KR20230055984A - Data transmission and access control method, recording medium and data transmission and access control system for performing the same - Google Patents

Abstract

The present invention relates to a data transmission and access control system, which provides a data transmission service based on a blockchain network, comprising: a transmitting node for transmitting data to be shared; a receiving node for receiving the data to be shared; and a relay node for receiving a keyword for the data to be shared from the receiving node, checking the transmitting node, which provides the data to be shared corresponding to the keyword, and establishing a P2P session between the receiving node and the transmitting node, wherein the receiving node, the transmitting node and the relay node are nodes constituting the blockchain network. Accordingly, personal information can be protected and data can be transmitted safely and swiftly using a simple user authentication method without going through a complicated log-in process.

Description

Data transmission and access control method, recording medium and data transmission and access control system for performing the same

The present invention relates to a data transmission and access control method that enables simple and safe data transmission through a messenger without complicated program installation and authentication related to log-in, and a recording medium and data transmission and access control system for performing the same.

In general, in order to access and control data stored in a terminal from another terminal, it must be transmitted from the terminal to another terminal through mail, dropbox, cloud storage, or the like.

At this time, a login process is required to control data from another terminal, but frequent login process is cumbersome, and the key log recorded during the login process is a factor that increases the risk of leakage of personal information.

And in the case of cloud storage, it is vulnerable to attacks that prevent the central server from operating properly due to its centralized structure, and the possibility of forgery/falsification of information and retransmission attack due to information theft is always present, which can cause confusion.

Therefore, there is a need for a method that not only transmits data safely and quickly, but also does not require a complicated login process.

Korean Patent Publication No. 10-2003-0080318

The present invention has been made to solve the above problems, and an object of the present invention is to protect personal information by using a simple authentication method without going through a complicated login process, as well as to transmit data safely and quickly. It is to provide a data transmission and access control method, a recording medium and a data transmission and access control system for performing the same.

A data transmission and access control system for providing a data transmission service based on a blockchain network according to an embodiment of the present invention for achieving the above object includes a transmission node for transmitting data to be shared; a receiving node receiving the sharing target data; and a relay node that receives a keyword for the sharing target data from the receiving node, checks the transmitting node that provides the sharing target data corresponding to the keyword, and establishes a P2P session between the receiving node and the transmitting node. Including, the receiving node, the transmitting node and the relay node are nodes constituting the blockchain network.

The transmission node creates a smart contract including a file contract related to the data to be shared and a user contract related to the transmission node, and the file contract includes metadata and file transmission/reception log information of the data to be shared. And, the user contract may include a peer ID of the transmitting node, a service ID, and encrypted password information for logging in to the blockchain network.

In addition, the relay node may search for a smart contract corresponding to the keyword and transmit a service ID of the searched smart contract to the receiving node.

The receiving node logs in anonymously to the data transmission service through a connection window including the service ID of the searched smart contract, and the relay node checks the peer IDs of the sending node and the receiving node to communicate with the sending node. The P2P session between receiving nodes may be established.

In addition, the transmitting node may transmit the data to be shared through a chat window to the receiving node where the P2P session is established, and update file transmission/reception log information of the smart contract.

and a notification node generating notification information for notifying establishment of the P2P session and transmitting the notification information to at least one of the transmission node and the reception node when the relay node establishes the P2P session. can

On the other hand, a data transmission and access control method in a data transmission and access control system that provides a data transmission service based on a blockchain network according to an embodiment of the present invention for achieving the above object is the data transmission and access control system includes a receiving node, a transmitting node, and a relay node constituting the blockchain network, and the relay node receives a keyword for sharing target data from the receiving node; checking, by the relay node, a transmission node providing the sharing target data corresponding to the keyword; establishing, by the relay node, a P2P session between the receiving node and the transmitting node; transmitting, by the transmission node, the sharing target data; and receiving, by the reception node, the data to be shared.

and generating, by the sending node, a smart contract including a file contract related to the subject data to be shared and a user contract related to the sending node, wherein the file contract transmits and receives metadata and files of the subject data to be shared. log information, and the user contract may include a peer ID of the sending node, a service ID, and encrypted password information for logging in to the blockchain network.

