KR100564646B1 - Storage device for storing encoded multimedia file and method for playing the file - Google Patents

Abstract

The present invention relates to a storage device for storing an encrypted multimedia file and a method of reproducing the file. The present invention relates to a method for reproducing a multimedia file through a storage device by embedding a decryption key in a predetermined storage device in which the encrypted multimedia file is stored. The present invention relates to a storage device for storing an encrypted multimedia file which prevents unauthorized use of the multimedia file by downloading a decryption key for a duplicated multimedia file online and playing the multimedia file.

According to an embodiment of the present invention, a storage device for storing an encrypted multimedia file includes a storage unit for storing an encrypted multimedia file, authentication information, and a decryption key, and whether or not to authenticate an encrypted multimedia file to be output with reference to the authentication information. An authentication unit to inspect, a decryption unit to decrypt the encrypted multimedia file to be output according to the inspection result, and an output unit to output the decrypted multimedia file.

Encryption key, decryption key, storage device, symmetric key cryptosystem

Description

Storage device for storing encoded multimedia file and method for playing the file}

1 is a conceptual diagram illustrating the distribution of a multimedia file on offline according to an embodiment of the present invention.

2 is a conceptual diagram illustrating the distribution of a multimedia file online according to an embodiment of the present invention.

3 is a block diagram illustrating a memory device according to an exemplary embodiment of the present invention.

4 is a flowchart illustrating input of a multimedia file according to an embodiment of the present invention.

5 is a flowchart illustrating an output of a multimedia file according to an embodiment of the present invention.

<Explanation of symbols on main parts of the drawings>

310: input unit 320: command receiving unit

330: storage unit 340: authentication unit

350: decoding unit 360: output unit

The present invention relates to a storage device for storing an encrypted multimedia file and a method for reproducing the file. More particularly, the present invention relates to a multimedia file through a storage device by embedding a decryption key in a predetermined storage device in which the encrypted multimedia file is stored. A storage device for storing an encrypted multimedia file that prevents unauthorized use of the multimedia file by causing the user to play the multimedia file or downloading a decryption key for the duplicated multimedia file online to play the multimedia file. will be.

Common encryption techniques are classified into symmetric key cryptosystem and public key cryptosystem. A symmetric key cryptosystem is typically DES (Data Encryption Standard), which is characterized by the same key used for encrypting and decrypting data. Therefore, when the sender and the receiver exchange messages, they must exchange the encryption key through a secure channel. If the encryption key is exposed to the outside, the security of the data is not guaranteed.

The public key cryptosystem is a representative RSA (Rivest-Shamir-Adleman). The public key cryptosystem is an asymmetric system. The key used to decrypt data in the public key cryptosystem is called a decryption key. ) Is different from the key used to encrypt the data (hereinafter referred to as the encryption key). Therefore, an encryption key, also called a public-key, has no reason to be exchanged between a sender and a receiver over a secure channel, and the receiver can encrypt data using his or her private-key. Can be decrypted.

Public key cryptosystems are based on difficult computational problems caused by trapdoor one-way functions, which are easy to operate in one direction but nearly impossible in the opposite direction. Accordingly, the public key cryptosystem is not used for data encryption because of its slow operation speed, and is mainly used for key exchange or digital signature for symmetric cryptography.

The active digitization of records, movies, and publications, and file sharing services that are rapidly spreading through the Internet in recent years, have resulted in serious copyright infringement of copyrighted works. As a result, manufacturers or suppliers are trying to reduce the risk of unauthorized copying by encrypting and distributing digitized files.

In particular, in the case of recording and movie media, the degree is serious, and it is necessary to take measures in a way that is easily accessible to the general user.

The present invention allows a multimedia file to be played back through a storage device by embedding a decryption key in a predetermined storage device in which an encrypted multimedia file is stored, or to download a decryption key for a duplicated multimedia file online to play a multimedia file. Thus, the purpose is to prevent unauthorized use of the multimedia file.

