KR102564222B1 - Messenger service server that enables secure sharing of document files through messenger service and the operating method thereof - Google Patents

Abstract

The present invention can solve the problem of exposing document files shared through a messenger service to the outside by presenting a messenger service server and an operation method thereof enabling secure sharing of document files through a messenger service.

Description

Messenger service server enabling secure sharing of document files through messenger service and its operating method

The present invention relates to a messenger service server enabling secure sharing of document files through a messenger service and an operation method thereof.

Recently, as portable electronic terminals such as smart phones and tablet PCs are widely spread, various applications that can be used in these electronic terminals are appearing.

Among these applications, the use of applications for messenger services capable of chatting in real time is rapidly increasing.

A messenger service is a service that supports chatting parties to open a predetermined chat room and exchange various opinions in the chat room. In a recently emerging messenger service, chatting parties can share predetermined files in the chat room with each other. It provides a file sharing function.

A brief explanation of this file sharing function is as follows.

First, chatting parties may establish a predetermined chat room by accessing a session enabling chatting through their own electronic terminals, and then exchange chatting messages with each other in the chat room. At this time, when one of the chatting parties uploads a predetermined file onto the chat room through his or her electronic terminal, the people participating in the chat room use their electronic terminal to upload the file to the chat room. By downloading the file, file sharing can be performed.

The file sharing function in such a messenger service is one of the very useful functions in that it supports multiple people to easily share files. However, in the case of file sharing for certain important or secure documents through the messenger service in a company or institution that uses the messenger service for business purposes, the document file can be easily leaked to the outside. It is necessary to accompany certain security measures to prevent leaking to the outside.

Therefore, when a document file is shared through a messenger service, research related to an encryption technology is required to prevent the document file from being leaked to the outside.

The present invention solves the problem of exposing document files shared through a messenger service to the outside by presenting a messenger service server and an operating method thereof enabling secure sharing of document files through a messenger service.

A messenger service server enabling secure sharing of document files through a messenger service according to an embodiment of the present invention includes a member database in which preset member identification information for each of a plurality of members subscribed to the messenger service is stored; When a first document file is received from the electronic terminal of a first member who is any one of n (n is a natural number equal to or greater than 2) members participating in the chat room opened through the messenger service, a secure sharing request for the first document file is received. is received, encrypts the first document file with a preset encryption key, and then posts the encrypted first document file in the chat room so that the encrypted first document file can be downloaded through the chat room. A file encrypting unit that checks member identification information of each of the n members based on the member database, generates a first member list composed of member identification information of each of the n members, and then the first member A list designation unit for designating a list as a list of members having access to the first document file and storing the list in a list database; and the first document file encrypted from the electronic terminal of a second member who is any one of the n members. When a download request of is received, a file transmitter for transmitting the encrypted first document file to the electronic terminal of the second member, after the encrypted first document file is transmitted to the electronic terminal of the second member, When a request for decryption of the encrypted first document file is received from the electronic terminal of the second member, the encrypted first document file is received from the electronic terminal of the second member, and the first document file is displayed on the first member list. After confirming whether the member identification information of the second member exists, if it is confirmed that the member identification information of the second member exists in the first member list, the encrypted first document file is decrypted based on the encryption key. When the decryption unit and the decryption of the first document file are completed, the decrypted first document file is opened, a viewing image of the document according to the opening of the first document file is generated, and the viewing image is displayed as the first document file. 2 Includes a transmission unit that transmits to the member's electronic terminal.

In addition, in an operating method of a messenger service server enabling secure sharing of document files through a messenger service according to an embodiment of the present invention, preset member identification information for each of a plurality of members subscribed to the messenger service is stored. maintaining a member database, wherein a first document file is received from an electronic terminal of a first member among n (n is a natural number equal to or greater than 2) members participating in a chat room opened through the messenger service; When a secure sharing request for a first document file is received, the encrypted first document file is encrypted with a preset encryption key, and then the encrypted first document file is posted on the chat room, whereby the encrypted first document file is posted through the chat room. 1 Setting the download of a document file to be possible, checking member identification information of each of the n members based on the member database, and generating a first member list composed of member identification information of each of the n members and then designating the first member list as a member list having access to the first document file and storing the encrypted data in a list database from an electronic terminal of a second member who is one of the n members. When a download request for the first document file is received, transmitting the encrypted first document file to the electronic terminal of the second member, transmitting the encrypted first document file to the electronic terminal of the second member After that, when a request for decryption of the encrypted first document file is received from the electronic terminal of the second member, the encrypted first document file is received from the electronic terminal of the second member, and After checking whether the member identification information of the second member exists in the first member list, if it is confirmed that the member identification information of the second member exists in the first member list, the first document encrypted based on the encryption key. When the decryption of the file and the decryption of the first document file are completed, the decrypted first document file is opened, a viewing image of the document according to the opening of the first document file is created, and the viewing image is displayed. and transmitting to the electronic terminal of the second member.

The present invention can solve the problem of exposing document files shared through a messenger service to the outside by presenting a messenger service server and an operation method thereof enabling secure sharing of document files through a messenger service.

