JP2008072417A - Content distribution device for digital broadcasting, content authentication system for digital broadcasting, content authentication method for digital broadcasting, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a content distribution device for digital broadcasting that achieves safe message-authentications in digital terrestrial broadcasting. <P>SOLUTION: A public key and a secret key are generated so as to transmit the generated public key to a receiving terminal. On the other hand, it is composed to generate a hash packet which calculates a hash value of a packet corresponding to an arbitrary number of digital broadcasting contents to be distributed so as to store it. It is also composed to generate a signature packet for storing a signature with respect to the hash value of the hash packet. The hash packet and the signature packet are inserted between packets of each digital broadcasting content at an arbitrary interval so as to generate a distribution packet. The generated distribution packet is transmitted to the receiving terminal. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a digital broadcast content distribution apparatus, a digital broadcast content authentication system, a digital broadcast content authentication method, and a program.

  Currently, the mainstream of television broadcasting is based on analog signals. At the end of 2003, so-called terrestrial digital broadcasting based on digital signals started in some areas, and in 2006 it was expanded nationwide. Has been decided to be. Under such circumstances, users' interest in terrestrial digital broadcasting is increasing. At present, terrestrial digital broadcasting for mobile terminals called so-called one-segment broadcasting in mobile terminals is also in practical use.

In this way, the broadcasting industry is rapidly progressing in the direction of digitalization, and the standards are being prepared (see, for example, Non-Patent Documents 1 to 3). In response to this situation, small-scale broadcasting services such as regional broadcasting stations are also being considered.
Data broadcasting encoding and transmission system for digital broadcasting, standard ARIB STD-B24 4.0 edition, Japan Radio Industry Association, revised on February 5, 2004 Access control method and standard for digital broadcasting ARIB STD-B25 4.1 Edition The Japan Radio Industry Association, revised on June 5, 2003 Design Manual for FM Broadcast Evaluation Receiver Technical Data ARIB TR-B11 1.0 Edition The Japan Radio Industry Association, February 2, 1999

  However, instead of the conventional analog system, when television broadcasting becomes a digital system, a third party that is not the original broadcast station impersonates the original broadcast station and distributes illegal content using inexpensive equipment. There is also a high risk of However, the standard mentioned above mentions the functions related to error correction by codes, and does not mention anything about the distribution of illegal contents mentioned above, and secure message authentication in terrestrial digital broadcasting. There is a problem that it is not secured at all.

  Therefore, the present invention has been made in view of the above-described problems, and a digital broadcast content distribution apparatus, a digital broadcast content authentication system, and a digital broadcast content authentication that can realize secure message authentication in terrestrial digital broadcasting. An object is to provide a method and a program.

The present invention proposes the following items in order to solve the above-described problems.
(1) The present invention is a digital broadcast content distribution device that distributes digital broadcast content to a receiving terminal in a packet generation unit that generates a public key and a secret key (for example, the public key / secret of FIG. 2). A key generation unit 11), a public key transmission unit that transmits the public key generated by the key generation unit to the receiving terminal (for example, the verification information distribution unit 13 in FIG. 2), and any distribution Hash packet generation means (for example, equivalent to the hash packet generation unit 14 in FIG. 2) for generating a hash packet for calculating and storing a hash value of a packet corresponding to the number of digital broadcast contents, and a hash value of the hash packet Signature packet generation means (for example, corresponding to signature packet generation unit 15 in FIG. 2) for generating a signature packet for storing a signature for Distribution packet generation means (for example, corresponding to the packet insertion unit 16 in FIG. 2) for generating a distribution packet by inserting a packet and a signature packet between the digital broadcast content packets at an arbitrary interval, Proposed is a digital broadcast content distribution apparatus comprising distribution packet transmission means (for example, corresponding to the packet distribution unit 17 in FIG. 2) for transmitting a distribution packet to the receiving terminal.

  According to this invention, the key generation unit generates a public key and a secret key, and the public key transmission unit transmits the generated public key to the receiving terminal. On the other hand, the hash packet generation means generates a hash packet for calculating and storing a hash value of a packet corresponding to an arbitrary number of contents for digital broadcasting to be distributed, and the signature packet generation means generates a signature for the hash value of the hash packet. Generate a signature packet to be stored. Then, the distribution packet generation unit inserts the hash packet and the signature packet between the digital broadcast content packets at arbitrary intervals, generates a distribution packet, and transmits the distribution packet generated by the distribution packet transmission unit to the receiving terminal. .

