KR20100059185A - System and method for transferring encrypted document - Google Patents

Abstract

The present invention relates to a security file sending system and method, wherein when a security file attachment is requested while a mail sending program is driven, the security file is uploaded to a mail sending control server, and the mail sending control server sends the first communication. If the terminal user is an allowed user, the security file is stored, and a URL for the security file is generated and transmitted to the first communication terminal, and the first communication terminal receives a mail in which the received URL is inserted into the body. Generate and send to the second communication terminal, and when the mail transmission control server is requested to download a file from the second communication terminal, the file is allowed to be downloaded and the second communication terminal user is a decoded file download target. A security wave stored in a server, the decrypted security file being provided to the second communication terminal Since the work is stored in an encrypted state and the encrypted file is decrypted and provided according to whether or not the decrypted file is downloaded, the possibility of information leakage can be minimized even for malicious access inside and outside.

Mail, secure file, decryption, encryption

Description

System and Method for transferring encrypted document

The present invention relates to a secure file sending system and method, and more particularly, when a security file requested to be attached to an e-mail is a predetermined file type and the user is a user to which access rights are allowed, the first communication terminal secures the security. Request upload of a file to the mail sending control server, and if the mail sending control server is a user who is allowed to use the first communication terminal user, store the security file, generate a URL for the security file, and send it to the first communication terminal. The first communication terminal generates the mail in which the received URL is inserted into the body, and sends the mail to the second communication terminal. When the mail transmission control server requests a file download from the second communication terminal, If the file is allowed to download and the second communication terminal user is the target of downloading the decrypted file, the corresponding security file is decrypted. It relates to a security system and a system for sending files provided to the second communication terminal.

In general, an e-mail that transmits a predetermined text file through the Internet can not only be transmitted within a short time, but also various types of files can be transmitted together with the text, which is very convenient to use, and its use is generalized.

The e-mail transmission system for transmitting and receiving such e-mails uses an e-mail server that allows the user to access the Internet terminal, for example, a personal computer. The e-mail server is provided with a memory for storing e-mails. After connecting, you can read the email stored in the server's memory or send the email to another email server.

Since the email transmission service can attach and transmit various types of files together as described above, it also has the disadvantage of easily leaking information requiring security. This disadvantage can be a serious problem for businesses.

Moreover, the e-mail transmission system built around a conventional enterprise cannot check the contents of the e-mail or the information attached to the e-mail before the e-mail is sent. That is, since the contents of the e-mail can be checked after the e-mail is completed, post-processing is possible after the information necessary for security is leaked, but the leakage of the information requiring security cannot be prevented.

Recently, a service for uploading a large amount of data to an arbitrary server on the web has been provided. However, such a service also has a problem in that security data of an enterprise may be easily leaked even when used in an enterprise. If the upload service is provided by the enterprise, the email transmission system is used.

Therefore, there is a need for a method and system for sending e-mail that can prevent the leakage of information requiring security.

In addition, due to the strengthening of internal information security policy of the company, it is necessary to take measures to collaborate (document delivery and mutual editing) with existing external companies (public offices, BP, CP) by collecting the right to release self-written security documents granted to members. It became. In order to solve this problem, we tried to maintain the continuity of work by granting the recommendation to use the external file transfer file function of document security and the force release of the team security document (team leader authority). However, the following problems occurred. Here, the external transmission security file is delivered to an external user in the form of an executable file so that the security document can be viewed from the outside. When the external user clicks the external transmission security file, the external document can be read and output without installing a separate document security client. It is possible.

However, due to the filtering of EXE extensions in the mail server, many mails containing malicious code are being sent, and the EXE extension in EXE and ZIP files is also scanned and blocked due to the enhanced filtering technology for blocking them in each mail system.

In addition, a malfunction of an application not supported by the document security program occurs. That is, the external file security file could not be opened in the upper version of the Viewer which Open Office and document security do not support.

In addition, an application program conflict problem occurred according to the user PC environment. In other words, unless your PC is installed with various programs and does not have specialized PC knowledge, it is highly likely to infect Ad-ware and Virus, and in some cases, specific program information may be broken. In the case of an external transmission security file that operates by reading, there is a high possibility of malfunction.

In addition, it is possible to read and output contents for security, but it is impossible to edit and support mutual editing work.

In addition, due to the addition of the unit-level security file forced release authority addition, the work load of the unit-level forced release authority is generated. In other words, departments that have a lot of collaborations with external companies on the team's work have a lot of document exchanges, and in many cases, the security release request is made to the forced release authority.