1 is a diagram showing the structure of a messenger service server enabling secure sharing of document files through a messenger service according to an embodiment of the present invention.
2 is a diagram for explaining the operation of a messenger service server enabling secure sharing of document files through a messenger service according to an embodiment of the present invention.
3 is a flowchart illustrating an operating method of a messenger service server enabling secure sharing of document files through a messenger service according to an embodiment of the present invention.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. This description is not intended to limit the present invention to specific embodiments, but should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. While describing each drawing, similar reference numerals have been used for similar components, and unless otherwise defined, all terms used in this specification, including technical or scientific terms, are common knowledge in the art to which the present invention belongs. has the same meaning as commonly understood by the person who has it.

In this document, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated. In addition, in various embodiments of the present invention, each component, functional block, or means may be composed of one or more sub-components, and the electrical, electronic, and mechanical functions performed by each component are electronic It may be implemented with various known elements or mechanical elements such as circuits, integrated circuits, ASICs (Application Specific Integrated Circuits), and may be implemented separately or two or more may be integrated into one.

On the other hand, the blocks of the accompanying block diagram or the steps of the flowchart are computer program instructions that perform designated functions by being loaded into a processor or memory of a device capable of data processing, such as a general-purpose computer, a special purpose computer, a portable notebook computer, and a network computer. can be interpreted as meaning Since these computer program instructions may be stored in a memory included in a computer device or in a computer readable memory, the functions described in blocks of a block diagram or steps of a flowchart are produced as a product containing instruction means for performing them. It could be. Further, each block or each step may represent a module, segment or portion of code that includes one or more executable instructions for executing specified logical function(s). Also, it should be noted that in some alternative embodiments, functions mentioned in blocks or steps may be executed out of a predetermined order. For example, two blocks or steps shown in succession may be performed substantially simultaneously or in reverse order, and in some cases, some blocks or steps may be omitted.

1 is a diagram showing the structure of a messenger service server enabling secure sharing of document files through a messenger service according to an embodiment of the present invention.

Referring to FIG. 1, a messenger service server 110 according to the present invention includes a member database 111, a file encryption unit 112, a list designation unit 113, a file transmission unit 114, a decryption unit 115, and A transmission unit 116 is included.

Preset member identification information for each of a plurality of members subscribed to the messenger service is stored in the member database 111 .

Here, the member identification information refers to unique information for identifying each member subscribed to the messenger service, such as a member ID, resident registration number, and mobile phone number.

The file encryption unit 112 receives a first document file from the electronic terminal 10 of a first member among n (n is a natural number equal to or greater than 2) members participating in a chat room opened through the messenger service, When a secure sharing request for the first document file is received, the first document file is encrypted with a preset encryption key, and then the encrypted first document file is posted on the chat room, so that the encrypted first document file is shared through the chat room. It is set to enable download of the first document file.

In this regard, as shown in FIG. 2 , the file encryption unit 112 is an electronic terminal 10 of a first member who is any one of n (n is a natural number equal to or greater than 2) members participating in a predetermined chat room 211 . When a first document file is received from ) and a secure sharing request for the first document file is received, after encrypting the first document file with a preset encryption key, as shown in reference numeral 212 of FIG. 2, the encrypted By posting the first document file on the chat room 211, it is possible to set the download of the encrypted first document file through the chat room 211 to be possible.

The list specifying unit 113 checks member identification information of each of the n members based on the member database 111 and generates a first member list composed of member identification information of each of the n members, The first member list is designated as a member list having access to the first document file and stored in a list database.

In relation to this, the list designator 113 may generate the first member list in the form of Table 1 below and store it in the list database.

Member identification information of the member having access to the first document file Member identification information 1 Member identification information 2 Member identification information 3 Member identification information 4 ...

At this time, according to one embodiment of the present invention, when the first member list is created, the list designator 113 generates a first hash value by applying the encrypted first document file as an input to a preset hash function. After doing so, the first hash value and the first member list may be stored in correspondence with each other on the list database.

In this way, after the encrypted first document file is posted in a downloadable state in the chat room and the first member list is stored on the list database by the list designator 113, one of the n members When the second member applies a command to download the encrypted first document file posted in the chat room to his or her electronic terminal 20, the electronic terminal 20 of the second member transmits a message service server When a download request of the encrypted first document file is received in 110, the file transmission unit 114 transmits the encrypted first document file to the electronic terminal 20 of the second member.

Then, the encrypted first document file may be downloaded to the electronic terminal 20 of the second member. In this way, when the encrypted first document file is downloaded to the electronic terminal 20 of the second member, the second member opens the encrypted first document file on the electronic terminal 20. A decryption command for the first document file may be applied. Then, the electronic terminal 20 may transmit a decryption request for decryption of the encrypted first document file to the messenger service server 110 .

In this way, after the encrypted first document file is transmitted to the electronic terminal 20 of the second member, a request for decryption of the encrypted first document file from the electronic terminal 20 of the second member is sent to the messenger service. When received by the server 110, the decryption unit 115 receives the encrypted first document file from the electronic terminal 20 of the second member, and identifies the member of the second member on the first member list. After checking whether information exists, if it is confirmed that member identification information of the second member exists in the first member list, the encrypted first document file is decrypted based on the encryption key.