  Accordingly, when the receiving terminal has a function of detecting falsification of a packet corresponding to digital broadcast content distributed and a function of verifying the validity of a hash packet, secure message authentication can be realized. On the other hand, even when the receiving terminal does not have the above function, define a hash packet and a signature packet independently of existing packets and insert these packets so as not to affect the existing packets. Therefore, it is possible to receive conventional terrestrial digital broadcasting while maintaining compatibility of specifications.

  (2) In the digital broadcast content distribution apparatus according to (1), the hash packet generation means (for example, equivalent to the hash packet generation unit 14 in FIG. 2) distributes a packet corresponding to the digital broadcast content. A digital broadcast content distribution apparatus has been proposed in which the number of packets for calculating a hash value is varied according to the interval.

  According to the present invention, the hash packet generation means varies the number of packets for calculating a hash value in accordance with the distribution interval of packets corresponding to digital broadcast content. That is, since the number of packets for calculating the hash value can be varied according to the free state of the existing packet, it is possible to generate the hash packet while taking into account control within the transmission bandwidth rate. In addition, since a plurality of existing packets are collected and one hash packet is generated, it is possible to prevent an unnecessary increase in data capacity.

  (3) According to the present invention, in the digital broadcast content distribution apparatus of (1) or (2), the hash packet generation means (for example, equivalent to the hash packet generation unit 14 of FIG. 2) The packet corresponding to the broadcast content is divided into an arbitrary number of packet groups, and the hash value of the preceding packet group and the hash value of the subsequent packet group are multiplexed to sequentially calculate a plurality of hash values, and the calculation A digital broadcast content distribution apparatus has been proposed in which an overall hash value is calculated and stored for a plurality of hash values.

  According to this invention, the hash packet generation means divides a packet corresponding to an arbitrary number of digital broadcast contents into an arbitrary number of packet groups, and the hash value of the preceding packet group and the hash value of the subsequent packet group Are sequentially calculated to calculate a plurality of hash values, and the entire hash value is calculated and stored for the calculated plurality of hash values.

  That is, in the case of broadcast distribution, unlike other data distribution, packet re-transmission cannot be performed when a packet loss occurs. Therefore, by multiplexing the hash value of another hash packet with the hash value of one hash packet and including the hash value of one hash packet in the hash value of the other hash packet, loss resistance against packet loss is improved. Can be increased.

  (4) The present invention relates to the digital broadcast content distribution apparatus of (3), wherein the hash packet generation means (e.g., corresponding to the hash packet generation unit 14 of FIG. 2) The entire hash value in the packet is stored according to a predetermined redundancy, and the signature packet generation means (for example, equivalent to the signature packet generation unit 15 in FIG. 2) does not satisfy the predetermined redundancy in the signature packet. A hash value calculated by combining an entire hash value in a hash packet, an entire hash value in a hash packet that is not stored in the signature packet as it is, an entire hash value in a hash packet that does not satisfy the predetermined redundancy, and the hash value The entire hash packet that is not directly stored in the signature packet A signature value signed with a private key generated by the key generation means (e.g., corresponding to the public key / private key generation unit 11 in FIG. 2). The digital broadcast content distribution apparatus according to claim 3, wherein the digital broadcast content distribution apparatus is stored.

  According to this invention, the hash packet generation means stores the entire hash value in each hash packet for a plurality of hash packets according to a predetermined redundancy, and the signature packet generation means stores the signature packet in the signature packet. The hash value calculated by combining the entire hash value in the hash packet that does not satisfy the predetermined redundancy, the entire hash value in the hash packet that is not directly stored in the signature packet, and the entire hash packet that does not satisfy the predetermined redundancy And the hash value calculated by combining the entire hash value in the hash packet that is not stored in the signature packet as it is, and the signature value signed with the secret key generated by the key generation means is stored.

