JP5251111B2 - Image display system - Google Patents

Description

  The present invention relates to an image display system using electronic paper, and more particularly, to information leakage prevention technology when an image is transmitted to electronic paper.

  In mobile information terminals such as mobile phones, various techniques are known that complement the display screen size limitation. For example, Patent Document 1 discloses that an image such as so-called content displayed on a mobile phone is transmitted and displayed on electronic paper by infrared communication or the like.

JP 2006-157725 A

  By the way, the above-described Patent Document 1 does not disclose a technique for preventing information leakage of communication between an image transmission source such as a server device or a mobile phone and an image transmission destination such as electronic paper. There is a possibility that image information may be intercepted or wiretapped with a mobile phone.

  On the other hand, if various information relating to encryption or the like is added to image information in order to prevent information leakage, the communication efficiency is lowered. Furthermore, in a portable information terminal or the like, power consumption increases because the encrypted image information is decrypted. As a result, the mobile information terminal may need to be charged frequently.

  The present invention has been made in view of such circumstances, and provides an image display system that suppresses information leakage at the time of transmitting an image to electronic paper while suppressing a decrease in the storage capacity of the portable information terminal. The purpose is to do.

According to the first aspect of the present invention, an image is displayed on an electronic paper having an image display area and holding a written image, and a pair of different secret key information and public key information are respectively provided. a plurality of drive circuits assigned, constitute a memory circuit electronic paper identification information for identifying the electronic paper has been stored, each pair of said plurality of drive circuits, encrypted with the public key information has been image information anda plurality of decoding circuits for decoding by the secret key information, and transmits the electronic paper identification information and the public key information via the communication device to the server device, by the public key information Encrypted image information is received from the server device, the encrypted image information is decrypted by the plurality of decryption circuits, and the decrypted image information is decrypted by the electronic copy. And an electronic paper display control unit for displaying against par, and encrypted by the first common key information to aggregate the electronic paper identification information and the public key information received from the electronic paper display control unit, wherein It said communication device to be transmitted to the server device, a plurality of image information divided from one image information, wherein the first common key the public key information decoded by the information encrypted respectively, wherein a division origin one together the image information of the reproducible reproduction information, an image display system characterized by having, said server device to be transmitted to the electronic paper display control unit having the electronic paper identification information.

Each invention of claim 2 is the invention according to claim 1, wherein the reproduction information comprises a sequence information rearranged in a regular order, the server apparatus, the divided plurality of image information When encrypted and transmitted to the electronic paper display control unit, it is transmitted in a random order.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein the server device encrypts each of the divided pieces of image information and transmits the encrypted image information to the electronic paper display control unit. The reproduction information is added to the head of at least one of the divided pieces of image information and transmitted.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the server device and the electronic paper display control unit each store the second common key information, and the server device The reproduction information is encrypted with the second common key information, and the electronic paper is characterized by decrypting the reproduction information with its second common key information.

  The invention described in claim 5 is characterized in that, in the invention described in any one of claims 1 to 4, the identification information is information obtained by connecting a plurality of public key information.

  A sixth aspect of the invention is characterized in that, in the invention of any one of the first to fifth aspects, the decryption circuit is a circuit for decrypting the encryption by the stream cipher.

  According to the first aspect of the present invention, it is possible to suppress information leakage when an image is transmitted to the electronic paper display control unit while suppressing a decrease in the storage capacity of the portable information terminal.

  According to the invention described in claim 2, the suppression of information leakage is enhanced as compared with the case where the present configuration is not provided.

  According to the third aspect of the present invention, the waiting time for image display in the electronic paper is reduced as compared with the case where the present configuration is not provided.

  According to the fourth aspect of the present invention, information leakage of image information in communication between the server device and the electronic paper display control unit is suppressed as compared with the case where the present configuration is not provided.

  According to the fifth aspect of the present invention, information leakage of identification information is suppressed as compared with the case where the present configuration is not provided.

  According to the invention described in claim 6, the scale of the decoding circuit is reduced as compared with the restoration by software.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of an image display system according to the first embodiment.