Another object of the present invention is to provide a service for deleting and restoring multimedia data using a certificate embedded in a storage device.

The objects of the present invention are not limited to the above-mentioned objects, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, a storage device for storing an encrypted multimedia file according to an embodiment of the present invention includes a storage unit for storing an encrypted multimedia file, authentication information and decryption key, and encryption to be output with reference to the authentication information. And an authentication unit for checking whether the encrypted multimedia file is authenticated, a decryption unit for decrypting the encrypted multimedia file to be output according to the test result, and an output unit for outputting the decrypted multimedia file.

According to an embodiment of the present invention, a method of playing an encrypted multimedia file includes storing an encrypted multimedia file, authentication information, and a decryption key in a predetermined storage device, and outputting an encrypted multimedia file to be output with reference to the authentication information. Checking whether or not to authenticate, extracting a decryption key of the encrypted multimedia file to be output according to the authentication result, and decrypting the encrypted multimedia file to be output using the extracted decryption key And outputting the decrypted multimedia file.

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and those of ordinary skill in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

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

1 is a conceptual diagram illustrating the distribution of a multimedia file on offline according to an embodiment of the present invention.

The system for distributing multimedia files offline includes a manufacturer 110, a seller 120, and a user 130.

The manufacturer 110 is a company that manufactures a storage device proposed by the present invention, and serves to deliver the encrypted multimedia file and the storage device storing the decryption key to the vendor 120. The storage device stores an encrypted multimedia file and authentication information for reproduction or reproduction of the file. The authentication information includes a unique number, an effective time, a list of possible devices, and the like. A unique number is a unique number assigned to a storage device, and is composed of a manufacturer code and a file code. The manufacturer code is assigned to distinguish a general file, and the same code is assigned to all storage devices manufactured by the manufacturer. The file code is a unique code given to an encrypted multimedia file, and a unique decryption key exists and the decryption key can be used to decrypt the multimedia file. Here, the general file includes all files other than the encrypted multimedia file provided by the manufacturer 110. The valid time is defined as the time or number of times the multimedia file can be used. The list of possible devices defines a list of devices that can be operated in conjunction with the storage device. The devices include a PC, a PDA, a mobile phone, an MP3 player, a host MP3 player, and a player thereof. Therefore, the manufacturer 110 may encrypt the same multimedia file using different encryption keys, and produce authentication information differently.

The seller 120 sells the storage device received from the manufacturer 110 to the user 130. The user 130 may purchase a storage device having authentication information suitable for his or her taste from the vendor 120. For example, the user 130 may purchase a storage device that can be played back on a PC for an effective time of 10 hours or a storage device that can be played back and copied on all external devices with 15 valid times.

The user 130 may play a multimedia file by connecting to a PC, a PDA, a mobile phone, an MP3 player, and a host MP3 player. In this case, when playing a multimedia file by connecting to a PC, PDA, or mobile phone, the file may be played using a player application (eg, Windows Media Player) installed in the device, or may be played by executing its own player.

The storage device in which the multimedia file is stored preferably enables playback, duplication and deletion of the file. Therefore, the user 130 may play or duplicate files according to the authentication information or delete the file. When the free space is secured in the storage device, the user 130 does not provide the free space to the manufacturer 110. You can also save a regular file of). In addition, it is preferable to allow the user 130 to freely control the general file without going through an authentication step.

Encrypted multimedia files stored in the storage device can be duplicated. When copying, only encrypted multimedia files except the decryption key are duplicated. Therefore, when a user wants to play a multimedia file copied on a PC or the like, the user needs to authenticate and decrypt it, and a function thereof is provided online.

2 is a conceptual diagram illustrating the distribution of a multimedia file online according to an embodiment of the present invention.

The user 130 who purchased the storage device offline may delete and re-save the multimedia file stored at the time of initial purchase, or may store a new multimedia file. At this time, the multimedia file can be downloaded online, and a PC, PDA, mobile phone, etc. may be used as a medium for connecting online, and USB, IEEE 1394, RS-232, IrDA, PS2 and Parallel ports and the like can be used.

