JP2004013564A - Viewing frequency restricted contents generating device, viewing frequency restricted contents reproducing device and its program, viewing frequency restricted contents distributing method and its program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a viewing frequency restricted contents generating device for making it easy for a purchaser to authenticate a contents provider, and for increasing the secrecy of contents, and for restricting the viewing frequency of contents, and reducing the load of devices at the contents provider side and the purchaser side at the time of distributing contents. <P>SOLUTION: This device is provided with an encrypted contents server 1 for encrypting contents by using common keys different for respective contents for storage, an encryption key server 2 for encrypting the common key by a provider side secret key at the contents provider side and a purchaser public key provided from the contents purchaser for storage, a ticket issuing server 3 for encrypting the viewing frequency of the purchaser, and for combining it with the encryption key for storage, and a multiplexing device for multiplexing the encrypted contents and the ticket. Then, the multiplexed encrypted contents are distributed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a viewing number limited content generation device, a viewing number limited content reproducing device, a viewing number limited content distribution method, a viewing number restricted content distribution program, and a viewing number restricted content reproduction program which handle encrypted content by limiting the number of viewing times. About.
[0002]
[Prior art]
Conventionally, when sending and receiving data on networks such as the Internet, only authorized recipients can decrypt the data and know the contents, and even if the data being communicated is seen by a third party, the contents of the data PKI (Public Key Infrastructure: public key infrastructure) is a framework for preventing data leakage and identifying a data sender. As a data communication technique using the PKI, a method such as SSL (Secure Sockets Layer) or an S / MIME (Secure Multipurpose Internet Mail Extensions) is well known and used in the Internet and the like. In these methods, data is encrypted and communicated, and only authorized recipients can decrypt the correct data, anyone can identify the sender of the data, and authenticate the sender and receiver of the data. And secure highly secure data communication.
[0003]
By the way, in the past, encryption was performed when transmitting multimedia contents such as moving images and sounds via a network, and decryption was performed when receiving. The above-described method such as SSL takes a long time to encrypt and decrypt, so that there is a problem that both the apparatus of the content provider and the apparatus of the purchaser place a burden on transmission and reception.
Furthermore, when content distribution is performed by these methods in both SSL and S / MIME, the number of viewing times of the content purchaser cannot be controlled, and once purchased content can be viewed without limitation. There was a problem that it would.
[0004]
[Problems to be solved by the invention]
As described above, there is a problem that it takes a long time to encrypt the content when distributing the conventional multimedia content, which places a burden on the device of the content provider. In addition, there is a problem in that once purchased content can be viewed without restriction.
[0005]
The present invention solves this problem and makes it easy for the purchaser to authenticate the content provider, has high confidentiality of the content, and can control the number of times the purchased content has been viewed. It is an object of the present invention to realize a viewing number limited content generation device, a viewing number limited content reproducing device, a viewing number limited content distribution method, a viewing number limited content distribution program, and a viewing number limited content reproduction program, in which the load on the user device is relatively small.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a video and / or audio
In a viewing count limited content generating apparatus for generating a viewing limited content in which the number of viewing of the content is limited to a number desired by the content purchaser, the content is encrypted at a stage of creating the content by using a different common key for each content. Content encrypting means for encrypting the content into encrypted content, and using the common key used for encryption by the content encrypting means with a providing side private key of a content providing side and a purchaser public key provided by the content purchaser. Key encryption means for encrypting and using the encrypted common key, and information indicating the desired number of times of viewing of the content purchaser, receiving this information by encrypting the information with the purchaser's public key to obtain encrypted number of times of viewing A number-of-times encrypting means, the encrypted common key encrypted by the key encrypting means, and Combining the encrypted viewing frequency information with a ticket generating unit that generates a ticket for permitting viewing, the encrypted content encrypted by the content encrypting unit, and the ticket generated by the ticket generating unit. Multiplexing means for multiplexing the ticket and distributing the content for distribution via the network, and distributing means for distributing the distribution content created by the multiplexing means via the network. Features.
[0007]
According to the viewing count-restricted content generation device, the content is encrypted with the common key in the content creation stage, and the common key used for the encryption and the ticket as the content permission message are encrypted with the public key. By doing so, a high degree of confidentiality can be maintained by a relatively easy processing method, and content to be distributed safely can be generated.
[0008]
Further, the viewing number limited content generation device is configured to store dedicated reproduction software for reproducing the distribution content and further provide a reproduction software storage unit for providing the content purchaser.
This allows the content purchaser to download the dedicated reproduction software at the time of contract and distribute and prepare the software in advance for actual use.
[0009]
The present invention is also directed to a viewing count-restricted content reproducing apparatus for reproducing the distribution content generated by the above-mentioned viewing count-restricted content generating apparatus, wherein a separating unit for separating the distribution content into the encrypted content and the ticket is provided. Dividing means for dividing the ticket separated by the separating means into the encrypted common key and the encrypted viewing number information, and the encrypted viewing number information divided by the dividing means A number-of-viewings information decryption means for decrypting with the purchaser private key, a provider public key previously provided by the content provider for the encrypted common key divided by the divider, and a purchaser private key of the content purchaser And a common key decrypting means for decrypting the encrypted data using the common key decrypted by the common key decrypting means. Decrypting the encrypted content, confirming that the content is legitimate from the content provider side, and playing back the decrypted content by using the viewing frequency information decoded by the viewing frequency information decoding device. Reproduction control means for controlling the number of times the content is reproduced by the means.