At this time, according to an embodiment of the present invention, the decoding unit 115 may include a list extraction unit 117, an information confirmation unit 118 and a decoding processing unit 119.

When the decryption request is received from the electronic terminal 20 of the second member, the list extraction unit 117 receives the encrypted first document file from the electronic terminal 20 of the second member, and receives the encrypted first document file. After generating the first hash value by applying a first document file as an input to the hash function, the first hash value stored in correspondence with the first hash value from the list database based on the first hash value Extract the member list.

When the first member list is extracted, the information checking unit 118 checks whether member identification information of the second member exists on the first member list.

At this time, according to one embodiment of the present invention, the information confirmation unit 118 checks whether member identification information of the second member exists on the first member list, in order to provide more enhanced security. , It may further include a configuration for performing occupancy authentication based on the mobile phone number of each member.

In this regard, according to one embodiment of the present invention, in the member database 111, information on a preset mobile phone number of each member is additionally stored in correspondence with member identification information for each of the plurality of members. There may be.

At this time, the information verification unit 118 may include an authentication number sending unit 120 and a confirmation processing unit 121 .

When the first member list is extracted from the list database, the authentication number sending unit 120 transmits a reply message requesting a reply to the mobile phone number of the second member to the electronic terminal 20 of the second member, and , When the first mobile phone number is returned as a response to the reply message from the electronic terminal 20 of the second member, a one-time authentication number is generated, and the one-time authentication number is converted to the electronic terminal 20 of the second member. ), and then sends the short message to the receiving side of the first mobile phone number.

For example, when it is said that the first mobile phone number of '010-0000-1111' is returned from the electronic terminal 20 of the second member, the authentication number sending unit 120 sends a predetermined disposable number such as '23144'. After generating an authentication number and generating a short message instructing to input the one-time authentication number on the electronic terminal 20 of the second member, the first mobile phone number '010-0000-1111' is received. and send the short message.

Then, the second member can view the short message received in the mobile phone of the second member and input the one-time authentication number on the electronic terminal 20 of the second member.

In this way, as the second member checks the short message and inputs the one-time authentication number on the electronic terminal 20 of the second member, the messenger service server ( When the one-time authentication number is received in 110), the confirmation processing unit 121 confirms the member identification information stored in correspondence with the first mobile phone number from the member database 111 as member identification information of the second member, It is checked whether member identification information of the second member exists in the first member list.

When it is confirmed that the member identification information of the second member exists in the first member list, the decryption processing unit 119 confirms that the second member is a member having access to the first document file, Based on the encryption key, decryption of the encrypted first document file is performed.

At this time, according to one embodiment of the present invention, in the process of performing decryption on the encrypted first document file, the decryption processing unit 119 sends the second member's electronic terminal 20 to the second member's original document file. In order to check whether the electronic terminal possessed by , it may further include a configuration for performing electronic signature verification.

In this regard, according to one embodiment of the present invention, in the member database 111, the pre-issued public key for each of the plurality of members (the private key corresponding to the public key for each of the plurality of members) pre-stored in each member's electronic terminal) may be additionally stored.

At this time, if it is confirmed that the member identification information of the second member exists in the first member list, the decryption processing unit 119 generates random dummy data, and the second member's electronic terminal 20 ), and after transmitting the dummy data and the electronic signature request based on the dummy data, from the electronic terminal 20 of the second member, the electronic terminal 20 of the second member transmits the dummy data to the electronic terminal 20 of the second member. When the electronic signature value generated by encrypting with the first private key stored in the electronic terminal 20 of the second member is received, the electronic signature is stored in the member database 111 with the first public key for the second member. It is checked whether the decrypted value matches the dummy data, and if it is confirmed that the value matches the dummy data, the encrypted first document file may be decrypted based on the encryption key.

Specifically, when it is confirmed that the member identification information of the second member exists on the first member list through the information checking unit 118, the decryption processing unit 119 generates random dummy data, At the same time as the dummy data is transmitted to the electronic terminals 20 of the two members, an electronic signature request based on the dummy data may be transmitted.

Then, the electronic terminal 20 of the second member encrypts the dummy data with the first private key stored in the electronic terminal 20 of the second member and pre-issued to the second member to obtain an electronic signature value. can create

Then, the electronic terminal 20 of the second member may transmit the electronic signature value to the messenger service server 110 .

In this way, when the electronic signature value is received from the electronic terminal 20 of the second member to the messenger service server 110, the decryption processing unit 119 performs a task for the second member stored in the member database 111. 1 After decrypting the electronic signature value with the public key, it is checked whether the value obtained by decrypting the electronic signature value matches the dummy data, and if it is confirmed, the electronic signature value corresponds to the first public key. It can be confirmed that the value is properly signed with the first private key. Then, the decryption processing unit 119 may decrypt the encrypted first document file based on the encryption key.

According to the method described so far, when the decryption of the first document file is completed in the decryption unit 115, the transmission unit 116 opens the decrypted first document file, and according to the opening of the first document file After creating a viewing image of the document, the viewing image is transmitted to the electronic terminal 20 of the second member.