In addition, the step of checking the transmission node may include: the relay node searching for the smart contract corresponding to the keyword; The relay node may transmit the service ID of the searched smart contract to the receiving node.

The receiving node further includes anonymously logging in to the data transmission service through a connection window including the service ID of the searched smart contract, and in the step of establishing the P2P session, the peers of the transmitting node and the receiving node The P2P session between the sending node and the receiving node may be established by checking the ID.

In addition, in the transmitting step, the sending node may transmit the data to be shared to the receiving node with which the P2P session is established through a chat window, and update file transmission/reception log information of the smart contract.

And the data transmission and access control system further includes a notification node constituting the blockchain network, and after the step of establishing the P2P session by the notification node, notification information for notifying establishment of the P2P session is generated. and transmitting the notification information to at least one of the transmission node and the reception node.

On the other hand, a recording medium according to an embodiment of the present invention for achieving the above object is a computer-readable recording medium on which a computer program for performing a data transmission and access control method is recorded.

According to one aspect of the present invention described above, by providing a data transmission and access control method, a recording medium and a data transmission and access control system for performing the same, without going through a complicated log-in process, using a simple authentication method to personal information and data can be transmitted safely and quickly.

1 is a diagram for explaining the configuration of a data transmission and access control system according to an embodiment of the present invention;
2 is a diagram for explaining a data transmission service provided by a data transmission and access control system according to an embodiment of the present invention;
3 is a diagram for explaining information stored in a data transmission and access control system according to an embodiment of the present invention;
4 is a diagram for explaining a process of transmitting a notification when a chat window is created in a data transmission and access control system according to an embodiment of the present invention;
5 is a flowchart for explaining a data transmission and access control method in a data transmission and access control system according to an embodiment of the present invention, and
6 is a flowchart for explaining the data transmission and access control method of FIG. 5 in more detail.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The detailed description of the present invention which follows refers to the accompanying drawings which illustrate, by way of illustration, specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable one skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention are different from each other but are not necessarily mutually exclusive. For example, specific shapes, structures, and characteristics described herein may be implemented in another embodiment without departing from the spirit and scope of the invention in connection with one embodiment. Additionally, it should be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the invention. Accordingly, the detailed description set forth below is not to be taken in a limiting sense, and the scope of the present invention, if properly described, is limited only by the appended claims, along with all equivalents as claimed by those claims. Like reference numbers in the drawings indicate the same or similar function throughout the various aspects.

Components according to the present invention are components defined by functional division rather than physical division, and may be defined by the functions each performs. Each of the components may be implemented as hardware or program codes and processing units that perform respective functions, and the functions of two or more components may be implemented by being included in one component. Therefore, the names given to the components in the following embodiments are not to physically distinguish each component, but to imply the representative function performed by each component, and the names of the components indicate the present invention. It should be noted that the technical idea of is not limited.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the drawings.

1 is a diagram for explaining the configuration of a data transmission and access control system 10 according to an embodiment of the present invention, Figure 2 is provided by the data transmission and access control system 10 according to an embodiment of the present invention A diagram for explaining a data transmission service, Figure 3 is a diagram for explaining information stored in the data transmission and access control system 10 according to an embodiment of the present invention, and Figure 4 is an embodiment of the present invention It is a diagram for explaining a process of transmitting a notification when a chat window is created in the data transmission and access control system 10 according to.

The data transmission and access control system (10, hereinafter referred to as the system) according to this embodiment is prepared to safely and quickly transmit and receive necessary data between nodes while protecting personal information through anonymous login without a login process of recording a key log. do.

In addition, the system 10 according to this embodiment may provide a data transmission service based on a blockchain network (BN).

To this end, the system 10 may include a transmission node 100, a reception node 200, and a relay node 300. In addition, the transmitting node 100, the receiving node 200, and the relay node 300 may have software (application) installed and executed to perform data transmission and access control methods.

In addition, the transmission node 100, the reception node 200, and the relay node 300 constituting the system 10 may constitute a blockchain network (BN). A blockchain network (BN) is a form of distributed database managed through a peer to peer (P2P) network.

Blockchain enables transparent operation of various applications such as smart contracts and electronic voting based on blockchain technology that stores and stores ledgers containing transaction information in multiple connected computers rather than in one central server. extensibility can be provided.

