  100 , and allows the selected cloud storage module  100  to store encrypted data or to supply encrypted data stored in the selected cloud storage module  100  to the at least one different cloud storage module according to a request of the at least one different cloud storage module among the plurality of cloud storage modules  100 . 
     In at least one embodiment of the present disclosure, although the data encryption processing device  170  is connected to the plurality of cloud storage modules  100  over the communication network  150 , the above-described function of the data encryption processing device  170  may be embodied in, for example, a computer program or hardware module where the program is installed, and be implemented in each cloud storage module  100 . 
     As illustrated in  FIG. 1 , the data encryption processing device  170  includes a priority manager  172 , an encryption requester  174 , a resource manager  176 , and a memory  178 . 
     The priority manager  172  separately manages at least one of the plurality of cloud storage modules  100  in such a manner of checking (or identifying or distinguishing) which could storage module(s) is enabling the support of encryption processing or disenabling the support of encryption processing, according to resource information regarding each of the plurality of cloud storage modules  100  connected thereto over the communication network  150 . Also, as described later, the priority manager  172  grades an encryption priority of each cloud storage module  100  enabling the support of encryption processing, based on a count value of the number of encryption requests for and resource information regarding each of the plurality of cloud storage modules  100 . The graded priority is stored in the memory  178 . In the priority manager  172 , a cloud storage module enabling the support of encryption processing is higher in grading an encryption priority than a cloud storage module disenabling the support of encryption processing. 
     When a company or an individual requests encryption of certain data, in response to the encryption request, the encryption requester  174  transmits the requested certain data to a certain cloud storage module  100  selected according to priorities of each of the cloud storage modules  100 , and then requests the selected certain cloud storage module  100  to perform encryption for the transmitted certain data. When requesting the selected certain cloud storage module  100  to perform the encryption for the transmitted certain data, the encryption requester  174  counts up the number of requests for encryption that is being currently performed in the certain cloud storage module  100  selected for encrypting the certain data. Further, when the selected cloud storage module ends performing encryption for the certain data, the encryption requester  174  counts down the number of encryption requests. In other words, the encryption requester  174  selects a cloud storage module to perform data encryption among the plurality of graded cloud storage modules  100 , based on a count value of the number of encryption requests and whether to support encryption processing to each of the cloud storage modules  100 . In more detail, the encryption requester  174  selects at least one cloud storage module among the plurality of the cloud storage modules  100 , which can be enabling the support of encryption processing, according to priorities graded in descending order or ascending order of count value of the number of encryption requests, and requests data encryption from the selected at least one cloud storage module. 
     The priority manager  172  changes (or updates) a priority of each of cloud storage modules  100  according to a count value of the number of encryption requests being changed. Specifically, when requesting data encryption and when ending the data encryption, the priority manager  172  recognizes the change of the count value of the number of encryption requests to change the priority of each of the cloud storage modules  100 . 
     For example, a certain cloud storage module selected by the encryption requester  174  may complete data encryption, and then, the certain cloud storage module may store the encrypted data. Alternatively a different cloud storage module of the plurality of the cloud storage modules  100  may store the encrypted data in its own cloud storage. 
     The resource manager  176  manages available resource information, supplied from each of the cloud storage modules  100 , regarding each of the cloud storage modules  100 . Here, the resource information includes a size of encrypted data of each cloud storage module  100 , and specifications of a controller  120  and a cloud storage  110  of each cloud storage module  100 . 
     As described above, unlike a cloud storage module to perform encryption being selected according to whether to support encryption processing and a count value of the number of encryption requests, as an alternative scheme, the priority manager  172  may change the priorities of the plurality of the cloud storage modules  100  based on a changed (or updated) count value of the number of encryption requests and resource information supplied from the resource manager  176 . Meanwhile, the data encryption processing device  170  includes a communication interface (not show) which can communicate to at least one of the plurality of the cloud storage modules  100  over communication network  150  including, but not limited to, cellular, Wi-Fi, LAN, WAN, CDMA, WCDMA, GSM, LTE and EPC networks, and cloud computing networks. Alternatively, the communication interface can be installed as a communication module in a part of, or independently from, one component of the data encryption processing device  170 . Other components of the data encryption processing device  170 , such as the priority manager  172 , the encryption requester  174  and the resource manager  176  are implemented by one or more processors and/or application-specific integrated circuits (ASICs). 
       FIG. 2  is a flowchart of a method of encrypting data in the cloud storage system in accordance with at least one embodiment of the present disclosure. 
     First, as illustrated in  FIG. 2 , the priority manager  172  receives information regarding whether to support encryption processing from each of the plurality of the cloud storage modules  100  connected thereto over the communication network  150 , and grades a priority of each of the plurality of the cloud storage modules  100 , based on the information regarding whether to support encryption processing and a count value of the number of encryption requests for each of the plurality of the cloud storage modules  100 . The graded priorities are stored in the memory  178  in operation S 200 . 
     Subsequently, when an arbitrary company or a user requests encryption of data at a time when the data is stored in operation S 202 , the encryption requester  174  selects at least one cloud storage module among the plurality of the cloud storage modules  100  to perform data encryption according to the priorities of the respective cloud storage modules  100  stored in the memory  178  in operation S 204 . 