  Accordingly, since the entire hash value in each hash packet is stored according to a predetermined redundancy, loss tolerance against packet loss can be increased. In addition, since the signature is performed by combining the hash value calculated by combining the entire hash value in the hash packet not stored in the signature packet as it is and the hash value calculated by combining the entire hash value in the hash packet not satisfying the predetermined redundancy, Each hash packet can be checked independently.

  (5) The present invention is a digital broadcast content authentication system comprising a broadcast station provided with the digital broadcast content distribution device of (1) to (4) and a receiving terminal that receives the distributed digital broadcast content. The receiving terminal receives a public key receiving means (for example, corresponding to the verification information receiving unit 24 in FIG. 3) and a distribution packet receiving means (for example, FIG. 3) that receives the distribution packet. A packet receiving unit 21), a hash value of a packet corresponding to the received arbitrary number of digital broadcast contents, and the calculated hash value and a hash value stored in the received hash packet. Hash value verification means (for example, equivalent to the hash value verification unit 22 in FIG. 3) to be verified, and a hash value calculated from the received hash packet Signature verification means (for example, corresponding to the signature verification unit 23 in FIG. 3) that verifies the validity of the signature by using the received public key and collating with the hash value stored in the signature packet; A content authentication system for digital broadcasting, comprising:

  According to the present invention, for the digital broadcast content distribution apparatus of (1) to (4), the public key receiving means in the receiving terminal receives the public key, and the distribution packet receiving means receives the distribution packet. Then, a hash value of a packet corresponding to an arbitrary number of digital broadcast contents received by the hash value verification unit is calculated, the calculated hash value is compared with the hash value stored in the received hash packet, and the signature is The verification means verifies the hash value calculated from the received hash packet and the hash value stored in the signature packet, and verifies the validity of the signature using the received public key.

  Therefore, since it is possible to detect falsification of the packet by the hash value verification unit and to verify the validity of the hash packet by the signature verification unit, it is possible to realize safe message authentication.

  (6) The present invention is a digital broadcast content authentication method in a digital broadcast content authentication system comprising a broadcast station that distributes digital broadcast content in packets and a receiving terminal that receives the distributed digital broadcast content. The broadcasting station generates a public key and a private key (for example, step S101 in FIG. 6), and a second step (for example, transmits the generated public key to the receiving terminal (for example, Step S102 in FIG. 6), and a third step (for example, Step S103 in FIG. 6) for generating a hash packet for calculating and storing a hash value of a packet corresponding to an arbitrary number of digital broadcast contents to be distributed; A fourth step of generating a signature packet storing a signature for the hash value of the hash packet (for example, Step S104 in FIG. 6) and a fifth step (for example, step in FIG. 6) of inserting the hash packet and the signature packet between the digital broadcast content packets at arbitrary intervals to generate a distribution packet. S105), a sixth step of transmitting the generated distribution packet to the receiving terminal (for example, step S106 of FIG. 6), a seventh step of receiving the public key by the receiving terminal, and the distribution An eighth step of receiving a packet; a hash value of a packet corresponding to the received arbitrary number of contents for digital broadcasting; a hash value stored in the received hash packet; Is calculated from the received hash packet and the ninth step (eg, step S107 in FIG. 6). A tenth step (for example, steps S108 and S109 in FIG. 6) for verifying the validity of the signature using the received public key, while comparing the hash value with the hash value stored in the signature packet; , And a digital broadcast content authentication method characterized by comprising:

  According to the present invention, the broadcasting station generates a public key and a secret key, and transmits the generated public key to the receiving terminal. In addition, a hash packet for calculating and storing a hash value of a packet corresponding to an arbitrary number of digital broadcast contents to be distributed is generated, a signature packet for storing a signature for the hash value of the hash packet is generated, and a hash packet And a signature packet are inserted between digital broadcast content packets at arbitrary intervals to generate a distribution packet. Then, the generated distribution packet is transmitted to the receiving terminal. On the other hand, the receiving terminal receives the public key and the distribution packet, calculates the hash value of the packet corresponding to the arbitrary number of digital broadcast contents received, and stores the calculated hash value and the received hash packet. Against the hash value. Further, the hash value calculated from the received hash packet is compared with the hash value stored in the signature packet, and the validity of the signature is verified using the received public key.

  Therefore, secure message authentication in terrestrial digital broadcasting can be realized by detecting packet tampering and validating the hash packet.