A system for distributing multimedia files online includes a content provider 210 and a user 220.

The content provider 210 serves to provide the multimedia file to the user 220 who wants to receive the multimedia file online. In addition, the content provider 210 may provide an additional service for the multimedia file to the user 220. The additional service includes fan club information, a schedule, and an image of the original author (eg, a celebrity such as a singer or a movie star). This includes.

The user 220 requests the content provider 210 to provide a multimedia file online. At this time, when the user 220 wants to receive the multimedia file stored in the initially purchased storage device, the content provider 210 confirms and provides it free of charge using the unique number stored in the storage device. However, when the user 220 wants to receive a new multimedia file, the content provider 210 requests payment for the cost, and when the payment is completed, transmits the encrypted multimedia file and the decryption key to the user 220. do.

The memory device may store a plurality of multimedia files. Therefore, when the user 220 wants to play a specific multimedia file, the storage device extracts a decryption key corresponding to a unique number specified in the header of the file, and decrypts and plays the multimedia file using the decryption key.

3 is a block diagram illustrating a memory device according to an exemplary embodiment of the present invention.

The storage device is a device having predetermined input / output means and storage means, such as a USB flash drive, an SD card, an XD card, a mini SD, and an RS MMC. MP3 players and mobile phones are also included in the storage device.

In the embodiment of the present invention, the memory device includes an input unit 310, a storage unit 330, an authentication unit 340, a decoding unit 350, an output unit 360, and a command receiving unit 320.

The input unit 310 serves to receive an encrypted multimedia file or a general file using a predetermined input means. Input means include a USB port, an IEEE 1394 port, an RS-232 serial port, an IrDA port, a PS2 port, a parallel port, and a card reader.

The storage unit 330 stores a file received from the input unit, and the storage unit 330 preferably uses a flash memory that is a nonvolatile memory. Therefore, the file stored in the storage unit 330 can be easily stored and deleted according to a user's command. When the storage unit 330 stores an encrypted multimedia file provided by the manufacturer 110 or the content provider 210, the storage unit 330 stores not only the multimedia file but also authentication information and a decryption key. It is desirable to restrict the user's access to prevent leakage of the decryption key.

The authenticator 340 performs an overall authentication check on the reproduction or duplication of the encrypted multimedia file stored in the storage 330. The authentication check is performed using the authentication information stored in the storage unit 330. The authentication information includes a unique number, an effective time, a list of possible devices, and the like for the reproduction or duplication of the encrypted multimedia file. The unique number for playback or duplication consists of the manufacturer code and file code. Here, the manufacturer code is information used to check whether the stored multimedia file is a file certified by the manufacturer 110, and all the storage devices proposed by the present invention have the same manufacturer code to distinguish it from a general file. . The file code is used to check whether a file to be reproduced or copied is an authenticated file, and a unique value is preferably set for each multimedia file. The effective time is a time at which the stored multimedia file can be played back or copied, and the user can purchase it according to the type. For example, the user may purchase content that can be played for 10 hours after the initial playback, content that can be played 5 times, or content that can be played and copied within 10 times. The list of reproducible or duplicated devices refers to a list of devices that can interoperate with the storage device proposed by the present invention to reproduce or duplicate multimedia files. The list includes a PC, PDA, mobile phone, MP3 player, host MP3 player, and itself. Player and the like.

After authenticating the authentication unit 340 determines that the user is authorized to play or copy, the authentication unit 340 extracts a decryption key for the corresponding multimedia file. Basically, the decryption key is installed at the time of manufacture. The storage unit 330 may store not only the multimedia file initially stored, but also the multimedia file and decryption key to be downloaded from the content provider 210 later. Therefore, in response to the reproduction request of the multimedia file encrypted by the user, the authenticator 340 extracts a decryption key corresponding to the multimedia file, and transmits the decryption key to the decryption unit 350.