[0010]
According to the viewing number-restricted content reproducing apparatus, the ticket encrypted with the public key encryption is decrypted to obtain the common key and the desired number of times of viewing, and the content encrypted with the decrypted common key is decrypted and reproduced. Further, the number of times of reproduction can be controlled using the decrypted desired number of times of viewing.
[0011]
The present invention also provides a method for distributing content, such as a moving image and / or audio, which restricts the number of times of viewing to the number of times desired by the content purchaser, wherein the content is provided by using a different common key for each content. A content encryption process of encrypting the content at the stage of creating the content, obtaining desired information on the number of views of the content desired by the purchaser, and a purchaser information obtaining process of obtaining the purchaser's public key. A key encryption process of encrypting the common key used for encryption in the content encryption process with a provider private key of the content provider and the purchaser public key to obtain an encrypted common key; A viewing number encrypting step in which information is encrypted with the purchaser's public key to obtain encrypted viewing number information; A ticket creation step of creating a ticket for permitting viewing by combining the encrypted common key and the encrypted viewing number information encrypted in the viewing number encryption step, and encryption in the content encryption step; A multiplexing process of multiplexing the encrypted content and the ticket created in the ticket creation process to obtain content for distribution, and transmitting the delivery content obtained by multiplexing in the multiplexing process via a network. And a delivery process of delivering.
[0012]
This allows the content to be encrypted with the common key encryption at the stage of content creation, and the common key used for the encryption and the ticket as the content permission message can be encrypted with the public key encryption. A high-level confidentiality can be maintained by a relatively easy processing method, and a content distribution method capable of performing secure distribution can be realized.
[0013]
In addition, the present invention provides a content delivery system with a limited number of viewings used in a processing device of a delivery side that delivers a content such as a moving image and / or a sound via a network by limiting the number of viewings to a number desired by the content purchaser. In the program, the content is encrypted by using a different common key for each content to create the content at a stage of creating the content, and the common key used for encryption in the content encryption procedure is encrypted. And a key encryption procedure for encrypting the content with the provider's private key and the purchaser's public key to provide an encrypted common key, and encrypting the content purchaser's desired viewing frequency information with the purchaser's public key. The number of viewing times encryption procedure as encrypted viewing number information, the encrypted common key encrypted by the key encryption procedure, A ticket creation step of creating a ticket as a viewing permission message by combining the encrypted viewing count information encrypted by the number encryption procedure, the encrypted content encrypted by the content encryption procedure, and the ticket creation A multiplexing procedure for multiplexing the ticket created in the procedure and distributing the content for distribution via a network; and distributing the distribution content obtained by multiplexing in the multiplexing procedure via the network. And causing the processing device to execute the distribution procedure.
[0014]
With this program, the content can be encrypted with the common key encryption at the stage of creating the content, and the common key used for the encryption and the ticket as the viewing permission message of the content can be encrypted with the public key encryption. In addition, it is possible to maintain a high degree of confidentiality by a relatively easy processing method and generate contents that can be safely distributed. Further, since these encryptions can be prepared and performed in advance, this program can reduce the load on the transmitting / receiving device and the load on the network at the time of distribution.
[0015]
In addition, the present invention provides a content such as a moving image and / or a sound, wherein the number of times of viewing is limited to the number of times desired by the content purchaser. In the playback program, the number of views is limited to the number of times desired by the content purchaser.A separation procedure for separating the distribution content encrypted and distributed into an encrypted content and a ticket, and encrypting the ticket separated by the separation procedure. A dividing step of dividing the encrypted viewing number information into the encrypted common key and the encrypted viewing number information, a viewing number information decrypting step of decoding the encrypted viewing number information divided by the dividing step with a purchaser private key of the content purchaser, Providing a public key provided by the content providing side in advance from the content providing side and the content; A common key decryption procedure for decrypting with the purchaser's private key of the entrant, and a decryption of the encrypted content separated by the separation procedure using the common key decrypted by the common key decryption procedure, thereby obtaining a proper A playback procedure for playing back the content, and a playback control procedure for controlling the number of playbacks for playing back the content by this playback procedure based on the viewing number information decoded in the viewing number information decoding step. It is characterized by causing a processing device to execute the processing.
[0016]
With this program, a ticket encrypted with public key encryption can be decrypted to obtain a common key and a desired number of times of viewing, and the content encrypted with the common key can be decrypted and reproduced with the decrypted common key. The number of times of reproduction can be controlled using the decrypted desired number of times of viewing.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a viewing number limited content generation device, a viewing number limited content playback device, a viewing number limited content distribution method, a viewing number limited content distribution program, and a viewing number limited content playback program according to the present invention will be described in detail with reference to the drawings. .
[0018]
FIG. 1 is a block diagram showing the structure of a content-number-limited content generation device on the content provider side and its peripheral configuration, and FIG. 2 is a diagram showing the entire processing and configuration in the content-number-limited content generation device and the content-number-limited content reproduction device. FIG. This embodiment will be described with reference to FIGS.