In addition, there was a difficulty in reviewing the release criteria, security, etc. when the team needed to release security documents.

In addition, the distribution of distribution via e-mail is high in the distribution path of adware and viruses, and the filtering technology of the mail system has been strengthened to block it. For this reason, it is necessary to pass mail system filtering of normal business files.

In addition, the original function of the external transmission security file is a function to prevent the recipient from editing and storing the document arbitrarily when sending an important document to the outside. none.

An object of the present invention is to provide a secure file sending system and method that can deliver a secure document as a general document regardless of the filtering of the mail server program.

Another object of the present invention is to provide a security file sending system and method for expanding the productivity of the forced release authority by reducing the security document release task of the forced release authority for each team.

It is still another object of the present invention to provide a secure file sending system and method capable of unifying external business mail sending windows to enable user management and post management of a document distribution path.

It is still another object of the present invention to provide a secure file sending system and method for blocking attachment of files other than the file type designated by an administrator.

It is still another object of the present invention to provide a security file sending system and method in which only a user who is allowed to access a security file can attach a security file to an e-mail.

It is still another object of the present invention to provide a security file sending system and method for storing a security file stored in a server in an encrypted state and decrypting and providing an encrypted file according to whether the decrypted file is downloaded.

According to an aspect of the present invention to achieve the above object, if a security file attachment is requested in the state that the mail sending program is running, upload the security file to the mail sending control server, and transmitted from the mail sending control server A first communication terminal requesting shipment by inserting a URL of a security file into a mail body; and when a security file is uploaded from the first communication terminal, it is determined whether the first communication terminal user is an allowed user, and if the user is allowed, A mail sending control server which stores a security file to generate a URL for the security file, and transmits the generated URL to the first communication terminal, and a URL is inserted into a mail body according to a mail sending request of the first communication terminal. If a URL is selected from the mail server for sending the mail and the body of the mail sent from the mail server, the mail server is sent to the mail dispatch control server. Requesting the download file is sent security system including a first communication terminal to download the file is provided.

When a file download request is requested from the second communication terminal, the mail sending control server decrypts the corresponding security file by decrypting the corresponding security file when the file is allowed to be downloaded and the user of the second communication terminal is a download target of the decrypted file. To provide.

The first communication terminal determines whether the security file requested to be attached is a predetermined file type and whether the first communication terminal user is a user who is allowed to access the secure file. If the user is a registered user, the security file is uploaded to the mail delivery control server.

According to another aspect of the present invention, a communication unit for communication with a mail sending control server or a mail server, a user interface unit for receiving a user command, and a security file attachment when a security file attachment is requested while a mail sending program is running, A mail transmission control module uploading the mail transmission control server and requesting mail transmission by inserting a URL of a security file transmitted from the mail transmission control server into a mail body, and when a URL is selected from the mail body transmitted from the mail server, A communication terminal including a mail reception control module for accessing the mail sending control server and requesting and receiving a download of a corresponding file is provided.

The mail transmission control module, when a security file attachment is requested in a mail sending environment, checks whether the security file corresponds to a predetermined file type. Security file access authority check unit for determining whether the user is permitted to access the file, if the determination result of the security file access authority check unit, if the user is allowed, upload the security file to the mail sending control server to the security file A file upload control unit for receiving a URL for the URL, and a sending mail generating unit for generating a mail in which the URL received by the file upload control unit is inserted into the mail body.

The sending mail generating unit may convert and insert the URL inserted into the mail body into HTML.

The file filtering unit determines whether a file type corresponds to a predetermined file type by using an extension of an attached file.

The mail reception control module receives a mail including a secure document URL from the mail server, and when a URL included in the received mail body is selected by a user, the mail reception control module connects to the mail transmission control server to determine a corresponding file. It may include a file download unit for requesting and receiving a download.

According to another aspect of the present invention, a communication unit for communicating with a communication terminal, a database in which at least one of user information, file information, and log information is stored, and a security file upload is requested from the communication terminal, An upload control unit for determining whether the user is a user and controlling uploading of the security file according to the determination result, and if the user is permitted as a result of the determination of the upload control unit, storing the security file, generating a URL for the security file, and generating the URL A URL generation unit for transmitting a file to the terminal, when a file download is requested from the communication terminal, a download control unit for determining whether the communication terminal user is an authorized user for a download period of the corresponding file and controlling file download according to the determination result; As a result of the determination by the download control unit, the authenticated user is decrypted. When the file is to be downloaded, a mail sending control server including a decryption unit which decrypts an encrypted security file and provides the same to the communication terminal is provided.