That is, when the decryption of the first document file is completed, the transmission unit 116 does not transmit the decrypted first document file itself to the electronic terminal 20 of the second member, but the decrypted first document file. After opening, a viewing image of the document according to the opening of the first document file may be generated, and the viewing image may be transmitted to the electronic terminal 20 of the second member.

As a result, only the browsing image in which the first document file is opened is received in the electronic terminal 20 of the second member, and the second member receives the open image of the first document file through the electronic terminal 20. can only see That is, the messenger service server 110 according to the present invention does not provide the first document file to the electronic terminal 20 of the second member, but provides only a viewing image in which the document file is opened, thereby providing the first document file. The problem of leaking files to the outside can be prevented in advance.

At this time, according to one embodiment of the present invention, the messenger service server 110 does not provide the first document file itself to the electronic terminal 20 of the second member in principle, but participates in the chat room, that is, When all members having access rights to the first document file agree, a configuration for providing the first document file to the electronic terminal 20 of the second member may be further included.

In this regard, the messenger service server 110 according to an embodiment of the present invention further includes a data vector generator 122, a vector transmitter 123, a vector restorer 124, and a document file transmitter 125. can include

After the viewing image is transmitted to the electronic terminal 20 of the second member through the transmission unit 116, the data vector generator 122 decodes the second member's electronic terminal 20. When a request for providing 1 document file is received, the decoded data constituting the first document file is divided into n pieces of data to generate n pieces of divided data, and then an n-dimensional data vector having the n pieces of divided data as components. generate

For example, if it is assumed that n is '5' because the number of members who have previously participated in the chat room is '5', the data vector generator 122 divides the decoded data constituting the first document file into 5 pieces. After splitting and generating 5 split data like 'D1, D2, D3, D4, D5', a 5-dimensional data vector having 5 split data as components is like '[D1 D2 D3 D4 D5]' can create

After generating n different n-dimensional one-hot vectors, the vector transmission unit 123 generates the n one-hot vectors for each electronic terminal of the n members included in the first member list. After designating and transmitting any one of the one-hot vectors one by one, and at the same time transmitting the data vector, for each electronic terminal of the n members, the one-hot vector transmitted to each electronic terminal and the above Sends a request for reply of a feedback vector based on the data vector.

In this regard, as in the above example, when n is '5', the vector transmission unit 123 may generate five different 5-dimensional one-hot vectors as shown in Table 2 below.

5 one-hot vectors [1 0 0 0 0] [0 1 0 0 0] [0 0 1 0 0] [0 0 0 1 0] [0 0 0 0 1]

Then, the vector transmission unit 123 designates and transmits one of the five one-hot vectors to the electronic terminal of each of the five members included in the first member list, one by one. At the same time, the data vector may be transmitted. In this regard, the vector transmitter 123 transmits '[1 0 0 0 0]' and the data vector '[D1 D2 D3 D4 D5]' to the electronic terminal of 'Member 1' among the five members. '[0 1 0 0 0]' and the data vector '[D1 D2 D3 D4 D5]' can be transmitted to the electronic terminal of 'Member 2', and 'Member 3' electronic terminal can transmit '[D1 D2 D3 D4 D5]'. [0 0 1 0 0]' and the data vector '[D1 D2 D3 D4 D5]' can be transmitted, and for the electronic terminal of 'member 4', '[0 0 0 1 0]' and the data vector '[D1 D2 D3 D4 D5]' can be transmitted, and '[0 0 0 0 1]' and the data vector '[D1 D2 D3 D4 D5]' can be transmitted to the electronic terminal of 'member 5'. .

After that, the vector transmission unit 123 may transmit a request for replying a feedback vector based on the one-hot vector transmitted to each electronic terminal and the data vector to each electronic terminal of the five members.

The vector restoration unit 124 is a feedback vector generated by each electronic terminal in response to the reply request from the electronic terminal of each of the n members (the feedback vector generated by the electronic terminal of each of the n members is , which is an n-dimensional vector generated by performing Hadamard product between the one-hot vector received at each electronic terminal and the data vector) is received, the received from each electronic terminal of the n members The data vector is restored by summing all the feedback vectors.

Here, the Hadamard product means an operation of multiplying each component in a matrix or vector of the same size. For example, when there are vectors '[a b c]' and '[x y z]', if the Hadamard product between the two vectors is calculated, the vector '[ax by cz]' can be calculated.

In this regard, as in the above example, when n is set to '5' and the vector transmission unit 123 transmits '[1 0 0 0 0]' to the electronic terminal of 'Member 1' and the data vector '[ D1 D2 D3 D4 D5]' is transmitted, and '[0 1 0 0 0]' and the data vector '[D1 D2 D3 D4 D5]' are transmitted to the electronic terminal of 'Member 2'. Suppose that '[0 0 1 0 0]' and the data vector '[D1 D2 D3 D4 D5]' are transmitted to the electronic terminal of 'member 4', and '[0 0 0 1 0]' is transmitted to the electronic terminal of 'member 4'. ' and the data vector '[D1 D2 D3 D4 D5]' are transmitted, and '[0 0 0 0 1]' and the data vector '[D1 D2 D3 D4 D5]' are transmitted to the electronic terminal of 'Member 5'. Suppose ' is sent.