In the present embodiment, the encryption is performed using the same public key encryption (for example, RSA public key encryption by RSA) in which the key to be encrypted and the key to be decrypted are different from each other. A description will be given using an example in which the common key encryption is combined and the common key itself used for the encryption is further encrypted by another key using a key encryption key (KEK) method. Further, in the present embodiment, it is assumed that the public key encryption algorithm of the content provider and the algorithm of the public key encryption generated by the purchaser in the dedicated playback software are the same, but different public key encryption algorithms are used. May be.
[0019]
The encrypted content server 1 serving as a content encryption unit includes an encryption unit 13 that encrypts the content 12 with a common key 11 using a different common key 11 for each content 12, and the encrypted content 12 is encrypted. It is stored in the content server 1. The encrypted content server 1 stores in advance a plurality of contents 12 by encrypting them with a common key 11 that differs for each content 12 in advance.
[0020]
Typical symmetric key cryptosystems include DES (Date Encryption Standard), Triple-DES, IDEA (International Data Encryption Algorithm), FEAL (Fast Data Engment, etc., which are common in EFAL and Fast Data Engment, etc.). Any method can be used as long as key encryption is used.
[0021]
An encryption key server 2 serving as a key encryption means encrypts a common key 11 obtained by encrypting a content 12 with a secret key of a content provider (hereinafter, a content provider secret key) in the encrypted content server 1. It has means 14-1 and an encrypting means 14-2 for encrypting with the purchaser's public key (hereinafter, the purchaser's public key).
[0022]
The common key 11 is temporarily stored in the encryption key server 2 after being encrypted by the encryption means 14-1 using the content provider private key. After the contract with the content purchaser (hereinafter referred to as the purchaser) ends, the common key 11 is transmitted from the content purchaser terminal 10 via the network and the gateway (hereinafter referred to as the GW) 8 by the encryption means 14-2. It is encrypted with the coming buyer's public key.
[0023]
In this embodiment, the order of encryption is such that the common key 11 is encrypted with the secret key of the content provider and then further encrypted with the purchaser's public key as shown in FIG. However, as shown in FIG. 3B, after the contract is over, the common key 11 may be encrypted with the purchaser's public key, and then further encrypted with the secret key of the content provider. The common key 11 of each content 12 encrypted with the secret key of the content provider and the purchaser's public key is stored in the encryption key server 2 again.
The common key 11 and the public key used may be changed at a certain time period. In that case, the encryption key stored in the encryption key server 2 is also changed at the same time.
[0024]
The ticket issuing server 3 issues a license (hereinafter, a ticket) for the number of times that the purchaser can view and is a view number encrypting means and a ticket creating means according to claim 1. The number-of-viewings encryption means 16 encrypts the desired number of views 15 requested by the purchaser at the time of contract with the purchaser's public key. The encrypted desired viewing number 15 is combined with the common key 11 encrypted by the encryption means 14-1 and 14-2, created as a ticket, and stored in the ticket issuing server 3. Various methods are conceivable as a method for creating a ticket, and typical examples are shown in FIGS.
[0025]
First, among the ticket creation methods shown in FIG. 4, a creation method of the number-of-viewings information will be described. The upper limit of the number of times of viewing is predetermined, and the information amount obtained by binarizing the number of times of viewing is always represented by a fixed number of bits. This information may be represented by a numeric ASCII code, or may be text data according to a predetermined format such as XML (extensible Markup Language). Assuming that the number of bits is s, generally, in encryption, the amount of information of the original data is the same as the amount of information after encryption, and therefore the number of bits after encryption is also s.
[0026]
Assuming that the number of desired views sent from the purchaser is n, information representing the number of views from n to 0 is separately encrypted with the purchaser's public key, and these are arranged in order from n and s × (n + 1) Create bit data. Further, the common key (data length k bits) obtained by encrypting the content encrypted with the content provider private key sent from the encryption key server 2 is further encrypted with the purchaser public key. Further, the length of the encrypted common key is also k bits.
[0027]
By connecting the thus-encrypted information of the desired number of times of viewing (hereinafter referred to as encrypted number of times of viewing) and the encrypted common key (hereinafter referred to as the encrypted common key), k + s × (n + 1) -bit data is created. Then, information representing the length of this data (hereinafter, ticket size data) is added to the beginning of the data to create a ticket. The maximum value of the information amount of the data connecting the encrypted number of times of viewing information and the encrypted common key is when n is the upper limit of the number of times of viewing, and when the information amount of the ticket size data at this time is t bits, n Even when is less than or equal to the upper limit of the number of times of viewing, the amount of ticket information can be represented by always representing the ticket size data with t bits and adding it to the beginning. Therefore, the size T of the ticket data is T = s × (n + 1) + t + k. This is the ticket creation method shown in FIG.
[0028]
In the ticket creation method shown in FIG. 5, first, regarding the number of times of viewing, the upper limit of the number of times of viewing is predetermined as in the case of FIG. 4, and the amount of information obtained by binarizing the number of times of viewing is always determined. Shall be represented by the number of bits This information may be represented by a numeric ASCII code or text data according to a predetermined format such as XML. Assuming that the number of bits is s, the amount of information does not change due to encryption, so the number of bits of the encrypted viewing count information is also s. Assuming that the desired number of viewings sent from the purchaser is n, information representing 0 is first encrypted with the purchaser's public key to create s-bit data. Next, information representing 1 is connected to the s-bit data representing 0, and the connected 2s-bit data is encrypted with the purchaser's public key. In this way, up to n are similarly created.