As shown in FIG. 1, the image display system includes a communication device 10, a mobile phone 20, a server device 30, an electronic paper display control unit 40, an electronic paper 41, and the like. As shown in the figure, identification information and a plurality of public key information (indicated as a public key group in the figure) possessed by the electronic paper display control unit 40 are transmitted to the server device 30 via the communication device 10 and the mobile phone 20. Then, the server device 30 encrypts the image information to be transmitted based on the transmission request from the mobile phone 20 with the public key information, and transmits the encrypted image information to the electronic paper display control unit 40 via the mobile phone 20.
In addition, when the electronic paper 41 is removable from the electronic paper display control unit 40 and identification information is given to the electronic paper 41 itself, the electronic paper 41 is connected to the electronic paper display control unit 40. The electronic paper display control unit 40 reads identification information from the electronic paper 41 through a short-range wireless connection such as wired or RFID, stores the identification information in the storage unit 12 of the electronic paper display control unit 40, and is transmitted to the server device 30. The

  Subsequently, each device except the above-described mobile phone 20 will be described with reference to the drawings. Note that the mobile phone 20 as a portable information terminal is not an indispensable constituent requirement, and the communication device 10 and the server device 30 may directly communicate with each other, but by including the mobile phone 20 in the image display system, Long-distance communication between the communication device 10 and the server device 30 becomes possible.

First, the communication device 10 will be described with reference to FIG.
As shown in FIG. 2, the communication device 10 includes a communication unit 11, a storage unit 12, an encryption unit 13, a control unit 14, a battery (not shown), and the like.

  The communication unit 11 includes, for example, an antenna, and transmits and receives various types of information to and from an electronic paper display control unit and a mobile phone by radio communication using radio waves. Instead of the antenna, it may be composed of a light emitting element or a light receiving element, and communicated by wireless communication such as Bluetooth (registered trademark) or IrDA (Infrared Data Association). Also good. The communication form may be not only wireless communication but also wired communication such as a cable or a cord. In this case, a USB (Universal Serial Bus) connection or the like may be used.

  The storage unit 12 is configured by a RAM (Random Access Memory), a ROM (Read Only Memory), or the like, and stores identification information and public key information received via the communication unit 11, and various kinds of encryption necessary for encryption described later. Memorize the program. Examples of RAM include SRAM (Static RAM), DRAM (Dynamic RAM), SDRAM (Synchronous DRAM), and NVRAM (Non Volatile RAM). ROM includes, for example, flash memory. In addition, the first common key information for encrypting the identification information and the like when communicating with the server device 30 is also stored. Note that the first common key information may be stored in advance by an administrator or the like who manages the communication device 10.

  The encryption unit 13 aggregates and encrypts the identification information and the plurality of public key information. Encryption is performed by, for example, DES (Data Encryption Standard), Triple DES, AES (Advanced Encryption Standard), or the like. When the encryption of the identification information or the like is completed, the encryption unit 13 transmits this to the communication unit 12.

  The control unit 14 is configured by a CPU, and comprehensively controls the communication unit 11, the storage unit 12, the encryption unit 13, and the like. The control unit 14 receives power supplied from the battery, extracts a required program stored in the ROM, and executes various processes such as encryption and transmission / reception of identification information. For example, a solar battery may be used as the battery. The required program may be a program according to a flowchart described later.

  From the viewpoint of portability, the size of the communication device 10 is preferably, for example, about the size of a passport, a business card, or an employee ID card, and is preferably made of a resin material such as plastic from the viewpoint of weight reduction. Thus, by separating the communication device 10 from the mobile phone 20 and making it a separate body, it is not necessary to perform processing such as encryption on the mobile phone 20, and a reduction in the storage capacity of the mobile phone 20 is suppressed. Further, a lamp or the like indicating the charging capacity may be formed in the communication device 10 so that the user can visually recognize the remaining approximate operating time.