Then, the electronic terminal of 'Member 1' calculates the Hadamard product between the one-hot vector '[1 0 0 0 0]' and the data vector '[D1 D2 D3 D4 D5]', thereby calculating '[D1 0 0 0]'. 0 0]' to generate a feedback vector and send a reply to the messenger service server 110, and the electronic terminal of 'Member 2' uses the one-hot vector '[0 1 0 0 0]' and the data vector. By calculating the Hadamard product between '[D1 D2 D3 D4 D5]', a feedback vector called '[0 D2 0 0 0]' can be generated and returned to the messenger service server 110, and 'Member 3' The electronic terminal of '[0 0 1 0 0]', which is a one-hot vector, and '[D1 D2 D3 D4 D5]', which is the data vector, calculates the Hadamard product, which is '[0 0 D3 0 0]'. A feedback vector can be generated and returned to the messenger service server 110, and the electronic terminal of 'Member 4' has the one-hot vector '[0 0 0 1 0]' and the data vector '[D1 D2 D3]. By calculating the Hadamard product between D4 D5]', a feedback vector of '[0 0 0 D4 0]' can be generated and returned to the messenger service server 110, and the electronic terminal of 'Member 5' can generate a circle- By calculating the Hadamard product between the hot vector '[0 0 0 0 1]' and the data vector '[D1 D2 D3 D4 D5]', a feedback vector called '[0 0 0 0 D5]' is generated, A reply can be made to the messenger service server 110 .

In this way, the messenger service server 110 receives a feedback vector of '[D1 0 0 0 0]' from the electronic terminal of 'Member 1' and receives '[0 D2 0 0 0]' from the electronic terminal of 'Member 2'. A feedback vector of 'Member 3' is received, a feedback vector of '[0 0 D3 0 0]' is received from the electronic terminal of 'Member 3', and a feedback of '[0 0 0 D4 0]' is received from the electronic terminal of 'Member 4'. When the vector is received and a feedback vector of '[0 0 0 0 D5]' is received from the electronic terminal of 'member 5', the vector restoration unit 124 receives the feedback received from the electronic terminal of each of the five members. By summing all the vectors, the data vector '[D1 D2 D3 D4 D5]' can be restored.

When the data vector is restored by the vector restoration unit 124, the document file transmission unit 125 adds up the n pieces of divided data included as components in the restored data vector to restore the first document file. Then, the restored first document file is transmitted to the electronic terminal 20 of the second member.

In relation to this, as in the above example, when the data vector of '[D1 D2 D3 D4 D5]' is restored by the vector restoration unit 124, the document file transmission unit 125 includes the data vector as a component. After restoring the first document file by summing the five pieces of data 'D1, D2, D3, D4, D5', the restored first document file will be transmitted to the electronic terminal 20 of the second member. can That is, in that the first document file can be restored only when feedback vectors are normally returned from all of the five members, the messenger service server 110 of the present invention obtains the consent of all members who have participated in the chat room. Only when obtained, service operation is possible in the form of providing the original document file to a specific member.

3 is a flowchart illustrating an operating method of a messenger service server enabling secure sharing of document files through a messenger service according to an embodiment of the present invention.

In step S310, a member database in which preset member identification information for each of a plurality of members subscribed to the messenger service is stored is maintained.

In step S320, a first document file is received from the electronic terminal of a first member among n (n is a natural number equal to or greater than 2) members participating in the chat room opened through the messenger service. When a secure sharing request for is received, the first document file is encrypted with a preset encryption key, and then the encrypted first document file is posted on the chat room, so that the first document file encrypted through the chat room is displayed. Make it available for download.

In step S330, member identification information of each of the n members is checked based on the member database, and a first member list composed of member identification information of each of the n members is generated, and then the first member list is generated. A list is designated as a list of members having access to the first document file and stored in the list database.

In step S340, when a request to download the encrypted first document file is received from the electronic terminal of a second member, which is one of the n members, the first document file encrypted by the electronic terminal of the second member. send

In step S350, if a request for decryption of the encrypted first document file is received from the electronic terminal of the second member after the encrypted first document file is transmitted to the electronic terminal of the second member, the first document file is encrypted. 2 After receiving the encrypted first document file from the member's electronic terminal and confirming whether the member identification information of the second member exists on the first member list, the second member's name on the first member list If it is confirmed that member identification information exists, the encrypted first document file is decrypted based on the encryption key.

In step S360, when the decryption of the first document file is completed, the decrypted first document file is opened, a viewing image of the document according to the opening of the first document file is generated, and the viewing image is displayed as the above. It is transmitted to the electronic terminal of the second member.

At this time, according to one embodiment of the present invention, in step S330, when the first member list is generated, a first hash value is generated by applying the encrypted first document file as an input to a preset hash function, and then , The first hash value and the first member list may be stored in correspondence with each other on the list database.

At this time, in step S350, when the decryption request is received from the electronic terminal of the second member, the encrypted first document file is received from the electronic terminal of the second member, and the encrypted first document file is sent to the electronic terminal. Applying a hash function as an input to generate the first hash value, and then extracting the first member list stored in correspondence with the first hash value from the list database based on the first hash value. , When the first member list is extracted, checking whether member identification information of the second member exists on the first member list, and member identification information of the second member exists on the first member list. If it is confirmed that the document file is encrypted, performing decryption on the encrypted first document file based on the encryption key.