[0029]
In creating the information representing n, the encrypted data of n × s bits and the data representing n are connected, and the data of (n + 1) × s bits is encrypted with the purchaser's public key. The thus-obtained encrypted viewing frequency information and the encrypted common key are connected to generate k + s × (n + 1) -bit data, and k + s × (n + 1) is added to the head of the data as in the case of FIG. Create a ticket by adding ticket size data. The maximum value of the information amount of the ticket is when n is the upper limit of the number of times of viewing, and when the amount of information of the ticket size data at this time is t bits, even when n is less than the upper limit of the number of times of viewing, it is always t bits By representing the ticket size data and adding it to the head, the information amount of the ticket can be represented. In this case, the ticket data size T is T = s × (n + 1) + k + t.
[0030]
The multiplexing device 4 as multiplexing means multiplexes the encrypted content stored in the encrypted content server 1 with the ticket stored in the ticket issuing server 3 to create distribution content.
[0031]
FIGS. 6 and 7 are explanatory diagrams for explaining a multiplexing method performed by the multiplexing device 4. FIG. There are various methods for multiplexing the encrypted contents and the ticket, but the typical one is mentioned.
The example of FIG. 6 is a method of multiplexing by adding a ticket having a data size of T bits before the encrypted content.
The example of FIG. 7 is a method of multiplexing by inserting a ticket having a data size of T bits at a position that is always m bits ahead of the head of the encrypted content data.
[0032]
As shown in FIG. 1, the content server for distribution 5 is the distribution means of claim 1. The distribution content created by the multiplexing device 4 is temporarily stored in the distribution content server 5 and then distributed via the GW 8 and the Internet 9. The Internet 9 and the content provider's intranet 7 are connected via a GW 8, and the connection between the purchaser and the content provider is always performed via the GW 8.
In the present embodiment, the Internet 9 is assumed as the external network. However, any network can be used as long as the network can connect the content provider and the purchaser, such as a telephone connection.
[0033]
The dedicated playback software server 6 serving as playback software storage means stores dedicated playback software for playing back the content, and downloads and provides the dedicated playback software to the purchaser via the Internet 9 according to an instruction from the GW 8. The dedicated playback software incorporates a provider public key in advance and is provided to the purchaser together with the dedicated playback software.
In addition, the dedicated reproduction software can be obtained from a reliable medium such as a CD-ROM or an FD.
[0034]
As described above, in the present embodiment, the viewing number limited content generation device includes the encrypted content server 1, the encryption key server 2, the ticket issuing server 3, the multiplexing device 4, the distribution content server 5, the dedicated reproduction. Each of the software servers 6 is a terminal including an independent processing device, and is connected to each other via an intranet 7 so as to be communicable with each other. However, these servers may be configured by programs and terminal devices having respective functions incorporated in a large-sized workstation or the like.
[0035]
Next, the configuration of the content purchaser will be described. As shown in FIG. 1 and FIG. 2, the content purchaser side is constituted by a PC 10 which is a content purchaser terminal. It is assumed that content-specific playback software has been downloaded from the dedicated playback software server 6 to the PC 10 in advance. All viewing of the content is performed in the PC 10 by the operation of the content-specific reproduction software.
Of course, it is also possible to configure the content purchaser terminal as a dedicated playback device instead of a PC. Even in this case, a function for incorporating and operating the content-specific reproduction software is necessary.
[0036]
The separating device 21 serving as a separating unit separates the distributed content into the encrypted content 29 and the ticket 30 in the PC 10.
FIGS. 8 and 9 are diagrams showing a method of extracting the ticket 30 from the content in which the dedicated reproduction software is multiplexed in the separation device 21.
The example shown in FIG. 8 shows how to take out a ticket when the multiplexing shown in FIG. 6 is performed. If the encrypted ticket 30 is added to the head of the encrypted encrypted content 29 and multiplexed, the dedicated playback software reads the first t bits of the distribution content received, and writes the content written therein. Is the information amount of the ticket. Assuming that the written content is T, T bits are extracted from the beginning, the extracted T bits are used as the encrypted ticket 30, and the remaining data is used as the encrypted content 29.
[0037]
The example shown in FIG. 9 shows how to take out the ticket 30 when the multiplexing shown in FIG. 7 is performed. In order to take out the encrypted ticket 30, a position which is advanced by m + 1 bits which is a predetermined value from the head of the received distribution content is set as the head of the ticket 30. From here, t bits are read, and the content written there is used as the information amount of the ticket. If the written content is T, counting T bits from the head of the ticket and extracting T bits. The extracted T bits are used as an encrypted ticket 30, and the remaining data is used as an encrypted content 29.
[0038]
As shown in FIG. 2, the dividing device 23 is a dividing means according to claim 3, and further divides the separated ticket 30 into encrypted viewing count information 31 and an encrypted common key 32.
The dividing device 23 extracts the encrypted viewing frequency information 31 and the encrypted common key 32 from the ticket 30 extracted by the separating device 21 from the multiplexed distribution content. In both the case of the ticket created by the ticket creation method described in FIG. 4 and the case of the ticket created by the ticket creation method described in FIG. 5, k bits counted from the end are extracted as the encryption common key 32 and the remaining Is the encrypted viewing frequency information 31.
