JP3850942B2 - Encrypted digital information decryption method and digital information browsing method - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an encrypted digital information decryption method for preventing digital information received by a user from being copied or altered when using the digital information, and a digital information browsing method using the encrypted digital information decryption method About.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, systems in which software such as computer programs and video works are converted into digital information and used by a specific user or an unspecified number of users using various communication networks have been used. When constructing this type of system, it is necessary to effectively prevent the user's received data from being duplicated or tampered with. If this preventive measure is not taken, for example, if various exhibitions are held on a communication network, the video works exhibited there will be copied without permission, and this will be applied after the exhibition period is over. It is possible to let the exhibitor voluntarily exhibit, and the interests of the legitimate organizer of the exhibition will be harmed. In addition, company information, electronic newspapers, novels, and the like are widely browsed as digital information through a communication network. In this case, the same problem occurs.
[0003]
As a prior art for solving such a problem, Japanese Patent Laid-Open No. 7-131449 discloses that digital information sent from an information center to an information processing apparatus is arbitrarily copied or altered on the information processing apparatus side. When the validity of the information processing device is confirmed, digital information obtained by adding a tamper-proof authenticator to the digital information requested by the information processing device is converted into an encryption method using a common key. When the encrypted digital information is sent to the information processing apparatus by communication and the encrypted digital information is used in the information processing apparatus, falsification is verified by the fixed authenticator, and the encrypted digital information received only when the information is matched is preliminarily stored in the information processing apparatus. There is disclosed a digital information communication system in which decoding is performed using a provided decoding unit.
[0004]
[Problems to be solved by the invention]
However, according to this prior art, it is necessary to provide a configuration that is used only for browsing information, such as a common key storage unit, an authentication data creation unit, an information storage unit, and a decryption unit, on the information processing device side. It is disadvantageous in cost. In addition, since an identifier required for data use is fixed, there is a problem that a third party can easily enter the system. Further, in the above-described prior art, since a common key is required for decryption of encrypted digital information, it is necessary to manage the common key on the information providing side, which causes a problem that the configuration on the information providing side becomes complicated.
[0005]
In addition, according to the above-described prior art, once digital information is taken into the information processing apparatus, the digital information taken in using the decoding system provided in advance on the information processing apparatus can be decoded and used at any time. Therefore, it is possible to store digital information in the information processing apparatus and allow a third party to view it arbitrarily. Therefore, although it is possible to prevent the digital information from being copied or falsified, it is not possible to prevent a third party from arbitrarily viewing the captured digital information.
[0006]
An object of the present invention is to allow a digital information supplied from an information center to be used by a user in each information processing apparatus, so that the encrypted digital information supplied from the information center can be decrypted only by the information processing apparatus that directly receives it. It is an object to provide a method for decrypting encrypted digital information.
[0007]
Another object of the present invention is to allow a user to use digital information supplied from an information center in each information processing apparatus, and only in an information processing apparatus that directly receives encrypted digital information supplied from the information center. The object is to provide a digital information browsing method that enables browsing.
[0008]
[Means for Solving the Problems]
The feature of the invention of claim 1 for solving the above problem is as follows: Consists of a central processing unit, a database unit, and a communication control unit Information center ~ side In a method for decrypting encrypted digital information sent from an information processing apparatus to an information processing apparatus, an information center ~ side From information processing equipment Accumulated in the database section Digital information By the communication control unit When sending, a first identifier for the information processing device, a second identifier for the information center, and information when the information processing device accesses the information center The information can be used to determine whether or not a predetermined time has passed since the time when the digital information was taken into the information processing apparatus. And the third identifier By central processing unit And obtaining encrypted information including the obtained primary first to third identifiers and the digital information. By the central processing unit make,
A decryption program for decrypting the encrypted information and the encrypted information By the communication control unit When the digital information is decrypted from the encrypted information using the decryption program, the information center The central processing unit Requests the first to third identifiers in response to this request By the central processing unit The newly acquired secondary first to third identifiers are stored in the information center. Via the communication control unit from the side Only when the secondary first to third identifiers are matched with the primary first to third identifiers included in the encrypted information and matched by the decryption program from the digital information. The information can be decrypted.