Further, according to an embodiment of the present invention, the member database may store information on a preset mobile phone number of each member additionally corresponding to member identification information for each of the plurality of members.

In this case, in the checking step, when the first member list is extracted, a reply message requesting a reply of the mobile phone number of the second member is transmitted to the electronic terminal of the second member, and the electronic terminal of the second member is sent. In response to the reply message, if the first mobile phone number is returned, a one-time authentication number is generated, and a short message instructing input of the one-time authentication number on the electronic terminal of the second member is generated from , Sending the short message to the receiver of the first mobile phone number, and as the second member checks the short message and inputs the one-time authentication number on the electronic terminal of the second member, the second member confirms the short message. 2 When the one-time authentication number is received from the member's electronic terminal, member identification information stored in correspondence with the first mobile phone number is checked from the member database as member identification information of the second member, and then the first member list and checking whether member identification information of the second member is present on the second member.

In addition, according to one embodiment of the present invention, in the member database, a pre-issued public key for each of the plurality of members (the private key corresponding to the public key for each of the plurality of members is the digital key of each member). pre-stored in the terminal) may be additionally stored.

In this case, in the decryption step, if it is confirmed that the member identification information of the second member exists in the first member list, random dummy data is generated, and the dummy data is transferred to the electronic terminal of the second member. and, after transmitting the electronic signature request based on the dummy data, from the electronic terminal of the second member, the electronic terminal of the second member stores the dummy data in the electronic terminal of the second member. When an electronic signature value generated by encrypting with 1 private key is received, it is checked whether a value obtained by decrypting the electronic signature value with a first public key for the second member stored in the member database matches the dummy data; If it is confirmed that they match, the encrypted first document file may be decrypted based on the encryption key.

Further, according to an embodiment of the present invention, the operating method of the messenger service server may include the first document file decrypted from the electronic terminal of the second member after the viewing image is transmitted to the electronic terminal of the second member. When a request for provision of is received, dividing the data constituting the decoded first document file into n pieces of data, generating n pieces of split data, and then generating an n-dimensional data vector having the n pieces of split data as components. Step, after generating n different n-dimensional one-hot vectors, for each electronic terminal of the n members included in the first member list, any one of the n one-hot vectors is selected. At the same time as designating and transmitting one-hot vectors one by one, after transmitting the data vectors, for each electronic terminal of the n members, based on the one-hot vector transmitted to each electronic terminal and the data vector Transmitting a reply request of one feedback vector, from an electronic terminal of each of the n members, in response to the reply request, a feedback vector generated by each electronic terminal (generated by each electronic terminal of the n members) One feedback vector is an n-dimensional vector generated by performing Hadamard multiplication between a one-hot vector received at each electronic terminal and the data vector) is received, the feedback received from each electronic terminal of the n members restoring the data vector by summing all vectors; and when the data vector is restored, summing the n pieces of divided data included as components in the restored data vector to restore the first document file; The method may further include transmitting the restored first document file to an electronic terminal of the second member.

In the above, the operating method of the messenger service server according to an embodiment of the present invention has been described with reference to FIG. 3 . Here, since the operation method of the messenger service server according to an embodiment of the present invention may correspond to the configuration of the operation of the messenger service server 110 described with reference to FIGS. 1 and 2, a detailed description thereof is omitted. I'm going to do it.

A method of operating a messenger service server according to an embodiment of the present invention may be implemented as a computer program stored in a storage medium for execution through a combination with a computer.

In addition, the operating method of the messenger service server according to an embodiment of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on the medium may be those specially designed and configured for the present invention or those known and usable to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. - includes hardware devices specially configured to store and execute program instructions, such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter, as well as machine language codes such as those produced by a compiler.

As described above, the present invention has been described by specific details such as specific components and limited embodiments and drawings, but these are provided to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments. , Those skilled in the art in the field to which the present invention belongs can make various modifications and variations from these descriptions.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and it will be said that not only the claims to be described later, but also all modifications equivalent or equivalent to these claims belong to the scope of the present invention. .

110: messenger service server
111: member database 112: file encryption unit
113: list designation unit 114: file transmission unit
115: decoding unit 116: transmission unit
117: list extraction unit 118: information confirmation unit
119: decryption processing unit 120: authentication number sending unit
121: confirmation processing unit 122: data vector generation unit
123: vector transmission unit 124: vector restoration unit
125: document file transmission unit
10: Electronic terminal of the first member
20: Electronic terminal of the second member

Claims (12)