Next, the server device 30 will be described with reference to FIG.
As shown in FIG. 3, the server device 30 includes a communication unit 31, a storage unit 32, an image information division unit 33, an encryption unit 34, an array information generation unit 35, a control unit 36, and the like.

  The communication unit 31 includes, for example, an antenna, and transmits and receives various information to and from the mobile phone 20 and the like by radio communication using radio waves. Similar to the communication unit 11, a cable connection using a USB connection may be used.

  The storage unit 32 includes a RAM, a ROM, and the like, and stores identification information and public key information received via the communication unit 31, stores image information to be transmitted, and divides and encrypts image information to be described later. It stores various programs necessary for generating data and generating sequence information. The RAM and ROM described above can be used. In addition, the first common key information for decrypting the identification information and the like when performing communication with the communication device 10 and the second sequence information for encrypting later-described sequence information necessary for performing communication with the electronic paper 40. 2 common key information is also stored. Note that the first common key information and the second common key information may be stored in advance by an administrator who manages the server device 30 or the like.

  The image information dividing unit 33 divides image information to be transmitted based on a transmission request from the mobile phone 20. The division form is desirably matched to the matrix display form of the electronic paper 41.

  The encryption unit 34 encrypts the divided image information based on the public key information. In addition, based on the second common key information, sequence information to be described later is encrypted. As an encryption algorithm, for example, DES, AES, RSA, MD5, SHA-1, HMAC-MD5, UMAC2 / 8, elliptic curve cryptosystem, or the like can be used. Techniques such as stream ciphers may be used.

  The array information generation unit 35 randomly rearranges a plurality of encrypted image information, and generates array information as reproduction information for rearranging the rearranged image information in the original order. The array information generation unit 35 adds the array information to the image information.

  The control unit 36 is composed of a CPU, and comprehensively controls the communication unit 31, the storage unit 32, the image information division unit 33, the encryption unit 34, the array information generation unit 35, and the like. The control unit 34 receives power supply from the battery, extracts a required program stored in the ROM, and executes various processes such as encryption and transmission / reception of image information. The required program may be a program according to a flowchart described later.

FIG. 4 is a functional block diagram showing a main configuration of the electronic paper display control unit 40.
4, the electronic paper display control unit 40 includes a display unit (electronic paper) 41, first to ninth drive circuits 42a to 42i, a communication unit 43, a storage unit 44, a power storage unit 45, and a control unit. 46, first to ninth decoding circuits 47a to 47i, and the like.

  The display unit 41 is composed of electronic paper, which is a display medium having a memory property in which an image after writing is retained even in a non-powered state, and is composed of, for example, cholesteric liquid crystal, a transparent film, a transparent electrode, a source line, and a gate line The The display part 41 displays an image based on each drive circuit 42a-42i. The cholesteric crystal is preferably composed of, for example, three colors of blue, green, and red from the viewpoint of colorization.

  The first to sixth drive circuits 42a to 42f are configured by, for example, source drivers, and the seventh to ninth drive circuits 42g to 42i are configured by, for example, gate drivers. A pair of different secret key information and public key information is assigned to each of these drive circuits. Therefore, for example, image information encrypted with the public key information assigned to the first drive circuit 42a is not decrypted with the secret key information assigned to the sixth drive circuit 42f. Note that the number of bits of the assigned key is desirably a low bit number such as 8 bits, 16 bits, 32 bits, etc. from the viewpoint of speeding up of encryption and decryption. Further, the number of driving circuits is not limited, and may be three or six, for example.

  The communication unit 43 includes an antenna. The communication unit 43 transmits and receives various information to and from the communication device 10 and the mobile phone 20. A technique related to contactless wireless communication such as RFID may be used.

The storage unit 44 is an example of the storage circuit of the present invention, and is configured by a RAM or a ROM. Image information transmitted from the communication unit 43 and identification information (for electronic paper) for identifying the electronic paper 41 are stored. When the electronic paper 41 is configured to be replaceable with respect to the electronic paper display control unit 40, the identification information read from the electronic paper 41 is stored in the storage unit 44.
The power storage unit 45 includes a battery or the like. The power storage unit 45 supplies power to the control unit 46 and the like.
The control unit 46 is composed of a CPU. The control unit 46 comprehensively controls each function in the electronic paper display control unit 40.

