Chain key broadcast reception system and chain key broadcast receiving method

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a chained key broadcast receiving system and a chained key broadcast receiving method, and more particularly to a scrambled broadcast receiving method in digital broadcasting descrambled using an encryption key.

【0002】

[Conventional technology]

Conventionally, as a key broadcasting system, there is a system that uses a CAS (Conditional Access System) card to receive and decrypt an encryption key for descrambled scrambled broadcasting in digital broadcasting.

【0003】

In the processing of this CAS card, as shown in FIG. 6, the work key decryption module 23 decrypts the encrypted work key broadcast prior to the program by using the master key 24 in the CAS card. Stored in the work key storage unit 21.

【0004】

The scramble key decryption module 22 decrypts the encrypted scramble key broadcast at the same time as the program using the work key stored in the work key storage unit 21 and outputs it to the outside of the card. Although not shown, the scrambled program video is decoded and displayed using the scramble key outside the CAS card.

【0005】

[Problems to be Solved by the Invention]

In the conventional key broadcasting system described above, the same work key is used every time to decrypt the scramble key in one program, so if the work key is obtained in advance, it can be viewed from the middle of the program broadcast. However, even if the viewing is temporarily interrupted in the middle, the scramble key can be generated, so it is not possible to implement a service such that only the viewer who has watched from the beginning to the end of the program can use the key. There is a problem.

【0006】

Further, when the encrypted scramble key is received, the decrypted scramble key is output. Therefore, the reception of the encrypted scramble key and the use of the decrypted scramble key cannot be performed asynchronously. There is a problem.

【0007】

Furthermore, since the storage of the work key and the output of the scramble key are completely separate processes, there is a problem that the decrypted scramble key cannot be used as the work key used for decryption of the scramble key from the next time onward.

【0008】

Therefore, an object of the present invention is to provide a chain key broadcasting system and a chain key broadcasting method capable of solving the above-mentioned problems and realizing a process of using the decrypted key for decryption from the next time onward.

【0009】

[Means for solving problems]

The chained key broadcasting system according to the present invention is a chained key broadcasting receiving system for receiving digital broadcasting, and pre-encrypted contents based on key information obtained when viewing a plurality of programs in the digital broadcasting. It has a means to obtain the key information for decryption.

【0010】

The chained key broadcasting method according to the present invention is a chained key broadcasting receiving method for receiving digital broadcasting, and pre-encrypted content based on key information obtained when viewing a plurality of programs in the digital broadcasting. It includes a step to obtain the key information for decryption.

【0011】

That is, the chain key broadcasting system of the present invention makes it possible to obtain a key for decrypting encrypted contents by viewing a plurality of programs on a device that receives the broadcast.

【0012】

More specifically, the chain key broadcasting system of the present invention uses a chain key receiving means for receiving a chain key, a key identifier thereof, and a target key identifier indicating a chain key to be decrypted by the key, and a target key identifier. A chain that generates a new chain key by decrypting the chain key received by the chain key receiving means using the chain key storage means that retrieves the already stored chain key and the chain key sent from the chain key storage means. It has a key decryption means.

【0013】

By adopting the above configuration, it is possible to realize a mechanism in which the final chain key cannot be decrypted unless all the series of chain keys are received, and the broadcaster can finish the program from the beginning to the end. It is possible to implement a service in which only the viewer who has watched up to or watched the continuous program of the own broadcasting station can obtain the final chain key. For example, it is possible to realize a service in which a person who has watched the program A and the program B can obtain the chain key B, and a person who has watched the program A and the program C can obtain the chain key C.

【0014】

BEST MODE FOR CARRYING OUT THE INVENTION

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a chain key broadcasting system according to an embodiment of the present invention. In FIG. 1, the chain key broadcasting system according to the embodiment of the present invention is composed of a chain key receiving means 1, a chain key decryption means 2, and a chain key storage means 3.

【0015】

The chain key receiving means 1 receives the chain key, the key identifier thereof, and the target key identifier indicating the chain key to be decrypted by the key. The chain key storage means 3 retrieves the chain key already stored by using the target key identifier received by the chain key receiving means 1. The chain key decryption means 2 uses the chain key sent from the chain key storage means 3 to decrypt the chain key received by the chain key receiving means 1 and generates a new chain key.

【0016】

As a result, it is possible to realize a mechanism in which the final chain key cannot be decrypted unless the entire series of chain keys is received, and the broadcaster has watched the program from the beginning to the end or the broadcast station. It is possible to implement a service in which only the viewer who has watched the continuous program without fail can obtain the final chain key.

【0017】

FIG. 2 is a block diagram showing a configuration of a chain key broadcasting system according to an embodiment of the present invention. In FIG. 2, the chain key broadcasting system according to the embodiment of the present invention includes a demax 11, a video decoder 12, a video monitor 13, a chain key handler 14, a chain key decryption module 15, and a chain key management module 16. It is composed of a content decryption module 17, a chain key memory 18, and a hard disk 19.

【0018】

Demax 11 receives a digital broadcast signal and separates the digital broadcast signal into MPEG (Moving Picture Experts Group) data such as video and audio, an encryption chain key, a key identifier, and a target key identifier.

【0019】

The video decoder 12 decodes the MPEG data and generates the video data. The video monitor 13 displays and reproduces the video data generated by the video decoder 12 on a monitor (not shown).