The mail sending control server may further include an environment setting unit that adjusts at least one of a download permission period, an upload capacity, an upload permission extension, and a decryption permission IP setting.

The mail sending control server may further include a log information manager which stores outgoing log information by uploading a file and download log information by downloading a file in the database.

The upload control unit receives a security file and user information from the communication terminal according to a security file upload request, and determines whether the received user information is an allowed user by determining whether the received user information is a user registered in the database.

The download control unit examines the IP of the communication terminal to determine whether the user is an allowed user and whether the decrypted file is a download target.

According to another aspect of the present invention, if the first communication terminal is requested to attach a security file in the mail sending environment, the step of uploading the security file to the mail sending control server, the mail sending control server of the first communication terminal Determining, according to the security file upload request, whether the first communication terminal user is an allowed user, storing the security file if the user is an allowed user, generating a URL for the security file, and transmitting the generated security file to the first communication terminal. And generating, by the first communication terminal, a mail having a URL of a security file received from a mail sending control server inserted into a body, and sending a mail sending request message to a mail server, (d) the mail server sending the mail. Provided is a secure file sending method comprising the step of sending said mail to a second communication terminal based on a message.

In the secure file sending method, the second communication terminal accesses the mail sending control server by requesting a file download by a URL included in the mail from the mail server, and the mail sending control server requests the download. It is a download permission period for, and if the second communication terminal user is an authenticated user may further comprise the step of transmitting the file to the second communication terminal.

According to another aspect of the present invention, in a method for sending a mail with a secure file attached to the communication terminal, (a) if a secure file attachment is requested in the mail sending environment to determine whether the security file is a predetermined file type; Step (b) In the case of the predetermined file type as a result of the determination in step (a), determining whether the communication terminal user is a user who is allowed to access the security file, (c) the step (b) (D) if a URL for the security file is received from the mail transmission control server, if the user is an allowed user, uploading the security file to the mail transmission control server; Provided is a secure file sending method of a communication terminal comprising the step of generating and transmitting to a mail server.

In the step (a), if the secure file attachment button is selected while the mail sending program is driven, displaying a file selection screen; and if the security file is selected through the file selection screen, the security file is previously designated. The method may include determining whether it is a kind.

If the determination result of step (a) is not a predetermined file type, the method may further include displaying a security file attachment impossible message.

If the determination result of step (b) is not an allowed user, the method may further include displaying a security file attach impossible message.

According to another aspect of the present invention, a communication terminal receives a file attached to an email, comprising the steps of: receiving a mail including a secure document URL from a mail server; When selected, a method for receiving a secure file of a communication terminal is provided, the method including requesting to download a corresponding file by accessing a mail sending control server and receiving a decrypted file from the mail sending control server.

According to still another aspect of the present invention, in a method in which a mail transmission control server controls the sending of a mail to which a security file is attached, when a security file upload is requested from a first communication terminal, the user of the first communication terminal is allowed. Determining whether the user is a user; if the user is an acceptable user, storing the security file, generating a URL for the security file, and transmitting the generated URL to the first communication terminal; and downloading the security file from the second communication terminal. Determining whether the file is within the allowable period by checking a download permission period of the file, if the result of the determination is within the allowable period, determining whether the second communication terminal user is an authenticated user; If the communication terminal user is an authenticated user, determining whether the user is a downloadable decrypted file, the determination If the subject the decoded file to download, by decoding the security file and the second is provided a security file sending control method of the control messages sent to the server comprises the step of providing to the communication terminal.

Because it maintains the state, it is effective to minimize the possibility of information leakage due to local storage after security document release.

In addition, there is an effect of increasing the work efficiency due to the reduction of the release work, an additional task of the forced release authority.

In addition, there is an effect that the work convenience due to the process shortening when delivering documents outside the work.

In addition, the email system environment used by the member can be customized so that the member can maintain the existing work environment as much as possible.

In addition, security management through the unification of external documents for security documents (internal departments) can be strengthened, and the audit and management of documents sent to external parties such as suppliers can be strengthened.

In addition, the documents released by the business need to be managed by the member directly to date, but the security release process is omitted by the present invention, so the amount of security documents released by the purpose of the work is reduced, external hacking or internal random Even access, important documents are stored in a secure file, minimizing the possibility of external leakage.