  The first decoding circuit to the ninth decoding circuit 47a to 47i are decoding circuits configured by hardware circuits, and for example, technology used in an SSL accelerator or the like is used. By implementing the decoding circuits 47a to 47i in hardware, the processing speed can be increased as compared with the case of decoding by software processing. Each decryption circuit 47a to 47i obtains and decrypts the secret key information possessed by each pair of drive circuits 47a to 47i from the image information encrypted with the public key information. The decoded image information is transmitted to each of the drive circuits 41a to 41i.

  Further, when the encryption is a stream cipher, the decryption circuits 47a to 47i may use a technique for decrypting the stream cipher (stream decryption technique), thereby reducing the circuit scale and processing. The speed can be increased. The stream cipher may be either an asynchronous type or a synchronous type, and for example, there is an NFSR (Nonliner Feedback Shift Register) cipher if it is an asynchronous type, and a Burnham cipher if it is a synchronous type.

In the above description, the electronic paper 41 is not limited to the above-described cholesteric liquid crystal display type electronic paper, but may be an electronic paper such as an organic EL film display, an electrophoretic display, an electronic powder fluid (registered trademark) display, or the like. Good. In this way, by using the electronic paper 41 that is lightweight and excellent in portability, for example, it is easy to use and can be seen immediately regardless of the feature of quick electronic reporting, time and place. It is preferable that both the characteristics of the paper document can be exhibited. In addition, although what hold | maintains display content with a non-power supply is used preferably, what is equipped with power supplies, such as a solar cell, and hold | maintains display content with the electric power of the said power supply may be used.
The electronic paper display control unit 40 can use a known display control device according to the driving method of the electronic paper to be used. For example, in the case of optical writing type electronic paper, an image to be displayed is converted into a one-dimensional or two-dimensional optical image, and recording is performed by irradiating the photoelectric conversion layer of the electronic paper to which a voltage is applied. Further, when a dot matrix image is formed by arranging matrix electrodes on electronic paper, the drive circuit of the matrix circuit and the matrix electrode of electronic paper are connected using a connector or the like, and display control of the image is performed.
Note that the electronic paper 41 and the electronic paper display control unit 40 may be integrated, or the display unit (electronic paper) 41 may be configured to be exchangeable. In the latter case, since the electronic paper display control unit 40 is shared, a system can be realized at low cost, and the display medium is also reduced in weight, so that convenience as electronic paper is enhanced. In the case of a commutative configuration, a reading mechanism is provided for reading the identification information stored in the electronic paper 41 to the electronic paper display control unit 40 as described above.

  Next, each operation | movement of the communication apparatus 10, the server apparatus 30, and the electronic paper 40 mentioned above is demonstrated.

First, the operation of the communication device 10 will be described with reference to FIG.
As shown in FIG. 5, the communication apparatus 10 first continues in a standby state until it receives identification information and a plurality of public key information stored in the storage unit 44 from the electronic paper display control unit 40 (step S1). Is received, the identification information and the plurality of public key information are aggregated and encrypted with the first common key information held by itself (step S2). Next, when the encryption of the identification information or the like is completed, the communication device 10 transmits this to the mobile phone 20 (step S3).

Next, the operation of the server device 30 will be described with reference to FIG.
As shown in FIG. 6, the server device 30 continues to be in a standby state until it receives encrypted identification information from the mobile phone 20 (step S11). This is decrypted with the common key information of 1 (step S12). The first common key information constitutes a pair with the first common key information included in the communication device 10 and may be stored in advance by an administrator who manages the server device 30 or the like.

  Next, the server device 30 divides the image information to be transmitted to the electronic paper display control unit 40 based on the image transmission request from the mobile phone 20 (step S13). More specifically, the image information is divided into frame units or packet units. This division processing is performed in accordance with the matrix format of the drive circuit in the electronic paper 41. For example, in the present embodiment, since the drive circuit is composed of six source drivers and three gate drivers, the image information is divided into nine in units of frames.