In addition, the nodes constituting the blockchain store identical copies, and once recorded, data cannot be tampered with or forged, so there are advantages such as information reliability, transparency, and traceability. The blockchain network (BN) in the system 10 of the present invention may be provided as a distributed computing platform for implementing distributed application functions.

The transmitting node 100, the receiving node 200, and the relay node 300 are terminals possessed by the user. Examples of such terminals may include desktops, tablets, smart phones, smart watches, notebooks, and the like, devices, apparatuses, terminals, user equipment (UE), mobile stations (MS), and wireless devices ( It may also be called other terms such as wireless device) and handheld device.

Also, the data transmission service provided by the system 10 may be an anonymous login and messenger-based data transmission service.

The transmission node 100 may be a node in which data to be shared is stored in a local storage or a node linked to a cloud in which data to be shared is stored.

In addition, file data and login data may be stored in the local storage of the transmitting node 100 .

As described above, the messenger service, which is a data transmission service, may be provided in the form of an app or web. File data and login data are the terminal of the transmission node 100 when the messenger service is in the form of an app. Can be stored in internal storage.

If the messenger service is in the form of a web, it may be stored in a local web storage.

The file data may include a file name, file size, file type, and other information related to the file (etc. info).

In the login data, for example, a session or token generated in conjunction with a cloud service, a service ID, and an encrypted password may be stored.

Such a transmitting node 100 may create a smart contract (SC) related to data to be shared.

The smart contract (SC) may include a file contract (FC) related to data to be shared and a user contract (UC) related to the transmission node 100.

Specifically, as shown in FIG. 3, the file contract (FC) may include metadata (File Info) and file transmission/reception log information (File Send/Receive Info) of data to be shared.

The user contract (UC) may include a peer ID of the transmission node 100, a service ID, and encrypted password information for logging in to the blockchain network.

In addition, the peer ID, service ID, and encrypted password information for logging in to the blockchain network (BN) of the sending node 100 stored in the user contract (UC) match each other. can be stored as is.

Here, the peer ID is an ID corresponding to account information of the blockchain network (BN) and may be information for identifying a node on the blockchain network (BN). Also, the peer ID may be prepared in hexadecimal as shown in FIGS. 2 to 4 .

Also, a service ID is an ID for providing a data transmission service, and may vary depending on a messenger, and may be IDs provided for each node within a service but not overlapping with each other.

When the P2P session is established through the relay node 300, the transmitting node 100 may transmit data to be shared to the receiving node 200 through a chat window.

That is, the transmitting node 100 may transmit data to be shared through a chat window to the receiving node 200 with which the P2P session is established.

In addition, when the transmitting node 100 transmits data to be shared through a chat window, the target data to be shared stored in the local storage of the transmitting node 100 as well as cloud services for which the transmitting node 100 provides a messenger service and cloud storage When the account is interlocked, the transmission node 100 may access the corresponding cloud storage and upload or import a file to be shared.

In addition, the transmission node 100 may update file send/receive log information (File send/receive Info) of the smart contract (SC).

In addition, when receiving a request for providing a file to be shared, the transmission node 100 may log in anonymously to the data transmission service in the same manner as the anonymous login method of the reception node 200 to be described later.

Meanwhile, the reception node 200 is a node that receives target data to be shared, and may transmit keywords for target data to be received to the relay node 300.

In addition, the receiving node 200 may log in anonymously to the data transmission service through the connection window including the service ID of the searched smart contract (SC).

As shown in FIG. 2 , a QR code or a service ID of the transmission node 100 may be provided to the connection window for anonymous login.

Accordingly, the receiving node 200 may scan the QR code or input the service ID of the transmitting node 100 that owns the data to be shared in a messenger provided in the form of a web or app.

Thereafter, the receiving node 200 receives the peer ID of the transmitting node 100, and when a P2P session is established through the relay node 300, a chat window through which data to be shared can be received from the transmitting node 100. this can be created.

In addition, the receiving node 200 may receive the download link or data of the data to be shared through the chat window and store them in the terminal of the receiving node 200 .

Meanwhile, the relay node 300 may receive a keyword for sharing target data from the reception node 200 .