     Then, in operation S 206 , the encryption requester  174  transmits data to the selected at least one cloud storage module to perform, by the selected at least one cloud storage module, encryption of the data. Therefore, the selected at least one cloud storage module encrypts the data using its own resource information, and stores the encrypted data in a cloud storage of the selected at least one cloud storage module. 
     After the encryption request, in operation S 208 , the encryption requester  174  increases a count value of the number of encryption requests for the selected at least one cloud storage module  100 , and supplies (or transmits) the increased count value to the priority manager  172 . Thus, the priority manager  172  updates a priority of each cloud storage module  100  having a priority right to encrypt in real time, based on the increased count value. 
     Subsequently, in operation S 210 , the encryption requester  174  determines whether encryption is ended in the selected at least one cloud storage module. When a message indicating “end of encryption” is received from the selected at least one cloud storage module, the encryption requester  174  proceeds to operation S 212 . In operation S 212 , the encryption requester  174  decreases a count value of the number of encryption requests for the selected at least one cloud storage module, and supplies (or transmits) the decreased count value to the priority manager  172 . Thus, the priority manager  172  updates a priority of each cloud storage module  100  having a priority right to encrypt according to the decreased count value. 
     According to the above-described embodiments of the present disclosure, a cloud storage module connected to the data encryption processing device over the communication network directly performs an encryption processing operation that affects calculation overhead, and thus can reduce the overall calculation overhead of the cloud storage system and moreover quickly process calculation of data encryption. 
     Moreover, in at least one embodiment of the present disclosure, it has been described above as an example that a cloud storage module  100  is selected based on whether to support encryption processing and a count value of the number of encryption requests, and the selected cloud storage module  100  encrypts data. However, as another example, a cloud storage module  100  to encrypt data may be selected based on resource information, whether to support encryption processing, and a count value. For example, the priority manager  172  may set a priority of each cloud storage module  100  based on resource information regarding the controller and the memory, information regarding whether to support encryption processing, and a count value of the number of encryption requests, which are supplied from the plurality of cloud storage modules  100 . 
     The above-described encryption processing device  170  according to the at least one embodiment of the present disclosure may be implemented in the cloud storage module  100 . Also, both or either of the encryption processing device  170  and each of the plurality of cloud storage modules  100  has been described above, for example, as an independent device including a processor that autonomously processes information and a memory, which is merely exemplified for a description on the embodiments of the present disclosure. The present disclosure is not limited thereto. For example, the present disclosure may include a cloud computing environment in which the above-described information is permanently stored in a virtualization device (or server) on a network, and temporarily stored in the encryption processing device  170  and the plurality of cloud storage modules  100 . That is, it should be noted that the above-described information is stored in the virtualization device on the network, and a user equipment including various multimedia functions may use the above-described information anywhere at any time. 
     The present disclosure may be used as technology that encrypts data and stores the encrypted data in a storage in a cloud computing environment. Moreover, the present disclosure may be used as technology that can enhance processing performance in encrypting data in a cloud environment, and moreover efficiently manage resources in the cloud environment. The some embodiments of the present disclosure directly encrypts and stores data using resources of a plurality of cloud storage modules, and can thereby reduce calculation overhead caused by data encryption, thus enhancing security of data such as a secret document. Moreover, the present disclosure grades priorities of the respective cloud storage modules based on whether to support encryption processing by a central processing units of each of the cloud storage modules, and selects a specific cloud storage module based on the graded priorities to allow the selected cloud storage module to encrypt data, thus enhancing a processing speed of data encryption. 
     Some embodiments as described above may be implemented in the form of one or more program commands that can be read and executed by a variety of computer systems and be recorded in any non-transitory, computer-readable recording medium. The computer-readable recording medium may include a program command, a data file, a data structure, etc. alone or in combination. The program commands written to the medium are designed or configured especially for the at least one embodiment, or known to those skilled in computer software. Examples of the computer-readable recording medium include magnetic media such as a hard disk, a floppy disk, and a magnetic tape, optical media such as a CD-ROM and a DVD, magneto-optical media such as an optical disk, and a hardware device configured especially to store and execute a program, such as a ROM, a RAM, and a flash memory. Examples of a program command include a premium language code executable by a computer using an interpreter as well as a machine language code made by a compiler. The hardware device may be configured to operate as one or more software modules to implement one or more embodiments of the present disclosure. In some embodiments, one or more of the processes or functionality described herein is/are performed by specifically configured hardware (e.g., by one or more application specific integrated circuits or ASIC(s)). Some embodiments incorporate more than one of the described processes in a single ASIC. In some embodiments, one or more of the processes or functionality described herein is/are performed by at least one processor which is programmed for performing such processes or functionality. 
     Although the various embodiments of the present disclosure have been described, it is understood that the present disclosure should not be limited to these embodiments but various changes and modifications can be made by one ordinarily skilled in the art within the subject matter, the spirit and scope of the present disclosure as hereinafter claimed. Specific terms used in this disclosure and drawings are used for illustrative purposes and not to be considered as limitations of the present disclosure.
A cloud storage system includes a plurality of cloud storage modules for storing and managing data and a data encryption processing device. The data encryption processing device includes a priority manager for managing priorities on encrypting data of a plurality of cloud storage modules by using information on whether encryption processing for each of the plurality of the cloud storage modules is supported; and an encryption requester for selecting at least one cloud storage module on the basis of the priorities managed by the priority manager when receiving request of a data encryption, and performing, by the selected at least one cloud storage module, encryption after delivering the data to the selected cloud storage module.