  (7) According to the present invention, authentication of digital broadcast content in a digital broadcast content authentication system comprising a broadcast station that distributes digital broadcast content in packets and a receiving terminal that receives the distributed digital broadcast content is performed on a computer. A program for executing the program, wherein the broadcasting station generates a public key and a private key (for example, step S101 in FIG. 6), and transmits the generated public key to the receiving terminal. A second step (for example, step S102 in FIG. 6), and a third step (for example, generating a hash packet for calculating and storing a hash value of a packet corresponding to an arbitrary number of contents for digital broadcasting to be distributed) , Step S103 in FIG. 6 and a signature for storing a signature for the hash value of the hash packet. A fourth step of generating a packet (for example, step S104 in FIG. 6), and inserting the hash packet and the signature packet between packets of the digital broadcast content at an arbitrary interval to generate a distribution packet 5 (for example, step S105 in FIG. 6), a sixth step for transmitting the generated distribution packet to the receiving terminal (for example, step S106 in FIG. 6), and the receiving terminal using the public key A seventh step of receiving, an eighth step of receiving the distribution packet, and calculating a hash value of a packet corresponding to the received arbitrary number of contents for digital broadcasting, and receiving the calculated hash value A ninth step (for example, step S107 in FIG. 6) for collating the hash value stored in the hash packet; A tenth step (for example, verifying the validity of the signature by using the received public key and comparing the hash value calculated from the received hash packet with the hash value stored in the signature packet) A program for causing a computer to execute steps S108 and S109) of FIG. 6 is proposed.

  According to the present invention, the broadcasting station generates a public key and a secret key, and transmits the generated public key to the receiving terminal. In addition, a hash packet for calculating and storing a hash value of a packet corresponding to an arbitrary number of digital broadcast contents to be distributed is generated, a signature packet for storing a signature for the hash value of the hash packet is generated, and a hash packet And a signature packet are inserted between digital broadcast content packets at arbitrary intervals to generate a distribution packet. Then, the generated distribution packet is transmitted to the receiving terminal. On the other hand, the receiving terminal receives the public key and the distribution packet, calculates the hash value of the packet corresponding to the arbitrary number of digital broadcast contents received, and stores the calculated hash value and the received hash packet. Against the hash value. Further, the hash value calculated from the received hash packet is compared with the hash value stored in the signature packet, and the validity of the signature is verified using the received public key.

  Therefore, secure message authentication in terrestrial digital broadcasting can be realized by detecting packet tampering and validating the hash packet.

  According to the present invention, packet tampering detection and the validity of a hash packet can be verified. Therefore, there is an effect that an unauthorized third party impersonation in terrestrial digital broadcasting can be detected and secure message authentication can be realized.

  In addition, according to the present invention, there is an effect that resistance against packet loss can be provided by multiplexing the hash value of a hash packet with the hash value of another hash packet.

  Furthermore, according to the present invention, since the hash packet and the signature packet are defined independently of the existing transmission packet in the terrestrial digital broadcasting, and the hash packet and the signature packet are inserted in the gap between the existing transmission packets, the receiving terminal Regardless of the function, the compatibility of specifications can be maintained.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Note that the constituent elements in the present embodiment can be appropriately replaced with existing constituent elements and the like, and various variations including combinations with other existing constituent elements are possible. Therefore, the description of the present embodiment does not limit the contents of the invention described in the claims.

  In addition, the present invention is a feature of terrestrial digital broadcasting. 1) Packet loss cannot be detected explicitly. 2) Data is transmitted and received in packet units. 3) A one-way data distribution service from a broadcasting station to a receiving terminal. 4) The same content is distributed simultaneously to all users. 5) Since real-time processing is premised on both the transmission and reception sides, secure message authentication in digital broadcasting is realized while considering various characteristics such as the need to minimize the data size to be buffered.

<Configuration of distribution packet>
With reference to FIG. 1, the configuration of a distribution packet in conventional digital broadcasting and the configuration of a distribution packet in the present embodiment will be described.
As shown in FIG. 1A, the distribution packets in the conventional digital broadcasting are TS (Transport Stream) packets (indicated as TSP in the figure) are randomly arranged in time series according to the distribution timing. .