Also, the security document can be delivered as a general document regardless of the filtering of the mail server program.

In addition, since the security file stored in the server is stored in an encrypted state and decrypted and provided according to the decrypted file download target, it is possible to minimize the possibility of information leakage in the internal and external malicious access.

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

1 is a view showing a secure file sending system according to the present invention.

Referring to FIG. 1, a secure file sending system includes first and second communication terminals 100a and 100b, a mail sending control server 200, and a mail server 300 that send and receive a secure file via mail. .

The first communication terminal 100a is an originating terminal for sending a security file through mail, and refers to a wired terminal or a wireless terminal.

When the first communication terminal 100a is requested to attach a security file while the mail sending program is driven, the corresponding security file is a predetermined file type, and when the access permission is allowed, the first communication terminal 100a sends the security file to the mail sending control server ( Upload to the server 200, and when the URL for the security file is received from the mail transmission control server 200, the mail is inserted into the mail body to request mail transmission.

When the first communication terminal 100a receives a secure file upload and a URL to the mail transmission control server 200, all packet and file data generated when the secure file is attached are Hypertext Transfer Protocol over Secure Socket Layer (HTTPS). Use a communication method.

The second communication terminal 100b is a receiving terminal for receiving mail and refers to a wired terminal or a wireless terminal.

The second communication terminal 100b requests a file download to the mail sending control server 200 by the URL included in the mail from the mail server 300 and downloads the file. Here, although only one receiving terminal is represented as the second communication terminal, there may be a plurality of receiving terminals.

When the security file is uploaded from the first communication terminal 100a, the mail transmission control server 200 determines whether the first communication terminal user is an allowed user, and if the user is an allowed user, stores the security file by storing the security file. Generate a URL for and transmit the generated URL to the first communication terminal (100a).

In addition, when a file download is requested from the second communication terminal 100b, the mail transmission control server 200 downloads the file when the file is allowed to be downloaded and the second communication terminal user is an authenticated user. It is provided to the second communication terminal 100b.

When the mail transmission request is made from the first communication terminal 100a, the mail server 300 sends a mail in which a URL is inserted into the mail body to the second communication terminal 100b.

2 is a block diagram schematically showing the configuration of a communication terminal capable of sending and receiving mail according to the present invention.

Referring to FIG. 2, the communication terminal 100 capable of sending and receiving mail includes a communication unit 110 for communication with a mail sending control server or a mail server, a user interface unit 120 for receiving a user command, and mail sending. The program includes a storage unit 130, an output unit 140, a mail transmission control module 150 for controlling mail transmission, and a mail reception control module 160 for controlling mail reception.

The mail transmission control module 150 sends a security file to a mail transmission control server when a security file attachment is requested when a security file attachment is requested while the mail transmission program is driven, and the access permission is allowed. Uploading, and when the URL for the security file is received from the mail transmission control server, the mail is inserted by inserting the URL into a mail body.

The mail transmission control module 150 which performs the above role includes a file filtering unit 151, a secure file access authority checker 152, a file upload control unit 153, and an outgoing mail generation unit 154.

The file filtering unit 151 checks whether the security file corresponds to a predetermined file type when a security file attachment is requested in the mail sending environment. That is, the file filtering unit 151 determines whether the file type corresponds to a predetermined file type by using an extension of the attached file, and blocks file attachment when a file other than the specified file type is attempted to be attached.

The security file access authority checker 152 determines whether the user is a user who is allowed to access the security file when the file filtering unit 151 confirms that the file is a predetermined file type. In the case of a security file, the access authority is different for each user, and in order to distinguish the security file, an access authority checker 152 of a file attached to a security file attachment function is provided to block the transmission of the security file by an unauthorized user.

The file upload control unit 153 uploads the security file to the mail transmission control server when the security file access authority checker 152 determines that the user is allowed to receive the URL for the security file.

The sending mail generating unit 154 generates a mail in which the URL received by the file upload control unit 153 is inserted into the mail body. In this case, the sending mail generating unit 154 converts and inserts a URL inserted into the mail body into HTML (HyperText Markup Language).

Existing e-mail is also attached to the file in the mail was sent, but in the case of the present invention, since only the URL is added to the mail body is sent, the effect of reducing the mail capacity and improving the transmission speed is increased.