[0009]
According to the first aspect of the present invention, when the required digital information is sent from the information center to the information processing apparatus, the first to third identifiers are transmitted as encrypted information together with the digital information as primary identifiers. When decrypting digital information encrypted in the information processing apparatus using the decryption program sent to the information processing apparatus together, the information center requests the information center again from the information center, and the information center Only when the first to third identifiers are newly acquired and transmitted to the information processing apparatus as secondary first to third identifiers, and the primary and secondary identifiers are collated and matched. The encrypted digital information in the encrypted information can be decrypted, so that the decrypted program and the encrypted information can be decrypted by an information processing device different from the information processing device once received. When you try to decode the Le information, first through the primary of the first to third identifiers and secondary do not coincide with the third identifier, it is possible to prohibit the decryption process. In this way, it is possible to prevent the digital information from being used in a terminal other than the information processing apparatus that has received the decryption program and the encrypted information from the information center.
[0010]
The first identifier is information of the information processing apparatus, and can be determined using an address of the information processing apparatus determined on the network, a manufacturing number of a component (CPU or the like) used in the information processing apparatus, and the like. .
[0011]
The second identifier is information of the information center. The address of the information center determined on the network, the manufacturing number of a component (CPU, etc.) used in the information center, and the information center manager registered in the information center. Can be determined by quoting the keyword etc.
[0012]
In addition, since the third identifier is information at the time of access to the information center, it is possible to prohibit the decryption there even in the information processing apparatus that has received the decryption program and the encrypted information from the information center. It is. That is, the third identifier is set as time information managed by the information center, and when a predetermined time or more elapses from the time when the decryption program and the encrypted information are taken into the information processing apparatus, the primary third identifier and the secondary By determining that the third identifier does not match, even a legitimate information processing apparatus cannot perform decoding, and the use of digital information can be restricted. The third identifier is information at the time of access to the information center, the time managed by the information center, the cumulative number of accesses from outside the information center, the last access time from outside the information center, the external storage of the information center It can be determined by using the capacity of the device. According to this configuration, for example, when an exhibition is held on a communication network, it is possible to prevent the information processing apparatus from using digital information received from the information center after the exhibition date. If the tolerance that is determined to match the primary third identifier and the secondary third identifier is reduced, the digital information can be used only once in the information processing apparatus. Even if the tolerance for determining that the primary third identifier and the secondary third identifier match is increased, the information processing apparatus that receives the decryption program and the encrypted information from the information center has different information. When this is sent to the processing device, a mismatch between the first and second identifiers occurs, so that this digital information can be prevented from being used in another information processing device.
[0013]
The feature of the invention of claim 2 is that Consists of a central processing unit, a database unit, and a communication control unit Information center The database part of Digital information stored in The communication control unit In a digital information browsing method for browsing in an information processing apparatus connected to the information center via a communication line, The central processing unit Against Accumulated in the database section If there is a request to view digital information, Said Information center ~ side A first identifier for the information processing device, a second identifier for the information center, and information at the time of access of the information processing device to the information center. The information can be used to determine whether or not a predetermined time has passed since the time when the digital information was taken into the information processing apparatus. And the third identifier By central processing unit And obtaining encrypted information including the obtained primary first to third identifiers and the digital information. By the central processing unit A decryption program for creating and decrypting the encrypted information and the encrypted information By the communication control unit When the digital information is decrypted from the encrypted information using the decryption program, the information center The central processing unit Requests the first to third identifiers in response to this request By the central processing unit The newly acquired secondary first to third identifiers are stored in the information center. ~ side From Via the communication controller The secondary first to third identifiers are collated with the primary first to third identifiers included in the encrypted information, and the decryption program is used only when the collation results match. The digital information is decrypted from the encrypted information, and the required digital information obtained thereby is converted into a predetermined form by the output control unit, output to the output device, and browsed.
Information at the time of access to the information center of the information processing apparatus The time including the time managed in the information center, the cumulative number of external accesses to the information center, the last access time from the outside to the information center, and the used capacity of the external storage device of the information center It is information determined using information that can identify Third identifier
[0014]
According to the invention of claim 2, when there is a browsing request from the information processing apparatus, when the required digital information is sent from the information center to the information processing apparatus, the first to third identifiers are encrypted together with the digital information as primary identifiers. Information is transmitted as the conversion information, and the decoding program is also transmitted at that time. When the information processing apparatus tries to decrypt the encrypted information using the decryption program, the information processing apparatus requests the information center again from the information center, and newly creates the first to third identifiers in the information center. This is transmitted to the information processing apparatus as secondary first to third identifiers. When trying to decrypt the encrypted information in an information processing apparatus different from the information processing apparatus that once received the decryption program and the encrypted information, the primary first to third identifiers coincide with the secondary first to third identifiers. Without the decryption process, browsing in the information processing apparatus can be prohibited. In this way, it is possible to prevent digital information from being browsed at terminals other than the information processing apparatus that has received the decryption program and the encrypted information from the information center.