  On the other hand, as shown in FIG. 1B, the distribution packet in the present embodiment has a hash packet (shown as hash P in the figure) and a signature packet (signed in the figure) in a gap between TS packets in conventional digital broadcasting. (P and display) are inserted.

  Here, the hash packet is a packet that stores the hash value of the TS packet, and the signature packet is a packet that stores a signature for the hash value. In this embodiment, for each TS packet, a hash value is calculated for an arbitrary number of TS packets, and the calculated hash value is stored in the hash packet.

  In addition, a signature is performed on a hash value calculated from a plurality of hash packets, and the signature is stored in the signature packet. The hash packet is used for detecting alteration of the packet, and the signature packet is used to prove the validity of the hash packet.

<Configuration of digital broadcast content distribution device>
The configuration of the digital broadcast content distribution apparatus will be described with reference to FIG.
As shown in FIG. 2, the digital broadcast content distribution apparatus includes a public key / private key generation unit 11, a public key certificate reception unit 12, a verification information distribution unit 13, a hash packet generation unit 14, and a signature packet. The generation unit 15, the packet insertion unit 16, and the packet distribution unit 17 are configured.

  The public key / private key generation unit 11 generates a public key for the receiving terminal to verify the validity of the signature and a secret key used to generate a signature value in the signature packet. The public key certificate receiving unit 12 receives a public key certificate issued from a certificate authority, and the receiving terminal can verify the validity of the public key using the public key certificate. The verification information distribution unit 13 distributes the public key generated by the public key / private key generation unit 11 and the public key certificate received by the public key certificate reception unit 12 from the certificate authority to a plurality of receiving terminals.

  The hash packet generation unit 14 generates a hash packet for calculating and storing a hash value of a packet corresponding to an arbitrary number of contents for digital broadcasting to be distributed. The signature packet generation unit 15 generates a signature packet that stores a signature for the hash value of the hash packet. The packet insertion unit 16 inserts the hash packet generated by the hash packet generation unit 14 and the signature packet generated by the signature packet generation unit 15 into the distribution gap of the existing TS packet, and generates a distribution packet to be distributed to the receiving terminal To do. The packet distribution unit 17 distributes the distribution packet generated by the packet insertion unit 16 to the receiving terminal.

<Configuration of receiving terminal>
Next, the configuration of the receiving terminal will be described with reference to FIG.
As illustrated in FIG. 3, the receiving terminal includes a packet receiving unit 21, a hash value verification unit 22, a signature verification unit 23, and a verification information reception unit 24.

  The packet receiving unit 21 receives the distribution packet distributed from the packet distribution unit 17 of the digital broadcast content distribution apparatus, and outputs it to the subsequent hash value verification unit 22. The hash value verification unit 22 calculates a hash value of a packet corresponding to an arbitrary number of digital broadcasting contents in the received distribution packet, and calculates the calculated hash value and the hash value stored in the received hash packet. Verify by collating.

  The signature verification unit 23 collates the hash value calculated from the hash packet in the received distribution packet with the hash value stored in the signature packet in the distribution packet, and the disclosure received from the verification information reception unit 24 described later. Use the key to verify the validity of the signature. The verification information receiving unit 24 receives a public key used to confirm the validity of the signature and a public key certificate for verifying the validity of the public key from the digital broadcast content distribution apparatus.

<Hash packet configuration and derivation method>
Next, the configuration and derivation method of the hash packet will be described with reference to FIG.
In the figure, “TS” indicates TS packets, which are arranged in time series according to the transmission order, and a hash packet is arranged in the rear part, that is, in the gap between the TS packets to be transmitted. It has been configured.

  The hash packet derivation method uses a hash function h to collectively calculate a hash value HV1 for any number of 1 to n TS packets (four TS packets in FIG. 4), and this hash value HV1 is stored in the hash packet.

  Next, for the subsequent 1 to n arbitrary number of TS packets (four TS packets in FIG. 4), the previously obtained hash value HV1 and the subsequent 1 to n arbitrary number of TS packets And the hash function HV2 is calculated using the hash function h, and the hash value HV2 is stored in the hash packet.