The URL format inserted in the body is inserted using HTML to avoid the filtering technique of the external mail server. In other words, images, objects, and figures inserted by Outlook 2007 are recognized as attached image files in certain mail systems, so they may not provide a single user interface (UI) to users depending on the mail system. If you use Script to avoid this, it is highly likely to be blocked by malicious or spam mails. Therefore, to build a single UI environment, build an image and other necessary data in the security file sending system, and then use the HTML form in the body of the mail. Regardless of the system, it is possible to provide a single UI to external companies that receive it.

When the mail reception control module 160 receives the mail including the secure document URL from the mail server, the mail reception control module 160 accesses the mail transmission control server by selecting the URL and requests and receives the download of the file.

The mail reception control module 160 performing the above role includes a mail reception unit 161 and a file download unit 162.

The mail receiving unit 161 receives a mail including a secure document URL from the mail server.

When the URL included in the received mail body is selected by the user, the file download unit 162 requests and downloads the file by accessing the mail transmission control server.

3 is a block diagram schematically showing the configuration of a mail sending control server according to the present invention.

Referring to FIG. 3, the mail sending control server 200 may include a communication unit 210, an upload controller 220, a URL generator 230, a download controller 240, and a decoder 250 for communication with a communication terminal. , Log information management unit 260, environment setting unit 270, and database 280.

The database 280 may include a user information database 282 storing user information authorized to use a mail sending control server, a file information database 284 storing a file uploaded from a communication terminal, outgoing log information by uploading a file, and And a log information database 286 in which download log information by downloading files is stored.

User information stored in the user information database 282 refers to an IP address, an email address, and the like.

Each file stored in the file information database 284 is mapped to user information uploading the file.

When the upload of the security file is requested from the communication terminal, the upload control unit 220 determines whether the communication terminal user is an allowed user, and controls the security file upload according to the determination result.

That is, the upload controller 220 receives the security file and the user information from the communication terminal according to the security file upload request, determines whether the received user information is a user registered in the database, and whether the user is an allowed user. Judge.

The URL generator 230 stores the security file if the user is an acceptable user as a result of the determination of the upload controller 220, generates a URL for the security file, and transmits the URL to the communication terminal. The URL generation unit 230 changes the file name to the serial number of the registered file, stores the file name, and transmits the stored file to the communication terminal.

When a file download is requested from the communication terminal, the download control unit 240 determines whether the communication terminal user is an authorized user during the download permission period for the file and controls file download according to the determination result.

That is, the download controller 240 examines the IP of the communication terminal to determine whether the user is an allowed user and whether the decrypted file is a download target. In other words, the download controller 240 determines whether the IP of the communication terminal is a decoded file download target by using the decryption allowable IP information set by the environment setting unit 270.

The decryption unit 250 decrypts the encrypted security file and provides the decryption file to the communication terminal when the user is an authenticated user and the target of the decrypted file download is determined by the download control unit 240.

The log information manager 260 stores the outgoing log information by uploading the file and the download log information by downloading the file in the database 286.

The environment setting unit 270 adjusts at least one of a download permission period, an upload capacity, an upload permission extension, and a decryption permission IP setting.

4 is a diagram illustrating a security file sending method according to the present invention.

Referring to FIG. 4, when the originating terminal runs a mail sending program (S400), when a security file attachment is requested to the mail to be sent (S402), it is determined whether the corresponding security file is a predetermined file type (S404). ).

If it is determined in step S404 that the file type is predetermined, the calling terminal determines whether the user is a user permitted to access the security file (S406).

As a result of the determination in S406, if the user is granted the access right, the calling terminal requests the upload of the security file to the mail transmission control server (S408).

Then, the mail sending control server determines whether the calling terminal user is an allowed user (S410).

If it is determined that the user is allowed in step S410, the mail transmission control server stores the security file to generate a URL for the security file (S412), and transmits the generated URL to the originating terminal (S414). .

Then, the originating terminal generates a mail in which the received URL is inserted into the body and transmits a mail sending request message to a mail server (S416).

The mail server transmits the mail to a receiving terminal based on the mail sending request message (S418).

The receiving terminal requests a file download by accessing the mail sending control server by the URL included in the mail from the mail server (S420).

Then, the mail transmission control server determines whether the download request period is the download request file (S422).

If it is determined in S422 that the download is allowed, the mail sending control server determines whether the receiving terminal user is an authenticated user (S424).

If it is determined that the user is an authenticated user, the mail sending control server transmits the file to the receiving terminal (S426).

If, as a result of the determination in S424, the user is not allowed, the mail transmission control server transmits a download impossible message to the receiving terminal (S428).