[0015]
The first identifier is information of the information processing apparatus, and can be determined using an address of the information processing apparatus determined on the network, a manufacturing number of a component (CPU or the like) used in the information processing apparatus, and the like. . The second identifier is information of the information center. The address of the information center determined on the network, the manufacturing number of a component (CPU, etc.) used in the information center, and the information center manager registered in the information center. Can be determined by quoting the keyword etc.
[0016]
In addition, since the third identifier is information at the time of access to the information center, it is possible to prohibit the decryption there even in the information processing apparatus that has received the decryption program and the encrypted information from the information center. It is. That is, the third identifier is set as time information managed by the information center, and when a predetermined time or more elapses from the time when the decryption program and the encrypted information are taken into the information processing apparatus, the primary third identifier and the secondary By determining that the third identifier does not match, even a legitimate information processing apparatus cannot perform decoding, and the use of digital information can be restricted. The third identifier is information at the time of access to the information center, the time managed by the information center, the cumulative number of accesses from outside the information center, the last access time from outside the information center, the external storage of the information center It can be determined by using the capacity of the device.
[0017]
Therefore, for example, when an exhibition is held on a communication network, it is possible to prevent the information processing apparatus from browsing the digital information received from the information center after the exhibition date. If the tolerance that is determined to match the primary third identifier and the secondary third identifier is reduced, the digital information can be browsed only once in the information processing apparatus. Even if the tolerance for determining that the primary third identifier and the secondary third identifier match is increased, the information processing apparatus that receives the decryption program and the encrypted information from the information center has different information. When this is sent to the processing device, a mismatch between the first and second identifiers occurs, so that this digital information can be prevented from being used in another information processing device.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing an example of an embodiment of a digital information browsing system according to the present invention. In FIG. 1, reference numeral 1 denotes an information center, in which various digital information is stored in the database unit 11, and the required information is obtained in response to a search request from the information processing apparatus 3 connected to the information center 1 via the communication path 2. Digital information is transmitted to the information processing apparatus 3. Although only one information processing device 3 is shown in FIG. 1, in reality, a large number of information processing devices 3 can be connected to the information center 1 via the communication path 2.
[0019]
The database unit 11 of the information center 1 is connected to a central processing unit 12 that is a part of a computer device. The central processing unit 12 includes a primary second identifier B and a secondary secondary identifier E based on the address of the information center 1, and a primary third identifier C based on time data managed by the information center 1. An identifier output unit 13 that outputs a secondary third identifier F and an encryption unit 14 that encrypts the identifier are provided. A search unit 15 searches for required digital information from the database unit 11 in response to a search request from the information processing apparatus 3, and the searched digital information is encrypted by the encryption unit 16. Each encrypted output from the encryption units 14 and 16 is sent to the information processing device 3 via the communication control unit 17.
[0020]
The information processing apparatus 3 is configured as a computer system including a central processing unit 31 and can perform data communication with the information center 1 via the communication control unit 32. The identifier output unit 33 configured in the central processing unit 31 is configured by an identifier output program sent from the information center 1, and the identifier output unit 33 performs primary processing based on the address of the information processing device 3. A first identifier A is created. The decryption unit 34 configured in the central processing unit 31 is configured by a decryption program sent from the central processing unit 12 of the information center 1 together with the encrypted information. And the secondary first identifier D is created based on the address of the information processing device 3. An output control unit 35 converts the digital information decoded by the decoding unit 34 into a required format and sends it to the output device 36.
[0021]
Next, the flow of processing for browsing digital information will be described with reference to FIGS.
[0022]
When an access request for digital information is transmitted in the information processing apparatus 3 in step 41, the access right received in the information center 1 is authenticated in step 42. This access right authentication can be performed by a known method using a password or other means. In the next step 43, an accessible digital information list stored in the database unit 11 is generated, and the generated digital information list is transmitted to the information processing apparatus 3. In step 44, digital information is selected based on the digital information list received by the information processing apparatus 3, and the selected digital information is transmitted to the information center 1 as selected digital information.