[0039]
The decryption means 24 as the number-of-viewings information decryption means decrypts the encrypted number-of-viewings information 31 divided by the dividing device 23 into the number-of-viewings information 33 with the purchaser's private key. The purchaser's private key is generated together with the purchaser's public key in the dedicated playback software at the time of the contract, and is incorporated in the dedicated playback software.
[0040]
The decrypting means 25-1 and 25-2, which are the common key decrypting means, decrypt the encrypted common key 32 divided by the dividing device 23 into the common key 11.
First, the encrypted common key 32 of k bits counted from the end divided by the dividing device 23 is decrypted by the purchaser private key using the decrypting means 25-1. Subsequently, the content is decrypted with the content providing side public key using the decrypting means 25-2. The content providing side public key is provided by being incorporated in dedicated playback software. As a result of the two decryptions, a common key 11 is obtained.
[0041]
The decoding means 26 and the reproducing device 27 are the reproducing means of claim 3. The decrypting means 26 decrypts the encrypted content 29 separated by the separating device 21 into the content by using the decrypted common key 11. The reproducing device 27 confirms that the decrypted content is legitimate provided by the content providing side by being correctly decrypted in this manner, and reproduces the content under the control of the reproduction control device 28.
[0042]
The reproduction control device 28 serving as the reproduction control device refers to the viewing frequency information 33 decoded by the decoding device 24 to permit the reproduction of the content by the reproduction device 27 and to execute the reproduction of the content by the reproduction device 27 every time. Next, control is performed by reducing the number of times of viewing / listening information 33 by one. When the number-of-viewings information 33 becomes 0, the reproduction of the content by the reproduction device 27 is prohibited.
[0043]
The processing performed by the dedicated reproduction software on the PC 10 of the content purchaser will be described again with reference to the flowcharts of FIGS. FIG. 10 shows processing in the case where a ticket created by the ticket creation method of FIG. 4 is attached to distribution content.
First, in step S101, k bits counted from the end are extracted as data of the common key 11 (here, the encrypted common key 32). In step S102, the k bits are decrypted with the purchaser private key and the content providing public key. As a result, the common key 11 is obtained in step S103, and the process proceeds to step S109.
[0044]
In step S104, the portion from the (t + 1) th bit to the (t + 1 + s) th bit is counted from the beginning of the remaining data. Next, in step S105, this is decrypted with the purchaser's private key. Next, in step S106, it is determined whether the decrypted data is 0. If this data is 0 (YES), the process proceeds to step S107 to stop the reproduction.
[0045]
If the decrypted data is a non-zero value in step S106 (NO), the reproduction process is continued in step S108, and the content is decrypted and reproduced using the common key 11 obtained in step S103 in step S109. When the reproduction is completed in step S110 and the end button of the dedicated reproduction software is pressed, (t + s) bits are deleted from the head of the ticket in step S111, and in step S112, t + k + s × n bits indicating t + k + s × n bits are added to the head of the ticket. The bit data is added, and this data is overwritten on the old ticket as a new ticket in step S113. After the overwriting is completed, the dedicated reproduction software ends in step S115.
[0046]
FIG. 11 shows a process performed when a ticket created by the method described with reference to FIG. 5 is attached to distribution content.
As in the case of FIG. 10, first, in step S201, k bits counted from the end are extracted as data of the common key 11 (here, the encrypted common key 32). In step S202, the k bits are decrypted with the purchaser secret key and the content providing side public key. As a result, the common key 11 is obtained in step S203, and the process proceeds to step S209.
In step S204, the data from the (t + 1) th bit to the end counted from the beginning of the remaining data is extracted. Next, in step S205, this is decrypted with the purchaser's private key. Next, in step S206, it is determined whether or not the first s bit of the decoded data is 0. If this data is 0 (YES), the process proceeds to step S207 to stop the reproduction.
[0047]
If the decrypted data has a value other than 0 in step S206 (NO), the reproducing process is continued in step S208, and the content is decrypted and reproduced in step S209 using the common key 11 obtained in step S203. When the reproduction is completed in step S210 and the end button of the dedicated reproduction software is pressed, the (t + s) bits are deleted from the head of the ticket in step S211 and in step S212, t + k + s × n bits representing t + k + s × n bits are added to the head of the ticket. Bit data is added, and this data is overwritten on the old ticket as a new ticket in step S213. After the overwriting is completed, in step S215, the dedicated reproduction software ends.
[0048]
FIG. 12 is a sequence chart again showing the content distribution processing in the viewing number limited content generation device and the viewing number limited content reproduction device of the present invention described above. In the figure, the part shown by a solid line is an essential sequence, and the part shown by a dotted line is a sequence incorporated as needed.
First, a purchaser who does not have the content-specific playback software installed on the PC 10 accesses the content provider to download the dedicated playback software, and makes a request for the dedicated playback software.
[0049]
The access point on the content provider side is the GW 8, and the GW 8 responds to the purchaser regardless of any access. The GW 8 accesses the dedicated playback software server 6 and gives an instruction to download the dedicated playback software. Thereby, the dedicated reproduction software is downloaded to the purchaser's terminal PC10. From the beginning, the download process of the dedicated reproduction software is not required for the purchaser who has the dedicated reproduction software installed on the PC 10 or the purchaser who has the dedicated reproduction device.