The decryption unit 350 decrypts the encrypted multimedia file using the decryption key received from the authentication unit 340, and transmits the decrypted multimedia file to the output unit 360. In this case, it is preferable to apply a symmetric key cryptography system which is faster in computing and decrypting multimedia files than asymmetric cryptography system. In addition, the decryption step is performed when the encrypted multimedia file is played, but the decryption step is preferably not performed during copying to prevent unauthorized distribution of the original multimedia file.

The output unit 360 serves to output the decrypted multimedia file or the encrypted multimedia file received from the decoder 350. At this time, the output means the output of the decrypted multimedia file for reproduction and the output of the encrypted multimedia file for duplication.

In addition, the output unit 360 may have its own multimedia file playback function to play the decoded multimedia file received from the decoder 350.

The command receiving unit 320 serves to receive commands such as reproduction, duplication, and deletion received from a user. The command received by the command receiver 320 is transferred to the authentication unit 340, and the authentication unit 340 passes through an authentication step according to the command and processes the corresponding multimedia file.

For reference, it is preferable to insert the unique number in the header of the multimedia file to perform the authentication step of the authentication unit 340 for the corresponding multimedia file.

4 is a flowchart illustrating input of a multimedia file according to an embodiment of the present invention.

The user 220 may store a multimedia file provided by the content provider 210 online in a storage device or may download and store a general file in association with a PC, a PDA, a mobile phone, and other storage devices while offline.

The storage device downloads a file according to a user's command (S410), examines the file header, and checks whether it is an encrypted multimedia file (S420). In this case, it is not simply an encrypted multimedia file provided by the content provider 210, but an encrypted multimedia file including a decryption key. This is because the user may store the encrypted multimedia file at his / her own device in a device such as a PC and then move it back to the storage device. In this case, the decryption key is not stored when the encrypted multimedia file is stored in the PC. . Therefore, the content provider 210 inserts a flag indicating whether the decryption key is attached to the encrypted multimedia file header to enable the storage device to determine whether a decryption key is present for the multimedia file to be downloaded. At this time, the storage device preferably removes a flag indicating whether a decryption key is attached, that is, stores authentication information, a multimedia file, and a decryption key.

If it is not an encrypted multimedia file including a decryption key, the storage device regards it as a simple general file (S430) and checks whether it is an authenticated file (S440). The authenticated file check can be performed by comparing the unique number of the multimedia file stored in the storage device. If there is a match among the stored unique numbers, it is a certified multimedia file, otherwise it can be determined as an unauthorized multimedia file. Thus, if it is determined as an authenticated multimedia file, the multimedia file and the decryption key are stored, and if it is determined that the multimedia file is not authenticated, a payment request is received from the content provider 210 (S450). Then, it checks whether the payment is completed (S460). When the payment is completed, the file and the decryption key are downloaded and stored (S470).

5 is a flowchart illustrating an output of a multimedia file according to an embodiment of the present invention.

The output of the multimedia file by the storage device means that the file is delivered to an external device of the storage device for reproduction or reproduction. In this case, the playback means that a sound or a video is output by a multimedia player such as a window media player installed in an external device by decrypting an encrypted multimedia file, and the copying is a device having a predetermined storage means connected to a storage device. It means to transmit encrypted multimedia file to PC (PDA, mobile phone, etc.). Therefore, when playing a multimedia file encrypted by an external device, a decryption step is required, and when copying, it is preferable that a decryption step is not performed in order to prevent unauthorized distribution of the original multimedia file.

When the storage device receives a request for outputting a file stored therein, the storage device checks whether the file is an encrypted multimedia file or a general file (S510). This can be obtained by examining the manufacturer code of the unique number specified in the header of the file. Thus, if the manufacturer code of the unique number does not match, it is regarded as a normal file and the file is output (S600). If the manufacturer code matches, the process proceeds to the next step. First, the unique number of the multimedia file is compared with the unique number of the multimedia file (S520), which checks whether the user has the decryption key for the file. This can be done by comparing the file code of the unique number with the file code of the decryption key it has. At this time, if the file codes do not match, the payment request is received from the content provider 210. After confirming the payment (S530), the payment proceeds to the next step and the payment ends when the payment is canceled.