  Such processing is sequentially performed, and the calculated hash values HV1 to HVn are stored in the hash packets. Further, the hash values HV1 to HVn stored in the hash packet are combined, and the entire hash value PHV is calculated and stored using the hash function h. By performing such processing, a hash packet storing hash values HV1 to HVn and PHV which is the entire hash value is configured. In addition to this, header information storing information on the number of TS packets, the number of hash packets, and multiplicity information is added to the hash packet.

  According to the above method, there is an advantage that the calculation load of the PHV that is the entire hash value can be reduced by hierarchizing the derivation of the hash value. In addition, by using the above-described method, there is an advantage that the buffer on the broadcasting station side, which is a condition for transmitting data in real time, can be zero.

<Relationship between signature packet configuration and hash packet>
Next, the relationship between the structure of the signature packet and the hash packet will be described with reference to FIG.
As shown in FIG. 5, one signature packet 1 is arranged subsequent to a plurality of hash packets (in FIG. 5, hash packet 1 to hash packet 5).

  The PHV that is the entire hash value of each hash packet is arranged in each hash packet with a predetermined redundancy. FIG. 5 shows a case of redundancy 3 and PHV1, which is the entire hash value of hash packet 1, is stored in hash packet 1 to hash packet 3, and PHV2, which is the entire hash value of hash packet 2, is , PHV3 which is stored in hash packet 2 to hash packet 4 and is the entire hash value of hash packet 3 is stored in hash packet 3 to hash packet 5, and PHV4 which is the entire hash value of hash packet 4 is hash The packet 4, the hash packet 5, and the signature packet 1 are stored.

  Note that the PHV5, which is the entire hash value of the hash packet 5, is immediately before the signature packet 1, and is stored only in the hash packet 5 and the signature packet 1. In this case, the PHV5 that is the hash value of the entire hash packet 5 does not satisfy the predetermined redundancy, but in the first place, the purpose of providing the redundancy is to provide resistance against packet loss. On the other hand, if the signature packet is lost, the verification itself is impossible. Therefore, the signature packet is assumed to have no hash loss, and the PHV5, which is the entire hash value of the hash packet 5, is assumed. For the above, the above processing is performed.

  As described above, the signature packet 1 stores PHV4, which is the entire hash value of the hash packet 4, and PHV5, which is the entire hash value of the hash packet 5, in the case of FIG. With respect to PHV1, which is the overall hash value of packet 1, PHV2, which is the overall hash value of hash packet 2, and PHV3, which is the overall hash value of hash packet 3, these are combined and a master packet hash is obtained by hash function h. A value (hereinafter referred to as MPHV) is calculated, and this hash value is stored. Since the free space of the signature packet 1 is limited, PHV1 to PHV3 are stored after being compressed with a hash function.

  PHV4, PHV5, and MPHV stored in the signature packet 1 are combined, and the signature value SIG1 is calculated and stored by the signature function using the secret key generated in the public key / secret key generation unit 11. In addition, by signing the combined PHV4, PHV5, and MPHV, each can be independently verified.

<Processing in digital broadcasting content authentication system>
Next, processing in the digital broadcast content authentication system will be described with reference to FIG.
First, a broadcast station (digital broadcast content distribution apparatus) generates a public key and a secret key for generating a signature in a public key / secret key generation unit (step S101). The broadcast station (digital broadcast content distribution apparatus) transmits the public key generated by the public key / private key generation unit and the public key certificate issued by the certificate authority to the receiving terminal (step S102).

  Next, the broadcast station (digital broadcast content distribution apparatus) uses the hash packet generation unit 14 to generate a hash packet in the manner shown in FIG. 4 (step S103). Further, the signature packet generator 15 generates a signature packet in the manner shown in FIG. 5 (step S104).

  The broadcast station (digital broadcast content distribution device) generates the digital broadcast content distribution packet by inserting the generated hash packet and signature packet into the gap between the TS packets at regular intervals (step S105). Is distributed to the receiving terminal (step S106).

  The receiving terminal receives the distribution packet in the packet reception unit 21, and calculates the hash value of the packet corresponding to an arbitrary number of digital broadcast contents in the received distribution packet in the hash value verification unit 22. Verification is performed by comparing the hash value with the hash value stored in the received hash packet (step S107).

  Further, the hash value calculated from the hash packet is collated with the hash value stored in the signature packet (step S108). Then, the signature verification unit 23 verifies whether the signature for the hash value is valid based on the collation result and the public key received from the broadcasting station (digital broadcast content distribution apparatus) (step S109).