A messenger service server enabling secure sharing of document files through a messenger service,
a member database storing preset member identification information for each of a plurality of members subscribed to the messenger service;
When a first document file is received from the electronic terminal of a first member who is any one of n (n is a natural number equal to or greater than 2) members participating in the chat room opened through the messenger service, a secure sharing request for the first document file is received. is received, encrypts the first document file with a preset encryption key, and then posts the encrypted first document file in the chat room so that the encrypted first document file can be downloaded through the chat room. a file encryption unit that does;
After verifying member identification information of each of the n members based on the member database and generating a first member list composed of member identification information of each of the n members, the first member list is converted into the first member list. a list designation unit for designating a list of members having access to document files and storing them in a list database;
File transmission for transmitting the encrypted first document file to the electronic terminal of the second member when a download request of the encrypted first document file is received from the electronic terminal of a second member who is one of the n members. wealth;
After the encrypted first document file is transmitted to the electronic terminal of the second member, when a request for decryption of the encrypted first document file is received from the electronic terminal of the second member, the electronic terminal of the second member After receiving the encrypted first document file from and confirming whether member identification information of the second member exists on the first member list, member identification information of the second member exists on the first member list. a decryption unit for decrypting the encrypted first document file based on the encryption key, if it is confirmed that it does so; and
When the decryption of the first document file is completed, the decrypted first document file is opened, a viewing image of the document according to the opening of the first document file is created, and then the viewing image is transferred to the electronic device of the second member. Transmitting unit that transmits to the terminal
including,
The list designator
When the first member list is generated, a first hash value is generated by applying the encrypted first document file as an input to a preset hash function, and then the first hash value and the first member are stored on the list database. Store the list in correspondence with each other,
The decoding unit
When the decryption request is received from the electronic terminal of the second member, the encrypted first document file is received from the electronic terminal of the second member, and the encrypted first document file is applied as an input to the hash function a list extractor configured to extract the first member list corresponding to the first hash value from the list database based on the first hash value after generating the first hash value;
an information checking unit that checks whether member identification information of the second member exists on the first member list when the first member list is extracted; and
If it is confirmed that the member identification information of the second member exists in the first member list, a decryption processing unit that decrypts the encrypted first document file based on the encryption key.
A messenger service server including a. delete According to claim 1,
In the member database, information about a preset mobile phone number of each member is additionally stored in correspondence with member identification information for each of the plurality of members,
The information verification unit
When the first member list is extracted, a reply message requesting a reply of the mobile phone number of the second member is transmitted to the electronic terminal of the second member, and from the electronic terminal of the second member, information about the reply message is sent. As a response, when the first mobile phone number is returned, a one-time authentication number is generated, and a short message instructing input of the one-time authentication number on the electronic terminal of the second member is generated, and then the first mobile phone number is entered. an authentication number sending unit for sending the short message to the receiving side; and
As the second member checks the short message and inputs the one-time authentication number on the electronic terminal of the second member, when the one-time authentication number is received from the electronic terminal of the second member, the member database A confirmation processing unit that checks the stored member identification information corresponding to the first mobile phone number as the member identification information of the second member and then confirms whether the member identification information of the second member exists in the first member list.
A messenger service server including a. According to claim 1,
In the member database, a pre-issued public key for each of the plurality of members, in which a private key corresponding to the public key for each of the plurality of members is pre-stored in the electronic terminal of each member, is additionally stored. is done,
The decryption processing unit
If it is confirmed that the member identification information of the second member exists on the first member list, random dummy data is generated and the dummy data and the dummy data are transmitted to the electronic terminal of the second member. After transmitting the based digital signature request, the electronic terminal of the second member encrypts and generates the dummy data with the first private key stored in the electronic terminal of the second member from the electronic terminal of the second member. When an electronic signature value is received, it is checked whether the value obtained by decrypting the electronic signature value with the first public key for the second member stored in the member database matches the dummy data, and if it is confirmed to match, The messenger service server, characterized in that performing decryption on the encrypted first document file based on the encryption key. According to claim 1,
After the viewing image is transmitted to the electronic terminal of the second member, when a request for providing the decrypted first document file is received from the electronic terminal of the second member, data constituting the decrypted first document file a data vector generating unit that divides into n pieces of data, generates n pieces of divided data, and then generates an n-dimensional data vector having the n pieces of divided data as components;
After generating n different n-dimensional one-hot vectors, for each electronic terminal of the n members included in the first member list, any one one-hot vector of the n one-hot vectors is generated. At the same time as designating and transmitting hot vectors one by one, after transmitting the data vectors, for each electronic terminal of the n members, feedback based on the one-hot vector transmitted to each electronic terminal and the data vector a vector transmitter for transmitting a vector reply request;
A feedback vector generated by each electronic terminal in response to the reply request from the electronic terminal of each of the n members - the feedback vector generated by each electronic terminal of the n members is received by each electronic terminal When -, which is an n-dimensional vector generated by performing Hadamard product between a one-hot vector and the data vector, is received, all of the feedback vectors received from the electronic terminals of each of the n members are summed up, a vector restoration unit to restore the data vector; and
When the data vector is restored, the first document file is restored by summing the n pieces of divided data included as components in the restored data vector, and then the restored first document file is converted into the electronic device of the second member. Document file transmission unit to transmit to the terminal
A messenger service server further comprising a. A method of operating a messenger service server enabling secure sharing of document files through a messenger service,