If it is determined in S422 that the download is not allowed, the mail transmission control server performs S428.

If, as a result of the determination in step S410, the user is not allowed, the mail sending control server transmits a mail sending impossible message to the calling terminal (S430).

If it is determined in S404 that the file type is not a predetermined file, the calling terminal outputs a secure file attachment impossible message (S432).

If it is determined in S406 that the user is not authorized to access the secure file, the calling terminal performs S432.

5 is a flowchart illustrating a method for sending a mail with a security file attached by a communication terminal according to the present invention.

Referring to FIG. 5, if the secure file attachment button is selected by the user (S502) while the mail sending program is driven (S500), the communication terminal displays a file selection screen (S504). The file selection screen may be output in the form of a pop-up and supports single or multiple selection of a security file.

When a security file is selected through the file selection screen (S505), the communication terminal determines whether the security file is a predetermined file type (S506).

If it is determined in step S506 that the file type is predetermined, the communication terminal determines whether the user of the communication terminal is allowed to access the security file (S508).

If the determination result of the step S508 is the allowed user, the communication terminal attaches the selected security file (S510), and if the send mail button is selected by the user (S512), the security file upload request to the mail transmission control server (S514).

When communicating with a mail sending control server every time a security file is attached, user inconvenience occurs when the URL of an attached file is added and deleted. When the user attaches the security file and designates the final mail sending process as the time of clicking the send button, when the user clicks the send button, the user randomly holds and uploads the security file attached by the user to the mail sending control server. .

At this time, regardless of the number of attached files, it is applied collectively. The above method has the advantage that the user can not arbitrarily manipulate the URL received from the mail transmission control server, and solves the problem of the existing additional deletion method in the additional file deletion management of the security file attachment.

After the execution of S514, if the URL for the security file is received from the mail transmission control server (S516), the communication terminal inserts the received URL into the mail body (S518), and the mail containing the URL is inserted. Create and transmit to the mail server (S520).

If it is determined in S506 that the file type is not a predetermined file, the communication terminal outputs a secure file attachment impossible message (S522).

In addition, if it is determined that the user in S508 is not an allowed user, the communication terminal performs the S522.

6 is a flowchart illustrating a method for receiving a file attached to a mail by a communication terminal according to the present invention.

Referring to FIG. 6, when a mail including a secure document URL is received from a mail server (S600), the communication terminal determines whether a URL included in the mail is selected by the user (S602).

If the URL is selected by the user as a result of the determination in S602, the communication terminal accesses the mail sending control server and requests the download of the corresponding file (S604).

The mail sending control server extracts the file according to the file download request of the communication terminal and transmits the file to the communication terminal.

Then, the communication terminal receives the file from the mail sending control server (S606). At this time, when the communication terminal user is the decrypted file download target, the communication terminal receives the decrypted file. If the communication terminal user is not the decrypted file download target, the communication terminal receives the security file as it is.

7 is a flowchart illustrating a method of controlling a mail sending control server according to the present invention to send mail with a secure file attached thereto.

Referring to FIG. 7, when a security file upload is requested from the first communication terminal (S700), the mail transmission control server determines whether the first communication terminal user is an allowed user (S702).

If it is determined in S702 that the user is permitted, the mail transmission control server stores the security file, generates a URL for the security file (S704), and transmits it to the first communication terminal (S706). The security file stored in the mail transmission control server is stored in an encrypted state, thereby minimizing the possibility of information leakage even inside and outside malicious access.

Thereafter, when a file download request is requested from the second communication terminal (S708), the mail transmission control server checks the download permission period of the file and determines whether the file is within the allowable period (S710).

If the result of the determination in S710 is within the download permission period, the mail transmission control server determines whether the second communication terminal user is an authenticated user (S712).

If it is determined that the user is an authenticated user in step S712, the mail transmission control server determines whether or not the user downloads the decrypted file (S714).

That is, since the decrypted file download target is set by the mail sending control server by IP, the mail sending control server may check whether the IP of the second terminal that requested the file download is the decrypted file download target.

If it is determined that the decrypted file is to be downloaded, the mail transmission control server decrypts the security file and provides the decrypted security file to the second communication terminal (S716).

If it is determined in S714 that the decrypted file is not a download target, the mail transmission control server transmits the security file as it is (S718).

If it is determined in S710 that the download period is not allowed, the mail transmission control server transmits a download disable message to the second communication terminal (S720).

If, as a result of the determination in S712, the user is not an allowed user, the mail transmission control server performs S720.