  The number of drive circuits can be determined based on the number of public key information received by the server device 30. In addition, in order to generate array information to be described later, an identification number or a division time may be attached to each piece of image information in the division order when dividing the image information.

  Next, the server device 30 encrypts each of the divided image information with the public key information (step S14). The public key information decrypted in the process of step S12 is used as the public key information. Thereby, a plurality of encrypted image information is generated.

  Next, the server device 30 randomly rearranges the plurality of encrypted image information (step S15). The rearrangement is performed based on a random number generated by a known pseudo-random number generation method such as a mixed congruential method, a squaring method, a Mersenne twister, or a chaos random number.

  Next, the server device 30 generates array information for rearranging the rearranged encrypted image information in a normal order (step S16). The array information is composed of, for example, identification numbers and time divisions of image information arranged in time series. In other words, by returning the divided image information in the order of the division times, the encrypted image information can be arranged in the normal order. In the case of identification numbers, for example, information arranged in ascending order may be used as the array information. Note that the server device 30 may not perform the processing when the rearrangement processing is not performed.

  Next, the server device 30 encrypts the array information with the second common key information (step S17). The second common key information may be stored in advance by an administrator who manages the server device 30 or the like.

  Next, the server device 30 adds the array information to the top of the plurality of pieces of image information (step S18). Thereby, the encrypted arrangement information is arranged at the head of the rearranged image information. The server device 30 may arrange the array information at the head of all the divided pieces of image information scheduled to be transmitted.

  Next, the server device 30 transmits image information and the like to the mobile phone 20 that has output the image transmission request toward the electronic paper display control unit 40 having the identification information (step S19).

Next, the operation of the electronic paper display control unit 40 will be described with reference to FIGS.
As shown in FIG. 7, the electronic paper display control unit 40 first continues in a standby state until it receives encrypted image information or the like from the mobile phone 20 (step S21). Store (step S22).

  Next, the electronic paper display control unit 40 extracts sequence information from the image information (step S23), and decrypts the sequence information with the second common key information held by itself (step S24). The second common key information constitutes a pair with the second common key information of the server device 30 and may be stored in advance by an administrator who manages the electronic paper 41 or the like.

  Next, the electronic paper display control unit 40 rearranges the image information based on the decrypted arrangement information (step S25), and decrypts each image information using the respective secret key information (step S26). These processes will be described with reference to FIG. 8. First, as shown in FIG. 8, the randomly arranged encrypted image information is rearranged in the normal order by the decrypted array information. Then, each image information is decoded by each decoding circuit arranged in the electronic paper display control unit 40. As a result, the decrypted image information is output to each of the drive circuits 41a to 41i.

  Next, the electronic paper display control unit 40 displays an image based on each piece of image information (step S27), and ends the process. Thus, the security of the image to be displayed is ensured by the identification information and public key information that the electronic paper 41 has.

(Second Embodiment)
Subsequently, a second embodiment of the present invention will be described.
In the present embodiment, in the electronic paper display control unit 40 described in the first embodiment, information obtained by connecting a plurality of public key information is stored as identification information, and third information is stored in the communication device 10 and the electronic paper 41, respectively. The common key information is shared, and the identification information encrypted with the third common key information is transmitted to the communication device 10. Note that the third common key information may be stored in advance by an administrator who manages the communication device 10 and the electronic paper 41.

  When receiving the encrypted identification information, the communication device 10 decrypts it with the third common key information held by itself. Thereby, information leakage of identification information between the communication device 10 and the electronic paper 41 is suppressed.

  Further, when the server device 30 encrypts the image information divided by each public key information, each image information is sequentially subjected to XOR (exclusive OR) processing, and the subsequent encrypted image information is used as the subsequent information. Encrypt so that the image information changes. Thereby, information leakage of image information between the server device 30 and the electronic paper 41 is suppressed.