[0050]
Next, the purchaser makes a content browsing request. All subsequent operations are performed by the PC 10. When a browsing request is made, the GW 8 instructs the encrypted content server 1 to download a list display. Then, a content list is displayed on the PC 10. The purchaser selects the content to be viewed from the content list, and requests the content from the content provider. At this time, the purchaser provides the content provider with the purchaser's desired viewing count 15 which is the number of times the purchaser can view the content desired by the purchaser, and the purchaser's public key created in the dedicated playback software. And stored in the GW 8.
[0051]
This purchaser's public key is a public key generated in the exclusive playback software of the purchaser at the time of the contract, and after a formal contract between the purchaser and the content provider, this purchaser's public key becomes the content provider The GW 8 sends the received purchaser public key to the encryption means 14-2 in the encryption key server 2. At the same time, the purchaser's PC 10 incorporates the purchaser's private key into the dedicated playback software.
Thereafter, the GW 8 is used by the encryption key server 2 to encrypt the contracted content and is encrypted in advance with the content provider private key. Then, it instructs the common key 11 encrypted with the purchaser public key to be sent to the ticket issuing server 3, and the ticket issuing server 3 receives the encrypted common key 11.
[0052]
Next, the GW 8 sends the purchaser's desired viewing count 15 and the purchaser's public key desired by the purchaser to the ticket issuing server 3 and issues an instruction to issue a ticket that allows viewing the desired number of times. Thereafter, the ticket issued by the ticket issuing server 3 is sent to the multiplexing device 4. Further, the GW 8 instructs the encrypted content server 1 in which the encrypted content is stored in advance, to transmit the content desired by the purchaser to the multiplexer 4. Thereafter, the content and the ticket encrypted in the multiplexer 4 are multiplexed. The multiplexed content is transmitted to the distribution content server 5 and stored as distribution content. After the distribution content is transmitted to the distribution content server 5, the GW 8 issues an instruction to distribute the distribution content to the distribution content server 5. Then, the content is distributed to the PC 10.
[0053]
According to the embodiment of the present invention, the content is encrypted in advance, and the time taken by the content providing device after the contract is obtained by encrypting the encrypted common key with the purchaser's public key, This is the processing time for multiplexing with the encrypted content. Even if a large number of buyers access at the same time, the load on the device is much less than when encrypting the content for each access.
Also, since the ticket required when playing back the content includes information on the number of times of viewing, even if the user wants to view the content multiple times, the content purchaser does not need to contract with the content provider each time. It is only necessary to purchase a desired number of tickets in advance. Therefore, the burden on both the content provider and the content purchaser is reduced, and the load on the network is also reduced.
[0054]
Further, the ticket differs for each content, and even if an attempt is made to reproduce content that does not correspond to the ticket, the content other than the content cannot be decrypted with the common key in the ticket, so that other content cannot be reproduced. Therefore, the content purchaser needs to inform the content provider together with the content to be viewed and the desired number of times of viewing the content. For this reason, the content provider can accurately grasp information on which content is viewed by which buyer and how much. By analyzing this information, it is possible to accurately obtain information about the type and content of the content required by the user, and to provide content suitable for the needs of the purchaser.
[0055]
Furthermore, since the public key of the content provider is pre-installed in the dedicated playback software, anyone can access the dedicated playback software of the authorized content provider to obtain it. On the other hand, since the secret key of the content provider is not publicly disclosed, only the authorized content provider knows, and the unauthorized content provider cannot know.
[0056]
Further, the method of multiplexing the key data with the encrypted content can only be known by the legitimate content provider, so that the content data provided by an unauthorized content provider impersonating the legitimate content provider can be used. Encryption and encryption are not performed correctly. Therefore, the dedicated playback software cannot take out and decrypt the encrypted key data, and as a result, the content cannot be played back correctly. Therefore, if the content can be reproduced by the dedicated reproduction software, the purchaser can confirm that the content is provided by an authorized content provider.
[0057]
Also, since the multiplexed content stored in the purchaser's PC is encrypted, even if the purchaser copies the content data and passes it to a third party, the third party's dedicated playback software Does not incorporate the purchaser's private key required to decrypt the passed content, and therefore cannot reproduce the content. For this reason, reproduction is impossible only by a legitimate contractor, and illegal use can be prevented.
[0058]
In the present invention, a ticket is multiplexed from the content provider to the content, and the multiplexed data is downloaded. However, a ticket used to control viewing by authenticating the content provider and the purchaser. Only the content is downloaded from the content provider, and the content is distributed by various media such as CD-ROM and DVD which can be played by the dedicated playback software, or a plurality of content servers are set up on the Internet, and anyone can freely download or stream the content. It is also possible to watch. It is also possible for the purchasers to transmit and receive content data. In such a case, the only thing purchased from the content provider is the ticket. Even if the ticket is copied by a third party, the third party's dedicated playback software extracts the common key from the ticket. The content cannot be reproduced because the purchaser's private key, which is required at that time, is not incorporated.
[0059]
Therefore, unless the ticket is purchased, reproduction becomes impossible, and illegal use can be prevented. In this way, the content is separated from the ticket that controls authentication and the number of times of viewing, so that the content can be freely downloaded or users can copy the content that they have and copy each other. Can reduce the burden on the device of the content provider, and at the same time, it is possible to distribute the load on the network.