Also, the relay node 300 may check the transmission node 100 that provides sharing target data corresponding to the keyword on the blockchain network BN.

To this end, the relay node 300 may search for a smart contract (SC) corresponding to the keyword among the smart contracts (SC) stored in the blockchain network (BN).

In addition, the relay node 300 may transmit the service ID of the searched smart contract (SC) to the receiving node 200. Accordingly, the receiving node 200 may receive an access window including a service ID transmitted by the relay node 300 through a web or app, and may log in anonymously through the access window.

Also, the relay node 300 may establish a P2P session between the receiving node 200 inputting the keyword and the transmitting node 100 providing the data to be shared.

In detail, the relay node 300 can establish a P2P session between the sending node 100 and the receiving node 200 by checking the peer IDs of the sending node 100 and the receiving node 200 .

When a P2P session is established through the relay node 300, a dialog window for transmitting and receiving data to be shared is created between the transmission node 100 and the reception node 200, and the transmission node 100 and the reception node 200 generate You can share the data to be shared within the chat window.

This relay node 300 may be a node randomly selected from among nodes in the blockchain network (BN).

In addition, the relay node 300 may match and store peer IDs and IP addresses of the transmitting node 100 and the receiving node 200, respectively.

In addition, when data cannot be directly transmitted between the transmission node 100 and the reception node 200, the relay node 300 may receive a request for transmission of data to be shared from the transmission node 100 to the reception node 200. In addition, the relay node 300 may relay the sharing target data received from the transmission node 100 and transmit it to the reception node 200 .

Whether to preserve data in the chat window created through anonymous login may be an option of the transmitting node 100 or the receiving node 200, and data transmission may be possible from all nodes participating in the created chat window.

Therefore, the system 10 according to an embodiment of the present invention can transmit data safely and quickly as well as protect personal information by using a simple authentication method without going through a complicated log-in process.

The system 10 according to an embodiment of the present invention may be provided by further including a notifying node 400 .

When the relay node 300 establishes the P2P session, the notification node 400 may generate notification information for notifying establishment of the P2P session.

Also, the notification node 400 may transmit notification information to at least one of the transmission node 100 and the reception node 200 .

4 is an example of a process in which the notification node 400 transmits notification information through a blockchain network (BN) and an event handler engine when a P2P session is established through the relay node 300.

Specifically, FIG. 4 is a diagram showing, as an example, a case where A, the sending node 100, anonymously enters a chat window created by B, the receiving node 200, and the sending node 100 A entered the chat window. When an event log is generated, the notification node 400 may detect the occurrence of an event.

In FIG. 4, it has been described that the sending node 100 generates an event log when the sending node 100 enters the chat window created by the receiving node 200, but this is only an example for convenience of explanation and must be It is not limited to this.

For example, after the sending node (100, for example node A) enters a chat window created by any one receiving node (200, for example node B), at least one other receiving node (200, for example node C) In the case where a group is formed by additionally entering the chat window, node C, which is the additionally entering receiving node 200, may create an event log. In this case, the notification node 400 may transmit notification information to both node A, which is the transmitting node 100, and node B, which is the receiving node 200, both entering the chat window.

And all nodes constituting the blockchain network (BN) in the system 10 of the present invention can drive the event handler engine.

For example, when an event of transmitting a file occurs and the file transmission event is stored in the blockchain BN, all nodes included in the blockchain BN can detect the event through their own event handlers. Therefore, when the notification node 400 among all nodes detects the corresponding event, it can be transmitted as notification information.

And the event handler engine selects the notification node 400 within the blockchain network (BN), and allows the selected node to provide notification service locally.

In this notifying node 400, the relay node 300 is selected as the notifying node 400 or a node different from the relay node 300 among the nodes constituting the blockchain network (BN) is selected as the notifying node 400. may be

Further, the notification information may include notification content and an ID for identifying a receiver, which is a node to receive the notification content, and a sender, which is a node that sends the notification content. Here, the ID may include at least one of a service ID and a peer ID.

The notification node 400 may store a user device token (userDeviceToken) in advance in a user database (User DB) as shown in FIG. 4, and transmit notification information through a device token of a receiver node to receive notification information.

In addition, the notification node 400 is provided as a server and can transmit notification information to each node 100 or 200 such as a mobile device.