If, as a result of the determination in S702, the user is not an allowed user, the mail sending control server transmits a mail sending impossible message to the first communication terminal (S722).

As such, those skilled in the art will appreciate that the present invention can be implemented in other specific forms without changing the technical spirit or essential features thereof. Therefore, the above-described embodiments are to be understood as illustrative in all respects and not as restrictive. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

As described above, the secure file sending system and method according to the present invention stores the secure file in an encrypted state on the server, inserts the URL for the attached file into the mail body, and sends it, and decrypts the file by requesting the file download by the URL. It can be easily used for a technique of sending a secure file through an e-mail provided by decrypting an encrypted file according to whether to download.

1 is a view showing a secure file sending system according to the present invention.

Figure 2 is a block diagram schematically showing the configuration of a communication terminal capable of sending and receiving mail according to the present invention.

Figure 3 is a block diagram schematically showing the configuration of a mail sending control server according to the present invention.

4 is a diagram illustrating a security file sending method according to the present invention.

5 is a flowchart illustrating a method for sending a mail with a secure file attached to a communication terminal according to the present invention.

6 is a flowchart illustrating a method for receiving a file attached to a mail by a communication terminal according to the present invention.

7 is a flowchart illustrating a method of controlling a mail sending control server according to the present invention for sending mail with a secure file attached thereto.

<Explanation of symbols for the main parts of the drawings>

100: communication terminal 110, 210: communication unit

120: user interface unit 130: storage unit

140: output unit 150: mail transmission control module

151: File filtering unit 152: Secure file access permission check unit

153: file upload control unit 154: sending mail generation unit

160: mail receiving control module 161: mail receiving unit

162: File download unit 200: Mail sending control server

220: upload control unit 230: URL generation unit

240: download control unit 250: decryption unit

260: log information management unit 270: environment setting unit

280: Database 300: Mail Server

Claims (21)