[0023]
In step 45, a search for digital information is performed based on the received selected digital information. This search for digital information is performed by searching the database unit 11 by the search unit 15. After retrieving the digital information, an identifier output program is transmitted from the information center 1 to the information processing apparatus 3 side in order to obtain the primary first identifier A. In step 46, the identifier A of the information processing apparatus 3 is acquired based on the identifier output program for acquiring the primary first identifier A. The acquired identifier A is transmitted to the information center 1. As already described, the identifier A is created based on the address of the information processing apparatus 3, and it is also possible to use the manufacturing number of a part used in the information processing apparatus 3.
[0024]
In this way, when the primary first identifier A is received by the information center 1, step 47 is entered, where the primary second and third identifiers B and C are output from the identifier output unit 13. The primary second and third identifiers B and C are not limited to the information form shown in the example of the present embodiment, and the second identifier is information of the information center 1 and is determined on the network. The information center 1 address, the manufacturing number of a component (such as a CPU) used in the information center 1, a keyword registered in the information center 1 by the information center manager, and the like can be cited. The third identifier is information at the time of access to the information center 1, the time managed by the information center 1, the cumulative number of accesses from outside the information center 1, the last access time from outside the information center 1, information It can be determined using the capacity used of the external storage device of the center 1.
[0025]
The primary first to third identifiers A, B, and C thus obtained are encrypted in the encryption unit 14 in step 48. Next, in step 49, the digital information selected in step 44 and retrieved in step 45 is encrypted in the encryption unit 16 to obtain encrypted digital information.
[0026]
In this way, if the primary encryption identifiers A, B, and C and the encrypted digital information are prepared as the encrypted information in the information center 1, a decryption program necessary for decrypting them is stored in the database. The decryption program is read from the unit 11 and transmitted to the information processing apparatus 3 together with the encryption information. The decryption program sent to the information processing apparatus 3 performs a function for decrypting various data in the decryption unit 34 of the central processing unit 31 of the information processing apparatus 3. The steps performing these functions are shown in the frame indicated by the symbol EC.
[0027]
In step 50, first, the first to third identifiers A, B, and C are first decoded based on a decoding program. The decryption program also has a function for acquiring the secondary first identifier D. In step 51, the secondary first identifier D is acquired based on the unique information of the information processing apparatus 3. . The secondary first identifier D is created based on the address of the information processing device 3, as with the primary first identifier A. Therefore, when decryption is performed by the same information processing apparatus 3 as the information processing apparatus 3 accessed for digital information search, the primary first identifier A and the secondary first identifier D match. Become. Otherwise, the primary first identifier A and the secondary first identifier D will not match.
[0028]
The secondary first identifier D acquired in step 51 is transmitted to the information center 1. In the information center 1 that has received the secondary first identifier D, the secondary second and third identifiers E and F are output from the identifier output unit 13 in step 52. Here, since the secondary second identifier E is based on the address of the information center 1, as long as the information processing apparatus 3 is connected to the information center 1, the primary second identifier B and the secondary It matches the second identifier E. Otherwise, the primary second identifier B and the secondary second identifier E do not match. Since the secondary third identifier F is time data managed by the information center 1, the primary third identifier C and the secondary third identifier F do not completely match in any case. However, when the series of processes described above are performed normally, the difference is slight. In step 53, the secondary first to third identifiers D, E, and F output in step 52 are encrypted by the encryption unit 14, and the encrypted encryption identifiers D, E, and F are information processing apparatuses. 3 is transmitted.
[0029]
In step 54, the encrypted identifiers D, E, and F are decrypted. In step 55, the primary first to third identifiers A, B, and C are compared with the secondary first to third identifiers D, E, and F. Is done. As already described, if the above-described processing is normally performed between the information center 1 and the information processing apparatus 3, the primary first and second identifiers A and B are secondary first and second identifiers. 2 completely matches the identifiers D and E. The primary third identifier C and the secondary third identifier F do not completely match because of the time data. However, in step 55, the difference is recognized to some extent and a match / mismatch is determined. Therefore, in the present embodiment, the time elapsed from the execution of step 47 to the execution of step 52 allows a difference to a value TA that is slightly larger than the time value T required in normal processing. In step 55, only when the primary first to third identifiers A, B, and C match the secondary primary to third identifiers D, E, and F in the above meaning, step 56 is entered. Decryption of the encrypted digital information is executed by a decryption program. If there is no match between the primary first to third identifiers A, B, and C and the secondary primary to third identifiers D, E, and F in step 55, the encryption in step 56 is performed. The digital information in the digitized information is not decoded.