5 is a flowchart for explaining a data transmission and access control method in a data transmission and access control system according to an embodiment of the present invention, and FIG. 6 is a flowchart for explaining the data transmission and access control method of FIG. 5 in more detail. As a flowchart, since the data transmission and access control method according to an embodiment of the present invention proceeds on substantially the same configuration as the data transmission and access control system 10 shown in FIG. 1, the data transmission and access control system of FIG. The same reference numerals are given to the same components as (10), and repeated descriptions will be omitted.

The data transmission and access control method of the present invention includes the steps of receiving a keyword (S110), identifying a transmission node (S130), establishing a P2P session (S150), and transmitting data to be shared (S170). and receiving sharing target data (S190).

Receiving a keyword (S110) may be a step in which the relay node 300 receives a keyword for sharing target data from the reception node 200.

The step of checking the transmitting node (S130) may be a step in which the relay node 300 checks the transmitting node 100 that provides sharing target data corresponding to the keyword.

Establishing the P2P session (S150) may be a step in which the relay node 300 establishes a P2P session between the receiving node 200 and the transmitting node 100.

The step of transmitting the data to be shared ( S170 ) may be a step in which the transmission node 100 transmits the data to be shared to the receiving node 200 through a chat window.

Receiving the data to be shared (S190) may be a step in which the reception node 200 receives the data to be shared through a chat window.

Hereinafter, a data transmission and access control method will be described in more detail with reference to FIG. 6 .

First, the relay node 300 may receive a keyword for data to be shared from the receiving node 200 (S215).

In addition, before the step of receiving the keyword (S215), the transmission node 100 creates a smart contract (SC) including a file contract (FC) related to the data to be shared and a user contract (UC) related to the transmission node 100. It can be created (S210).

At this time, the file contract (FC) may include metadata (File info.) and file transmission/reception log information (File send/Receive Info) of data to be shared.

And the user contract (UC) may include the Peer ID of the sending node 100, the Service ID, and encrypted password information for logging in to the blockchain network (BN). there is.

Thereafter, the relay node 300 may search for a smart contract (SC) corresponding to the keyword (S220).

Further, the relay node 300 may transmit the service ID of the sending node 100 included in the searched smart contract (SC) to the receiving node 200 (S225).

Thereafter, the relay node 300 may establish a P2P session between the receiving node 200 and the transmitting node 100 (S240).

In addition, the receiving node 200 may log in anonymously to the data transmission service through the connection window including the service ID of the searched smart contract (SC) (S230).

Thereafter, the relay node 300 may check peer IDs of the transmitting node 100 and the receiving node 200 (S235).

Then, the relay node 300 may establish a P2P session between the transmitting node 100 and the receiving node 200 (S240).

Thereafter, the transmitting node 100 may transmit the data to be shared to the receiving node 200 (S250).

In the step of transmitting the data to be shared ( S250 ), the transmission node 100 may transmit the data to be shared to the reception node 200 to which the P2P session is established through a chat window.

In addition, in the step of transmitting the data to be shared (S250), the file send/receive log information (File send/receive Info) of the smart contract (SC) can be updated (S255).

Also, the receiving node 200 may receive data to be shared.

In addition, the data transmission and access control system 10 of the present invention may further include a known node 400 constituting a blockchain network.

If the system 10 further includes the announcing node 400, the data transmission and access control method is a notification for announcing the establishment of the P2P session after the announcing node 400 establishes the P2P session (S240). Generating information and transmitting notification information to at least one of the transmission node 100 and the reception node 200 (S245) may be further included.

The data transmission and access control method of the present invention can be implemented in the form of program instructions that can be executed through various computer components and recorded on a computer-readable recording medium. The computer readable recording medium may include program instructions, data files, data structures, etc. alone or in combination.

Program instructions recorded on the computer-readable recording medium may be specially designed and configured for the present invention, or may be known and usable to those skilled in the art of computer software.

Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical recording media such as CD-ROMs and DVDs, and magneto-optical media such as floptical disks. media), and hardware devices specially configured to store and execute program instructions, such as 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 or the like as well as machine language codes such as those produced by a compiler. The hardware device may be configured to act as one or more software modules to perform processing according to the present invention and vice versa.