Uploading the security file to the mail transmission control server when a security file attachment is requested while the mail sending program is running, and inserting the URL of the security file transmitted from the mail sending control server into the mail body to request sending; Communication terminal; When the security file is uploaded from the first communication terminal, it is determined whether the first communication terminal user is an allowed user, and if the allowed user is stored, the security file is stored to generate a URL for the security file, and the generated URL A mail sending control server transmitting to the first communication terminal; A mail server for sending a mail in which a URL is inserted into a mail body according to a mail sending request of the first communication terminal; and A second communication terminal for downloading a file by requesting a file download from the mail transmission control server when a URL is selected from a body of the mail transmitted from the mail server; Secure file sending system comprising a. The method of claim 1, When a file download request is requested from the second communication terminal, the mail sending control server decrypts the corresponding security file by decrypting the corresponding security file when the file is allowed to be downloaded and the user of the second communication terminal is a download target of the decrypted file. Secure file delivery system, characterized in that provided in. The method of claim 1, The first communication terminal determines whether the security file requested to be attached is a predetermined file type and whether the first communication terminal user is a user who is allowed to access the secure file. And uploading the security file to the mail delivery control server if the user is a registered user. A communication unit for communicating with a mail sending control server or a mail server; A user interface unit for receiving a user command; When a security file attachment is requested while the mail sending program is running, the security file is uploaded to the mail sending control server, and the mail requesting to send mail is inserted by inserting the URL of the security file sent from the mail sending control server into the mail body. Outgoing control module; and A mail reception control module for accessing the mail transmission control server and requesting and receiving a download of a corresponding file when a URL is selected from a mail body transmitted from the mail server; Communication terminal comprising a. The method of claim 4, wherein The mail transmission control module, A file filtering unit to check whether a security file corresponds to a predetermined file type when a security file attachment is requested in a mail sending environment; A security file access authority check unit for determining whether the user is a user who is permitted to access the security file when the file filtering unit is a predetermined file type; A file upload control unit for uploading the security file to a mail transmission control server and receiving a URL for the security file when the security file access authority checker determines that the user is allowed; And a sending mail generating unit generating a mail in which a URL received by the file upload controller is inserted into a mail body. The method of claim 5, The sending mail generating unit is a communication terminal, characterized in that for converting and inserting the URL inserted in the body of the mail to HTML. The method of claim 5, And the file filtering unit determines whether a file type corresponds to a predetermined file type using an extension of an attached file. The method of claim 4, wherein The mail reception control module, A mail receiver for receiving a mail including a secure document URL from the mail server; And a file download unit for accessing the mail transmission control server and requesting to download the corresponding file when the URL included in the received mail body is selected by the user. A communication unit for communicating with a communication terminal; A database storing at least one of user information, file information, and log information; An upload control unit for determining whether a communication terminal user is an allowed user and controlling a security file upload according to a result of the determination when a security file upload is requested from the communication terminal; A URL generation unit for storing the security file, generating a URL for the security file, and transmitting the generated security file to the communication terminal when the user is allowed in the upload controller; If a file download is requested from the communication terminal, a download control unit for determining whether the communication terminal user is an authenticated user and the user is an authorized user to download the file, and controls the file download according to the determination result; And A decrypting unit for decrypting an encrypted security file and providing the decrypted security file to the communication terminal when the user is an authenticated user and a target for downloading a decrypted file; Mail sending control server comprising a. 10. The method of claim 9, And an environment setting unit configured to adjust at least one of a download permission period, an upload capacity, an upload permission extension, and a decryption permission IP setting. 10. The method of claim 9, And a log information management unit which stores outgoing log information by uploading a file and download log information by downloading a file in the database. 10. The method of claim 9, The upload control unit receives a security file and user information from the communication terminal according to a security file upload request, and determines whether the received user information is an allowed user by determining whether the received user information is a user registered in the database. Mail control server. 10. The method of claim 9, The download control unit checks the IP of the communication terminal and determines whether it is an allowed user or not, and whether it is a decrypted file download object. Requesting the first communication terminal to upload the security file to the mail transmission control server when a security file attachment is requested in the mail sending environment; In response to the request for uploading a security file from the first communication terminal, the mail transmission control server determines whether the first communication terminal user is an allowed user, stores the corresponding security file if the user is an allowed user, and retrieves a URL for the security file. Generating and transmitting the generated information to the first communication terminal; Generating, by the first communication terminal, a mail in which a URL of a security file received from a mail sending control server is inserted into a body, and sending a mail sending request message to a mail server; and (d) the mail server transmitting the mail to a second communication terminal based on the mail sending request message; Security file sending method comprising a. The method of claim 14, Requesting, by the second communication terminal, to download the file by accessing the mail delivery control server by the URL included in the mail from the mail server; And transmitting the file to the second communication terminal when the mail transmission control server is a download permission period for the download requested file and the second communication terminal user is an authenticated user. In the communication terminal sends a mail with a security file attached, (a) determining whether the security file is a predetermined file type when a security file attachment is requested in the mail sending environment; (b) determining that the communication terminal user is a user who is allowed to access the security file if the file type is a predetermined file as a result of the determination of step (a); (c) requesting the security file to be uploaded to the mail transmission control server when the determination result of step (b) is an allowed user; and (d) when the URL for the security file is received from the mail transmission control server, generating a mail including the received URL and transmitting the mail to the mail server; Security file sending method of the communication terminal comprising a. The method of claim 16, In step (a), Displaying a file selection screen if a secure file attachment button is selected while the mail sending program is driven; If the security file is selected through the file selection screen, determining whether the security file is a predetermined file type; security file sending method of a communication terminal comprising a. The method of claim 16, If the result of the determination in step (a) is not a predetermined file type, security file sending method of the communication terminal further comprising the step of displaying a message not to attach a security file. The method of claim 16, If it is determined that the step (b) is not an allowed user, the method for sending a security file of the communication terminal further comprising the step of displaying a message that cannot attach the security file. In the communication terminal receives a file attached to the mail, Receiving a mail including a secure document URL from a mail server; If a URL included in the mail is selected by the user, accessing a mail sending control server and requesting a download of the file; and Receiving a decrypted file from the mail sending control server; Security file receiving method of a communication terminal comprising a. In the mail sending control server to control the sending of the mail with a secure file attached, If a security file upload is requested from the first communication terminal, determining whether the first communication terminal user is an allowed user; Storing the security file and generating a URL for the security file and transmitting the generated security file to the first communication terminal if the user is an acceptable user; When a secure file download is requested from the second communication terminal, determining whether the file is within an allowable period by checking a download allowance period of the corresponding file; Determining whether the second communication terminal user is an authenticated user when the determination result is within an allowable period; If the second communication terminal user is an authenticated user, determining whether the user is an object to download a decrypted file; and Decrypting the security file and providing the decrypted file to the second communication terminal when the decrypted file is to be downloaded; Security file sending control method of the mail sending control server comprising a.

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