When the file code matches or the payment is completed, the valid time check is performed (S540). Thus, if the valid time or number of times remain, go to the next step, otherwise you will receive a payment request from the content provider, check whether the payment (S550), if the payment is completed, go to the next step, and cancel the payment ends do.

If the valid time or number of times remain or the payment is completed, the device is checked (S560). In this case, it is checked whether the device connected to the current storage device and the interoperable device is an authenticated device. In addition, after checking the payment (S570), when the payment is completed, the process proceeds to the next step and terminates when the payment is canceled.

As described above, in order to prevent unauthorized distribution of the multimedia file, it is preferable not to decrypt the file during duplication. Therefore, it is checked whether the user's output command for the file for which the authentication check is completed is reproduction or duplication (S580). (S600) If it is a duplicate, it outputs without decrypting (S600).

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

According to the storage device for storing the encrypted multimedia file of the present invention as described above and the method of reproducing the file, one or more of the following effects are provided.

First, by embedding a decryption key in a predetermined storage device storing encrypted multimedia files to play the multimedia file through the storage device, or by downloading the decryption key for the duplicated multimedia file online to play the multimedia file. This has the advantage of preventing unauthorized use of multimedia files.

Second, there is an advantage that the storage device can be used for various purposes by providing a service for deleting and restoring multimedia data using a certificate embedded in the storage device.

Claims (9)

Authentication for the encrypted multimedia file comprising (a) an encrypted multimedia file, (b) a normal file, (c) a decryption key for the encrypted multimedia file, and (d) a manufacturer code and (e) a file code A storage unit for storing information; When the output of the stored file is requested, referring to (d) the manufacturer code, it is checked whether the file to be output is the (a) encrypted multimedia file or (b) the general file, and the output file is the (a) (E) an authentication unit extracting a decryption key for the encrypted multimedia file with reference to the (e) file code in case of an encrypted multimedia file; (C) decrypt the encrypted multimedia file using the decryption key if the requested output is a playback output; decrypt (a) the encrypted multimedia file if the requested output is a duplicate output. Decoding unit does not perform; And Storing an encrypted multimedia file including an output unit for selectively outputting at least one of the decrypted multimedia file, the undecrypted (a) encrypted multimedia file, and (b) a general file according to the output request store. The method of claim 1, And the output unit stores the decrypted multimedia file and the encrypted multimedia file for outputting or outputting the undecrypted (a) encrypted multimedia file according to a preset valid time. The method of claim 2, And the output unit stores an encrypted multimedia file outputting the decrypted multimedia file and the undecrypted (a) encrypted multimedia file when the payment for the payment request according to the output is completed. (1) if a request for output of the stored file is requested, determining whether the file to be output is (a) an encrypted multimedia file or (b) a general file by referring to a predetermined (d) manufacturer code stored corresponding to the file. ; (2) when the file to be output is the (a) encrypted multimedia file, (c) the encrypted multimedia file with reference to a predetermined (e) file code stored corresponding to the (a) encrypted multimedia file. Extracting a decryption key; (3) selectively performing (c) decrypting the encrypted multimedia file using the decryption key according to whether the requested output is a reproduction output or a duplicate output; And (4) at least one of the multimedia file decrypted according to the selection of step (3), the (a) encrypted multimedia file not decrypted according to the selection of step (3), and (b) the general file; Selectively outputting according to the requested output. The method of claim 4, wherein And (4) outputting or suspending output of the decrypted multimedia file and the undecrypted (a) encrypted multimedia file according to a preset valid time. The method of claim 5, The step (4) includes the step of outputting the decrypted multimedia file and the undecrypted (a) encrypted multimedia file when the payment for the payment request according to the output is completed. How to play. delete delete The method of claim 4, wherein (C) the decryption key is a decryption key downloaded over the Internet.

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