In the present invention, the public key is exchanged only between the content provider and the purchaser. However, the public key guaranteed by using a certificate by a third party such as a certificate authority is used. It is also possible to use.
[0060]
The above description has mainly described the limited-viewing-contents generating apparatus and the limited-playing-contents reproducing apparatus of the present invention. The present invention is also directed to a program for distributing and reproducing content with a limited number of times.
[0061]
【The invention's effect】
As described above, according to the viewing count limited content generation device according to claim 1 of the present invention, the content can be encrypted in advance, so that even if many purchasers access at the same time, Highly confidential content distribution can be performed without imposing a burden on the content providing device. Also, since a ticket including the number of times of viewing is issued, it is possible to limit the number of times of viewing of the purchaser. Further, since the purchaser's private key is required for decrypting the encrypted common key, there is an advantage that the content is not illicitly used by a third party. In addition, by issuing a ticket including the number of times of viewing, information such as the desire for the content and the viewing status can be accurately collected, and the content that meets the needs can be provided.
[0062]
According to the viewing number limited content generation device of the present invention, the exclusive reproduction software can be distributed to the purchaser as needed, and the public key of the content provider and the purchaser secret key are included in the reproduction software. Since it is possible to include a method of creating a content, a highly confidential content distribution can be performed without the purchaser being particularly conscious. Furthermore, the purchaser creates a purchaser's public key in the dedicated playback software, and incorporates the purchaser's private key into the dedicated playback software, which prevents content from being played without the dedicated playback software, thus preventing unauthorized use. can do.
[0063]
According to the content-reproduction apparatus for limiting the number of times of viewing according to claim 3 of the present invention, the public key of the content provider and the secret key of the purchaser are used for decrypting the encrypted common key. Authentication can be performed, and it can be confirmed that the content is worth paying a regular fee. Also, since the number of times of viewing is included in the ticket, if the desired number of times of viewing is presented in advance, it is not necessary to make a contract with the content provider each time, and the burden on the purchaser can be reduced.
[0064]
Further, according to the viewing count limited content distribution method according to claim 4 of the present invention, the content is distributed in advance after encrypting the content. Highly confidential content distribution can be performed without imposing a burden on the providing apparatus. In addition, since the ticket including the number of times of viewing is distributed simultaneously, it is possible to limit the number of times of viewing of the purchaser. Further, since the purchaser's private key is required for decrypting the encrypted common key, there is no possibility that the contents are illegally used by a third party. In addition, by issuing a ticket including the number of times of viewing, information such as the desire for the content and the viewing status can be accurately collected, so that the content that meets the needs can be provided.
[0065]
Further, according to the viewing number limited content distribution program according to claim 5 of the present invention, the content can be encrypted in advance, and even if a large number of buyers access at the same time, the content providing A program that can deliver highly confidential content without burdening the device can be obtained. Also, a ticket including the number of times of viewing can be issued by this program, and the number of times of viewing of the purchaser can be limited. Furthermore, if this program is used, the purchaser's private key is necessary for decrypting the encrypted common key, so that there is no risk that the contents will be illegally used by a third party. In addition, by using this program, by issuing a ticket including the number of times of viewing, it is possible to accurately collect information such as the desire for the content and the viewing status, and to provide the content that meets the needs.
[0066]
Further, according to the viewing number limited content reproducing program according to claim 6 of the present invention, the purchaser can authenticate the content provider and can confirm that the content is worth the regular fee. it can. In addition, according to this program, the number of times of viewing can be included in the ticket. By presenting the desired number of times of viewing in advance, it is not necessary to make a contract with the content provider each time, and the burden on the purchaser can be reduced. Can be.
[Brief description of the drawings]
FIG. 1 is a lock diagram illustrating a configuration of a viewing count limited content generation device according to the present invention and peripheral components.
FIG. 2 is a block diagram showing the overall processing and configuration of the viewing number limited content generation device and the viewing number limited content reproduction device according to the present invention.
FIG. 3 is an explanatory diagram showing a method of encrypting a common key according to the present invention.
FIG. 4 is an explanatory diagram of a ticket creation method according to the present invention.
FIG. 5 is an explanatory diagram of a ticket creation method according to the present invention.
FIG. 6 is an explanatory diagram of a multiplexing method according to the present invention.
FIG. 7 is an explanatory diagram of a multiplexing method according to the present invention.
FIG. 8 is an explanatory diagram of a method of separating a ticket from content according to the present invention.
FIG. 9 is an explanatory diagram of a method of separating a ticket from content according to the present invention.
FIG. 10 is a flowchart of processing for separating a common key from a ticket and reproducing the ticket in the present invention.
FIG. 11 is a flowchart of processing for separating a common key from a ticket and reproducing the ticket in the present invention.
FIG. 12 is a sequence chart of content distribution according to the present invention.