[0030]
When the decryption of the encrypted digital information in the encrypted information is executed by the decryption program in step 56, the decrypted digital information is output in step 57, and the digital information is displayed in the required form on the output device 36. . The output device 36 can be a CRT display device, a speaker, or the like.
[0031]
According to this browsing system, when there is a browsing request from the information processing apparatus 3, when the required digital information is sent from the information center 1 to the information processing apparatus 3, primary first to third identifiers A, B, and C The digital information is encrypted and transmitted as encrypted information. At that time, the decryption program is also transmitted. When the information processing apparatus 3 attempts to decrypt the digital information encrypted using the decryption program, the information center 3 requests the information center 1 for a set of first to third identifiers, and the information center 1 1st to 3rd identifiers are newly created and transmitted to the information processing apparatus 3 as secondary 1st to 3rd identifiers D, E, and F. Therefore, when the encrypted digital information is decrypted in an information processing apparatus different from the information processing apparatus 3 that once received the encrypted digital information and the decryption program, the primary first to third identifiers A, B, and C and the secondary The first to third identifiers D, E, and F do not coincide with each other, the decoding process is prohibited, and browsing in the information processing apparatus can be prohibited. In this way, it is possible to prevent digital information from being browsed at terminals other than the information processing apparatus that has received the encrypted information and the decryption program from the information center.
[0032]
The first identifiers A and D are information on the information processing apparatus, and are determined by using the address of the information processing apparatus determined on the network, the manufacturing number of a component (CPU etc.) used in the information processing apparatus, and the like. be able to. The second identifiers B and E are information of the information center. The information center address determined on the network, the manufacturing number of a part (CPU etc.) used in the information center, and the information center manager The keyword registered in the center can be cited and determined.
[0033]
Further, since the third identifiers C and F are information at the time of access to the information center 1, even if the information processing apparatus 3 receives the encrypted information and the decryption program from the information center 1, the third identifiers C and F are decrypted there. Can be prohibited. In the present embodiment, when the third identifiers C and F are time information managed by the information center 1, and when a predetermined time TA or more has elapsed since the time when the encrypted information and the decryption program were taken into the information processing apparatus 3. Since the primary third identifier C and the secondary third identifier F are determined to be inconsistent, even in a valid information processing apparatus, a predetermined time TA from reception of encrypted information to decryption is obtained. When the time has elapsed, decoding is impossible and the use of digital information is restricted. The third identifiers C and F are information at the time of access to the information center 1, the time managed by the information center 1, the cumulative number of accesses from outside the information center 1, and the last access from outside the information center 1. It can be determined using the time, the used capacity of the external storage device of the information center 1, and the like.
[0034]
Therefore, when an exhibition is held on a communication network using this system, the digital information received by the information processing apparatus 3 from the information center 1 can be obtained by setting the predetermined time TA to an appropriate length. It is also possible to prevent browsing thereafter. If the allowable time difference TA determined to match the primary third identifier C and the secondary third identifier F is appropriately selected (for example, about several seconds), the digital information is allowed to be browsed once in the information processing device 3. It can also be done.
[0035]
【The invention's effect】
According to the first aspect of the present invention, when the required digital information is sent from the information center to the information processing apparatus, the first to third identifiers are transmitted as encrypted information together with the digital information as primary identifiers. When the encrypted information is decrypted in the information processing apparatus using the decryption program sent together to the information processing apparatus, the information processing apparatus requests the information center again from the information center, and the information center first Or a third identifier is newly acquired and transmitted to the information processing apparatus as secondary first to third identifiers, and encrypted digital data only when the primary and secondary identifiers are matched and matched. Since the information can be decrypted, if the encrypted digital information is decrypted in an information processing apparatus different from the information processing apparatus that once received the decryption program and the encrypted information, the primary First through third identifier and the do not match the secondary of the first to third identifier, it is possible to prohibit the decryption process. In this way, it is possible to prevent unauthorized use of digital information in terminals other than the information processing apparatus that has received the decryption program and the encrypted information from the information center. In addition, since the third identifier is information at the time of access to the information center, it is possible to prohibit the decryption there even in the information processing apparatus that has received the decryption program and the encrypted information from the information center. The primary third identifier and the secondary third identifier are determined to be inconsistent when a predetermined time or more has elapsed since the time when the decryption program and the encrypted information were taken into the information processing apparatus. Accordingly, even a legitimate information processing apparatus cannot perform decryption, and the use of digital information can be restricted. Therefore, for example, when an exhibition is held on a communication network, it is possible to prevent the information processing apparatus from using digital information received from the information center after the exhibition date. If the tolerance that is determined to match the primary third identifier and the secondary third identifier is reduced, the digital information can be used only once in the information processing apparatus.