Although various embodiments of the present invention have been shown and described above, the present invention is not limited to the specific embodiments described above, and is commonly used in the technical field to which the present invention pertains without departing from the gist of the present invention claimed in the claims. Of course, various modifications are possible by those with knowledge of, and these modifications should not be individually understood from the technical spirit or prospect of the present invention.

10: data transmission and access control system 100: transmission node
200: receiving node 300: relay node
400: Announcement Node BN: Blockchain Network
SC: Smart Contract FC: File Contract
UC: User Contract

Claims (13)

In a data transmission and access control system that provides data transmission service based on a blockchain network,
a transmission node that transmits data to be shared;
a receiving node receiving the sharing target data; and
A relay node that receives a keyword for the sharing target data from the receiving node, checks the transmitting node that provides the sharing target data corresponding to the keyword, and establishes a P2P session between the receiving node and the transmitting node. include,
The receiving node, the transmitting node, and the relay node are nodes constituting the blockchain network, characterized in that, data transmission and access control system. According to claim 1,
The sending node,
Create a smart contract including a file contract related to the data to be shared and a user contract related to the transmission node;
The file contract,
Including metadata and file transmission/reception log information of the sharing target data,
The user contract,
A data transmission and access control system, characterized in that it includes a peer ID of the sending node, a service ID, and encrypted password information for logging in to the blockchain network. According to claim 2,
The relay node,
A data transmission and access control system, characterized by searching for a smart contract corresponding to the keyword and transmitting the service ID of the searched smart contract to the receiving node. According to claim 3,
The receiving node,
Log in anonymously to the data transmission service through the access window containing the service ID of the searched smart contract;
The relay node,
Characterized in that the P2P session between the sending node and the receiving node is established by checking the peer IDs of the sending node and the receiving node. According to claim 4,
The sending node,
A data transmission and access control system, characterized in that for transmitting the data to be shared through a chat window to the receiving node where the P2P session is established, and updating file transmission and reception log information of the smart contract. According to claim 1,
When the relay node establishes the P2P session, further comprising a notifying node generating notification information for notifying establishment of the P2P session and transmitting the notification information to at least one of the transmitting node and the receiving node. characterized, data transmission and access control systems. A data transmission and access control method in a data transmission and access control system that provides data transmission service based on a blockchain network,
The data transmission and access control system,
Including a receiving node, a transmitting node and a relay node constituting the blockchain network,
receiving, by the relay node, a keyword for data to be shared from the receiving node;
checking, by the relay node, a transmission node providing the sharing target data corresponding to the keyword;
establishing, by the relay node, a P2P session between the receiving node and the transmitting node;
transmitting, by the transmission node, the sharing target data; and
A data transmission and access control method comprising the step of receiving the sharing target data by the receiving node. According to claim 7,
Generating, by the transmission node, a smart contract including a file contract related to the data to be shared and a user contract related to the transmission node;
The file contract,
Including metadata and file transmission/reception log information of the sharing target data,
The user contract,
Data transmission and access control method, characterized in that it includes a peer ID of the sending node, a service ID, and encrypted password information for logging in to the blockchain network. According to claim 8,
The step of identifying the sending node,
the relay node searching for the smart contract corresponding to the keyword;
Data transmission and access control method comprising the step of the relay node transmitting the service ID of the searched smart contract to the receiving node. According to claim 9,
The receiving node further comprises anonymously logging in to the data transmission service through a connection window including the service ID of the searched smart contract;
In the step of establishing the P2P session,
characterized in that the P2P session between the transmitting node and the receiving node is established by checking the peer IDs of the transmitting node and the receiving node. According to claim 10,
In the sending step,
Characterized in that the transmitting node transmits the sharing target data to the receiving node with which the P2P session is established through a chat window, and updates file transmission/reception log information of the smart contract. According to claim 7,
The data transmission and access control system,
Further comprising a notice node constituting the blockchain network,
Further comprising, after the announcing node establishing the P2P session, generating notification information for notifying establishment of the P2P session and transmitting the notification information to at least one of the transmitting node and the receiving node. Characterized in that, data transmission and access control method. A computer-readable recording medium on which a computer program for performing the data transmission and access control method according to claim 7 is recorded.

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