[Explanation of symbols]
1 encrypted content server
2 Encryption key server
3 ticket issuing server
4 Multiplexer
5 Content server for distribution
6 Dedicated playback software server
7 content provider intranet
8 GW (gateway)
9 Internet
10 Content purchaser terminals
11 common key
12 Contents
13 Encryption means
14-1, 14-2 Encryption means
15 desired views
16 Encryption means
21 Separation device
23 Splitting device
24 Decoding means
25-1, 25-2 decoding means
26 Decoding means
27 Playback device
28 Playback control device
29 Encrypted content
30 tickets
31 Encrypted viewing count information
32 encryption common key
33 Views information

Claims (6)

In a viewing count limited content generation device that generates a viewing count limited content in which the number of viewing of content such as a moving image and / or a sound is limited to a number desired by a content purchaser,
A content encrypting means for encrypting the content at the stage of creating the content using a different common key for each content to obtain encrypted content, and providing the common key used for encryption by the content encrypting means to the content; Key encrypting means for encrypting with a provider secret key on the side and a purchaser public key provided by the content purchaser to obtain an encrypted common key,
A view count encrypting means for receiving information indicating the desired number of views of the content purchaser, encrypting the information with the purchaser public key to obtain encrypted view count information,
Ticket creation means for creating a ticket for permitting viewing by combining the encrypted common key encrypted by the key encryption means and the encrypted viewing number information encrypted by the viewing number encryption means. When,
A multiplexing unit that multiplexes the encrypted content encrypted by the content encryption unit and the ticket created by the ticket creation unit to be a content for distribution for distribution via a network;
A distribution means for distributing the distribution content created by the multiplexing means via a network. 2. The viewing count limited content generation apparatus according to claim 1, further comprising: playback software storage means for storing dedicated playback software for playing back the distribution content and providing the playback software to the content purchaser. A viewing number limited content reproducing apparatus that reproduces distribution content generated by the viewing number restricted content generating apparatus according to claim 1,
Separating means for separating the distribution content into the encrypted content and the ticket,
Dividing means for dividing the ticket separated by the separating means into the encrypted common key and the encrypted viewing count information;
A viewing number information decrypting means for decrypting the encrypted viewing number information divided by the dividing means with a purchaser private key of the content purchaser,
Common key decryption means for decrypting the encrypted common key divided by the division means with a provider public key previously provided by the content provider and a purchaser private key of the content purchaser;
Using the common key decrypted by the common key decrypting means, the encrypted content separated by the separating means is decrypted to confirm that the content is legitimate from the content providing side, and the decrypted content is reproduced. Playback means,
A playback control means for controlling the number of times the content is played back by the playback means based on the viewing number information decoded by the viewing number information decoding means. In a viewing number limited content distribution method for distributing a content such as a moving image and / or a sound only to the number of times the content purchaser desires,
A content encryption step of encrypting the content at a stage of creating the content using a different common key for each content to obtain an encrypted content,
Information about the number of times that the buyer wants to view the content that he / she wants to purchase, a process for acquiring the buyer's public key,
A key encryption step of encrypting the common key used for encryption in the content encryption step with a provider private key of the content provider and the purchaser public key to form an encrypted common key;
A viewing times encryption process in which the desired viewing times information is encrypted with the purchaser public key to obtain encrypted viewing times information,
A ticket creation step of creating a ticket for permitting viewing by combining the encrypted common key encrypted in the key encryption step and the encrypted viewing number information encrypted in the viewing number encryption step; ,
A multiplexing process of multiplexing the encrypted content encrypted in the content encryption process and the ticket created in the ticket creation process into a content for distribution;
A distribution step of distributing the distribution content obtained by multiplexing in the multiplexing step via a network. In a viewing number limited content distribution program used in a distribution side processing device that distributes content such as a moving image and / or audio via a network, the number of times of viewing limited to the number of times desired by the content purchaser,
A content encryption procedure for encrypting the content at a stage of creating the content using a common key different for each content to make the content encrypted;
A key encryption procedure in which the common key used for encryption in the content encryption procedure is encrypted with a provider private key and a purchaser public key on the content provider side to form an encrypted common key;
A view count encryption procedure in which the content purchaser's desired view count information is encrypted with the purchaser public key to obtain encrypted view count information;
A ticket creation step of creating a ticket as a view permission message by combining the encrypted common key encrypted in the key encryption procedure and the encrypted view count information encrypted in the view count encryption procedure,
A multiplexing procedure in which the encrypted content encrypted in the content encryption procedure and the ticket created in the ticket creation procedure are multiplexed to be distribution content for delivery via a network,
A distribution procedure for distributing, via a network, the distribution content obtained by multiplexing in the multiplexing procedure, the processing apparatus executes the distribution procedure. In the content reproduction program used in the processing device of the purchaser side, which is distributed via the network, the number of times of viewing of the content such as the moving image and / or the audio is limited to the number of times desired by the content purchaser, Separation procedure for separating the content for distribution, which is encrypted and distributed as many times as desired by the content purchaser, into the encrypted content and the ticket,
A dividing step of dividing the ticket separated in the separating step into an encrypted common key and encrypted viewing count information;
A viewing number information decrypting step of decrypting the encrypted viewing number information divided by the dividing procedure with a purchaser private key of the content purchaser,
A common key decryption step of decrypting the encrypted common key divided in the division step with a provider public key and a purchaser private key of the content purchaser provided in advance from a content provider;
A playback procedure for decrypting the encrypted content separated in the separation procedure by the common key decrypted in the common key decryption procedure, confirming that the encrypted content is legitimate from the content providing side, and playing back the content,
A viewing number-restricted content reproduction program, which causes a processing device to execute a reproduction control procedure for controlling the number of reproductions of reproducing a content by the reproduction procedure, based on the number-of-views information decoded in the viewing number information decoding procedure.

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