  As described above, the user who uses the image display system according to the above-described embodiment carries the communication device 10, the mobile phone 20, the electronic paper display control unit 40, and the electronic paper 41 to the destination. When an image is displayed on the paper 41, since the image transmitted from the server device 30 is encrypted based on the transmission request from the mobile phone 20, the possibility of information leakage from the image during communication is reduced. When displaying, the decoded image is displayed. Further, since it is not necessary to cause the mobile phone 20 to perform complicated encryption, the reduction of the charging capacity is delayed.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific embodiments according to the present invention, and various modifications are possible within the scope of the gist of the present invention described in the claims.・ Change is possible.

  In the above-described embodiment, the mobile phone 20 transmits these pieces of information such as encrypted identification information to the server device 30 and encrypted image information to the electronic paper display control unit 40. May be forwarded based on its own function, and the reception of such information may be displayed on the display screen of the mobile phone 20 to prompt the user to send it. You may make it let.

  ADVANTAGE OF THE INVENTION According to this invention, the information leakage at the time of transmitting an image to an electronic paper display control part can be suppressed, suppressing the fall of the electrical storage capacity of a portable information terminal, and industrial applicability is high.

It is a block diagram of an image display system. It is a functional block diagram which shows the principal part structure of a communication apparatus. It is a functional block diagram which shows the principal part structure of a server apparatus. It is a functional block diagram which shows the principal part structure of electronic paper. It is a flowchart which shows an example of operation | movement of a communication apparatus. It is a flowchart which shows an example of operation | movement of a server apparatus. It is a flowchart which shows an example of operation | movement of electronic paper. It is a figure for demonstrating the decoding process in electronic paper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Communication apparatus 11 Communication part 12 Storage part 13 Encryption part 14 Control part 20 Cellular phone 30 Server apparatus 31 Communication part 32 Storage part 33 Image information division part 34 Encryption part 35 Sequence information generation part 36 Control part 40 Electronic paper display control Part 41 Display part (electronic paper)
42a-42i 1st drive circuit-9th drive circuit 43 Communication part 44 Storage part 45 Power storage part 46 Control part 47a-47i 1st decoding circuit-9th decoding circuit

Claims (6)

A plurality of drive circuits to display the image, different pair of secret key information and public key information is assigned to each the electronic paper having a memory property that holds a written image the image display area, a memory circuit electronic paper identification information for identifying the electronic paper has been stored, respectively constitute a pair, the secret key information image information encrypted by the public key information of said plurality of drive circuits comprising a plurality of decoding circuits, a, through the communication device transmits the electronic paper identification information and the public key information to the server apparatus, the image information that has been encrypted by the public key information server for decoding by received from the apparatus, the image information encrypted decoded by the plurality of decoding circuits, and displays the image information decoded with respect to the electronic paper And the child paper display control unit,
First common key encrypted by the information to aggregate the electronic paper identification information and the public key information received from the electronic paper display control unit, and the communication device to be transmitted to the server device,
A plurality of image information divided from one image information, the first common key information respectively encrypted with the public key information decoded by the divided source is the one reproduced information reproducible image information is in conjunction with, and the server device to be transmitted to the electronic paper display control unit having the electronic paper identification information,
An image display system comprising: The reproduction information includes sequence information that is rearranged in a regular order,
2. The server device according to claim 1, wherein when the plurality of divided pieces of image information are respectively encrypted and transmitted to the electronic paper display control unit, the server device rearranges them in a random order and transmits them. Image display system. The server device adds the reproduction information to the head of at least one of the plurality of divided image information when each of the plurality of divided image information is encrypted and transmitted to the electronic paper display control unit. the image display system according to claim 1 or 2, characterized in that transmitting Te. Each of the server device and the electronic paper display control unit stores second common key information,
The server device encrypts the reproduction information with its second common key information,
The image display system according to any one of claims 1 to 3, wherein the electronic paper decrypts the reproduction information using its second common key information.   The image display system according to claim 1, wherein the identification information is information obtained by connecting the plurality of public key information.   The image display system according to claim 1, wherein the decryption circuit is a circuit for decrypting encryption by stream cipher.

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