maintaining a member database in which preset member identification information for each of a plurality of members subscribed to the messenger service is stored;
When a first document file is received from the electronic terminal of a first member who is any one of n (n is a natural number equal to or greater than 2) members participating in the chat room opened through the messenger service, a secure sharing request for the first document file is received. is received, encrypts the first document file with a preset encryption key, and then posts the encrypted first document file in the chat room so that the encrypted first document file can be downloaded through the chat room. doing;
After verifying member identification information of each of the n members based on the member database and generating a first member list composed of member identification information of each of the n members, the first member list is converted into the first member list. specifying a list of members having access to document files and storing them in a list database;
transmitting the encrypted first document file to the electronic terminal of the second member when a request to download the encrypted first document file is received from the electronic terminal of a second member who is one of the n members;
After the encrypted first document file is transmitted to the electronic terminal of the second member, when a request for decryption of the encrypted first document file is received from the electronic terminal of the second member, the electronic terminal of the second member After receiving the encrypted first document file from and confirming whether member identification information of the second member exists on the first member list, member identification information of the second member exists on the first member list. if it is confirmed that it does, decrypting the encrypted first document file based on the encryption key; and
When the decryption of the first document file is completed, the decrypted first document file is opened, a viewing image of the document according to the opening of the first document file is created, and then the viewing image is transferred to the electronic device of the second member. Step to transmit to terminal
including,
The step of storing in the list database is
When the first member list is generated, a first hash value is generated by applying the encrypted first document file as an input to a preset hash function, and then the first hash value and the first member are stored on the list database. Store the list in correspondence with each other,
The decryption step is
When the decryption request is received from the electronic terminal of the second member, the encrypted first document file is received from the electronic terminal of the second member, and the encrypted first document file is applied as an input to the hash function extracting the first member list stored corresponding to the first hash value from the list database based on the first hash value after generating the first hash value;
checking whether member identification information of the second member exists on the first member list when the first member list is extracted; and
If it is confirmed that the member identification information of the second member exists in the first member list, decrypting the encrypted first document file based on the encryption key.
A method of operating a messenger service server comprising a. delete According to claim 6,
In the member database, information about a preset mobile phone number of each member is additionally stored in correspondence with member identification information for each of the plurality of members,
The steps to check are
When the first member list is extracted, a reply message requesting a reply of the mobile phone number of the second member is transmitted to the electronic terminal of the second member, and from the electronic terminal of the second member, information about the reply message is sent. As a response, when the first mobile phone number is returned, a one-time authentication number is generated, and a short message instructing input of the one-time authentication number on the electronic terminal of the second member is generated, and then the first mobile phone number is entered. sending the short message to a receiving party; and
As the second member checks the short message and inputs the one-time authentication number on the electronic terminal of the second member, when the one-time authentication number is received from the electronic terminal of the second member, the member database Confirming member identification information stored in correspondence with the first mobile phone number as member identification information of the second member, and then confirming whether member identification information of the second member exists in the first member list.
A method of operating a messenger service server comprising a. According to claim 6,
In the member database, a pre-issued public key for each of the plurality of members, in which a private key corresponding to the public key for each of the plurality of members is pre-stored in the electronic terminal of each member, is additionally stored. is done,
The step of performing the decryption is
If it is confirmed that the member identification information of the second member exists on the first member list, random dummy data is generated and the dummy data and the dummy data are transmitted to the electronic terminal of the second member. After transmitting the based digital signature request, the electronic terminal of the second member encrypts and generates the dummy data with the first private key stored in the electronic terminal of the second member from the electronic terminal of the second member. When an electronic signature value is received, it is checked whether the value obtained by decrypting the electronic signature value with the first public key for the second member stored in the member database matches the dummy data, and if it is confirmed to match, A method of operating a messenger service server, characterized in that performing decryption on the encrypted first document file based on the encryption key. According to claim 6,
After the viewing image is transmitted to the electronic terminal of the second member, when a request for providing the decrypted first document file is received from the electronic terminal of the second member, data constituting the decrypted first document file dividing into n pieces of data, generating n pieces of split data, and then generating an n-dimensional data vector having the n pieces of split data as components;
After generating n different n-dimensional one-hot vectors, for each electronic terminal of the n members included in the first member list, any one one-hot vector of the n one-hot vectors is generated. At the same time as designating and transmitting hot vectors one by one, after transmitting the data vectors, for each electronic terminal of the n members, feedback based on the one-hot vector transmitted to each electronic terminal and the data vector Sending a vector reply request;
A feedback vector generated by each electronic terminal in response to the reply request from the electronic terminal of each of the n members - the feedback vector generated by each electronic terminal of the n members is received by each electronic terminal When -, which is an n-dimensional vector generated by performing Hadamard product between a one-hot vector and the data vector, is received, all of the feedback vectors received from the electronic terminals of each of the n members are summed up, restoring the data vector; and
When the data vector is restored, the first document file is restored by summing the n pieces of divided data included as components in the restored data vector, and then the restored first document file is converted into the electronic device of the second member. Step to transmit to terminal
Method of operating the messenger service server further comprising a. Claim 6, claim 8, claim 9 or claim 10 of any one of the method through a combination with a computer to execute a computer program recorded on a computer-readable recording medium. A computer program stored in a storage medium for executing the method of any one of claims 6, 8, 9 or 10 through a combination with a computer.

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