  Therefore, according to the present embodiment, by performing the processing as described above, it is possible to prevent content distribution of unauthorized persons due to impersonation or the like, and to realize a safe broadcasting service.

  In addition, even if the receiving terminal does not have the above function, define a hash packet and a signature packet independently of existing packets, and insert these packets so as not to affect the existing packets. Therefore, it is possible to receive conventional terrestrial digital broadcasting while maintaining compatibility of specifications.

  In addition, in the generation of hash packets, the number of packets for which hash values are calculated can be varied according to the availability of existing packets, so it is possible to generate hash packets while taking into account control within the transmission bandwidth rate. it can. In addition, since a plurality of existing packets are collected and one hash packet is generated, it is possible to prevent an unnecessary increase in data capacity.

  Further, in consideration of the characteristics of broadcast distribution, the hash value of another hash packet is multiplexed with the hash value of one hash packet, and the hash value of one hash packet is included in the hash value of another hash packet. Thus, loss tolerance against packet loss can be increased.

  Each process of the digital broadcast content distribution apparatus and the reception terminal is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read by the digital broadcast content distribution apparatus and the reception terminal and executed. As a result, the digital broadcast content distribution apparatus and digital broadcast content authentication system of the present invention can be realized. The computer system here includes an OS and hardware such as peripheral devices.

  Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW (World Wide Web) system is used. The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.

  The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes a design and the like within a scope not departing from the gist of the present invention. For example, FIG. 4 illustrates an example in which a hash packet is provided after a series of TS packets. However, the present invention is not limited to this, and a configuration in which a hash packet is arranged in front of a series of TS packets may be used. In this case, when the first series of packets has been transmitted to the receiving terminal, it is possible to expect the effect that the falsification detection process can be executed on these series of packets first.

  In FIG. 5, an example in which a signature packet is provided after a series of hash packets has been described. However, the present invention is not limited to this, and a configuration in which a signature packet is arranged in front of a series of hash packets may be used. In this case, in the example of FIG. 5, if the hash packet 1 to the hash packet 3 can be received, the signature can be verified, so that an effect of shortening the processing time can be expected.

  The present invention can realize a safe digital terrestrial broadcasting service. For example, the purpose of use of a one-seg compatible mobile terminal that has been attracting attention in recent years has been expanded, and an added value such as provision of a broadcasting service in a region. We can expect to provide services including

It is a figure which shows the structure of the delivery packet in the conventional terrestrial digital broadcasting, and the structure of the delivery packet in this embodiment. It is a figure which shows the structure of the content delivery apparatus for terrestrial digital broadcasting which concerns on this embodiment. It is a figure which shows the structure of the receiving terminal which concerns on this embodiment. It is a figure which shows the structure and derivation | leading-out method of the hash packet based on this embodiment. It is a figure which shows the relationship between the structure of the signature packet which concerns on this embodiment, and a hash packet. It is a flowchart which shows the process in the content authentication system for digital broadcasting which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Public key / private key generation unit 12 ... Public key certificate reception unit 13 ... Verification information distribution unit 14 ... Hash packet generation unit 15 ... Signature packet generation unit 16 ... Packet Insertion unit 17 ... Packet distribution unit 21 ... Packet reception unit 22 ... Hash value verification unit 23 ... Signature verification unit 24 ... Verification information reception unit

Claims (7)