[0036]
According to the second aspect of the present invention, it is possible to prevent the digital information from being browsed at a terminal other than the information processing apparatus that has received the encrypted information and the decryption program from the information center. Since the third identifier is information at the time of access to the information center, it is possible to prohibit browsing of the information processing apparatus that has received the decryption program and the encrypted information from the information center. . Therefore, for example, when an exhibition is held on a communication network, it is possible to prevent the information processing apparatus from browsing the digital information received from the information center after the exhibition date, It is also possible to allow browsing of information only once.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an example of an embodiment of a digital information browsing system according to the present invention.
FIG. 2 is a flowchart for explaining a flow of processing for browsing digital information in the digital information browsing system of FIG. 1;
[Explanation of symbols]
1 Information Center
2 communication channel
3 Information processing equipment
11 Database section
12, 31 Central processing unit
13, 33 Identifier output unit
14, 16 Encryption unit
15 Search section
17, 32 Communication control unit
34 Decryption unit
35 Output controller
36 Output device
A Primary primary identifier
B Primary second identifier
C primary third identifier
D secondary first identifier
E Secondary secondary identifier
F Secondary third identifier

Claims (2)

In a method for decrypting encrypted digital information sent to an information processing device from an information center side comprising a central processing unit, a database unit, and a communication control unit ,
When sending the digital information stored in the database unit from the information center side to the information processing device by the communication control unit ,
A first identifier for the information processing device, a second identifier for the information center,
Information at the time of access to the information center of the information processing apparatus, and information that can determine whether or not a predetermined time has passed since the time when the digital information was taken into the information processing apparatus . An identifier is acquired by the central processing unit ,
The central processing unit creates encrypted information including the obtained primary first to third identifiers and the digital information,
The decryption program for decrypting the encrypted information and the encrypted information are sent to the information processing apparatus by the communication control unit ,
In the information processing apparatus,
When decrypting the digital information from the encrypted information using the decryption program, request the first to third identifiers to the central processing unit of the information center,
In response to this request, the secondary first to third identifiers newly acquired by the central processing unit are received from the information center side via the communication control unit ,
The digital information is obtained from the encrypted information by the decryption program only when the secondary first to third identifiers match with the primary first to third identifiers included in the encrypted information. An encrypted digital information decryption method characterized by enabling decryption. In order to allow digital information stored in the database unit of an information center comprising a central processing unit, a database unit, and a communication control unit to be viewed on an information processing apparatus connected to the communication control unit via a communication line In the digital information browsing method of
When there is a request for browsing digital information stored in the database unit from the information processing device to the central processing unit of the information center,
On the information center side ,
A first identifier for the information processing apparatus, a second identifier for the information center, and information at the time of access to the information center by the information processing apparatus, and the time when the digital information is captured by the information processing apparatus A third identifier, which is information that can be used to determine whether or not a predetermined time or more has elapsed since, is acquired by the central processing unit ,
The central processing unit creates encrypted information including the obtained primary first to third identifiers and the digital information,
The decryption program for decrypting the encrypted information and the encrypted information are sent to the information processing apparatus by the communication control unit ,
In the information processing apparatus,
When decrypting the digital information from the encrypted information using the decryption program, request the first to third identifiers to the central processing unit of the information center,
In response to this request, the secondary first to third identifiers newly acquired by the central processing unit are received from the information center side via the communication control unit ,
Collating the secondary first to third identifiers with the primary first to third identifiers included in the encrypted information;
The digital information is decrypted from the encrypted information using the decryption program only when the collation results match, and the required digital information obtained thereby is converted into a predetermined form by the output control unit and output to the output device A digital information browsing method characterized by being browsed.

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