A digital broadcast content distribution apparatus for distributing digital broadcast content to a receiving terminal,
Key generation means for generating a public key and a private key;
Public key transmitting means for transmitting the public key generated by the key generating means to the receiving terminal;
A hash packet generating means for generating a hash packet for calculating and storing a hash value of a packet corresponding to an arbitrary number of contents for digital broadcasting to be distributed;
Signature packet generation means for generating a signature packet for storing a signature for the hash value of the hash packet;
A distribution packet generation means for generating a distribution packet by inserting the hash packet and the signature packet between packets of the digital broadcast content at an arbitrary interval;
Distribution packet transmitting means for transmitting the generated distribution packet to the receiving terminal;
A content distribution apparatus for digital broadcasting, comprising:   2. The digital broadcast content distribution according to claim 1, wherein the hash packet generation unit varies the number of packets for calculating a hash value according to a distribution interval of packets corresponding to the digital broadcast content. apparatus.   The hash packet generation means divides a packet corresponding to the arbitrary number of digital broadcast contents into an arbitrary number of packet groups, and multiplexes the hash value of the preceding packet group and the hash value of the subsequent packet group. 3. The digital broadcast content according to claim 1, wherein a plurality of hash values are sequentially calculated, and an overall hash value is calculated and stored for the plurality of calculated hash values. Distribution device.   The hash packet generation means stores the entire hash value in each hash packet for a plurality of hash packets according to a predetermined redundancy, and the signature packet generation means adds the predetermined redundancy to the signature packet. The hash value calculated by combining the entire hash value in the hash packet that does not satisfy the above-mentioned value, the hash value calculated by combining the entire hash value in the hash packet that is not directly stored in the signature packet, and the entire hash in the hash packet that does not satisfy the predetermined redundancy A signature value signed by the secret key generated by the key generation means is further combined with the hash value calculated by combining the hash value calculated by combining the entire hash value in the hash packet that is not directly stored in the signature packet. The digital of claim 3 Feed for content distribution apparatus. A digital broadcast content authentication system comprising: a broadcast station including the digital broadcast content distribution device according to claim 1; and a receiving terminal that receives the distributed digital broadcast content.
The receiving terminal is
Public key receiving means for receiving the public key;
A delivery packet receiving means for receiving the delivery packet;
A hash value verification means for calculating a hash value of a packet corresponding to the received arbitrary number of contents for digital broadcasting, and comparing the calculated hash value with a hash value stored in the received hash packet;
A signature verification unit that verifies the validity of the signature using the received public key, while comparing the hash value calculated from the received hash packet with the hash value stored in the signature packet;
A content authentication system for digital broadcasting, comprising: A digital broadcast content authentication method in a digital broadcast content authentication system comprising a broadcast station that distributes digital broadcast content in packets and a receiving terminal that receives the distributed digital broadcast content,
The broadcasting station
A first step of generating a public key and a private key;
A second step of transmitting the generated public key to the receiving terminal;
A third step of generating a hash packet for calculating and storing a hash value of a packet corresponding to an arbitrary number of contents for digital broadcasting to be distributed;
A fourth step of generating a signature packet storing a signature for the hash value of the hash packet;
A fifth step of inserting the hash packet and the signature packet between packets of the digital broadcast content at an arbitrary interval to generate a distribution packet;
A sixth step of transmitting the generated distribution packet to the receiving terminal;
The receiving terminal is
A seventh step of receiving the public key;
An eighth step of receiving the delivery packet;
A ninth step of calculating a hash value of a packet corresponding to the received arbitrary number of digital broadcast contents, and comparing the calculated hash value with a hash value stored in the received hash packet;
A tenth step of collating a hash value calculated from the received hash packet with a hash value stored in the signature packet and verifying the validity of the signature using the received public key;
A content authentication method for digital broadcasting, comprising: A program for causing a computer to perform authentication of digital broadcast content in a digital broadcast content authentication system comprising a broadcasting station that distributes digital broadcast content in packets and a receiving terminal that receives the distributed digital broadcast content. And
The broadcasting station
A first step of generating a public key and a private key;
A second step of transmitting the generated public key to the receiving terminal;
A third step of generating a hash packet for calculating and storing a hash value of a packet corresponding to an arbitrary number of contents for digital broadcasting to be distributed;
A fourth step of generating a signature packet storing a signature for the hash value of the hash packet;
A fifth step of inserting the hash packet and the signature packet between packets of the digital broadcast content at an arbitrary interval to generate a distribution packet;
A sixth step of transmitting the generated distribution packet to the receiving terminal;
The receiving terminal is
A seventh step of receiving the public key;
An eighth step of receiving the delivery packet;
A ninth step of calculating a hash value of a packet corresponding to the received arbitrary number of digital broadcast contents, and comparing the calculated hash value with a hash value stored in the received hash packet;
A tenth step of collating a hash value calculated from the received hash packet with a hash value stored in the signature packet and verifying the validity of the signature using the received public key;
A program that causes a computer to execute.

Images