【0020】

When the chain key management module 16 receives the key identifier and the encrypted chain key from the chain key handler 14, it records the encrypted chain key as a chain key in the chain key memory 18 as a pair with the identifier, and targets it from the chain key handler 14. When the key identifier is received, the chain key paired with the target key identifier in the chain key memory 18 is sent to the chain key decryption module 15.

【0021】

Further, when the chain key management module 16 receives the key identifier and the chain key from the chain key decryption module 15, it records them in the chain key memory as a pair, and when it receives the key identifier from the content decryption module 17, it is chained. The chain key paired with the key identifier in the key memory 18 is returned to the content decryption module 17.

【0022】

The chain key handler 14 receives the encrypted chain key, the key identifier, and the target key identifier from Demax 11. When the target key identifier is null, the chain key handler 14 considers that the encrypted chain key is the first chain key in a series and sends it to the chain key management module 16 together with the key identifier. If the target key identifier is not null, the chain key handler 14 sends the target key identifier to the chain key management module 16 assuming that it is the second and subsequent encrypted chain keys, and sends the encrypted chain key and the key identifier to each other. Send to the chain key decryption module 15.

【0023】

The chain key decryption module 15 decrypts the encrypted chain key using the chain key received from the chain key management module 16, obtains a new chain key, and sends it to the chain key management module 16 together with the key identifier.

【0024】

The content decryption module 17 sends a key identifier to the chain key management module 16 and decrypts the encrypted content in the hard disk 19 using the chain key obtained from the chain key management module 16 to obtain the target content (decrypted content). To get. The hard disk 19 stores encrypted contents obtained in advance via broadcasting, communication, distribution media, or the like.

【0025】

FIG. 3 is a diagram showing the configuration of the chain key memory 18 of FIG. In FIG. 3, the chained key memory 18 stores the key identifier #n (n = 1,2,3,4,5, ...) and the chained key #n paired with the key identifier #n. ..

【0026】

FIG. 4 is a flowchart showing a chain key generation process of a chain key broadcasting system according to an embodiment of the present invention. The chain key generation process of the chain key broadcasting system according to the embodiment of the present invention will be described with reference to FIGS. 2 to 4. In the chain key broadcasting system according to the embodiment of the present invention, the chain key is sequentially generated by the chain key handler 14, the chain key management module 16, and the chain key decryption module 16.

【0027】

When the encrypted chain key, its key identifier, and the target key identifier are given to the chain key handler 14 (step S1 in FIG. 4), the chain key handler 14 determines the target key identifier, and if the target key identifier is null (). In FIG. 4 step S2), the key identifier and the encrypted chain key are sent to the chain key management module 16, and the chain key management module 16 pairs them and stores them in the chain key memory 18 (FIG. 4 step S7).

【0028】

If the target key identifier is not null (step S2 in Figure 4), the chained key handler 14 obtains new chained keys from the encrypted chained key, and the chained key management module 16 stores them in the chained key memory 18. Store (Fig. 4, step S6).

【0029】

In the procedure for obtaining a new chain key from the encrypted chain key, the chain key handler 14 first sends the target key identifier to the chain key management module 16, and the chain key management module 16 sends the paired chain key to the chain key decryption module 15. (Fig. 4, step S3). At the same time, the chain key handler 14 sends the key identifier and the encrypted chain key to the chain key decryption module 15 (Fig. 4, step S4).

【0030】

The chain key decryption module 15 decrypts the encrypted chain key obtained by the chain key handler 14 with the chain key obtained from the chain key management module 16 to obtain a new chain key (Fig. 4, step S5). The chain key decryption module 15 sends a new chain key and a key identifier obtained from the chain key management module 16 to the chain key management module 16, and the chain key management module 16 pairs these and stores them in the chain key memory 18. (Fig. 4, step S6).

【0031】

FIG. 5 is a flowchart showing a decryption process of the encrypted content of the chain key broadcasting system according to the embodiment of the present invention. The decryption process of the encrypted content of the chain key broadcasting system according to the embodiment of the present invention will be described with reference to FIGS. 2, 3 and 5. In the chain key broadcasting system according to the embodiment of the present invention, the content decryption module 17 and the chain key management module 16 decrypt the encrypted content by using the chain key.

【0032】

In this case, the content decryption module 17 specifies the key identifier and retrieves the chain key from the chain key management module 16 (FIG. 5, step S11). The content decryption module 17 decrypts the encryption content using the chain key obtained from the chain key management module 16 (step S12 in FIG. 5).

【0033】

In this way, by sequentially decoding the key received next with the key received last time, the program was watched from the beginning to the end, or the serial drama was watched all the time, and the entire series of keys was received. Only the viewer can get the final key. For example, it is possible to realize a broadcasting service in which desired contents can be decrypted and obtained.

【0034】

In addition, by independently performing a series of processes of receiving, decrypting, and storing the chain key and a process using the chain key, for example, a process of decrypting encrypted contents, the chain key is received, decrypted, and stored. Even when the content is not stored (for example, when the program is not being viewed), the encrypted content stored in the storage medium or the like can be decrypted using the key.

【0035】

Further, by designating an arbitrary chain key identifier as the target identifier, it is not always necessary to broadcast the chain keys in order. For example, the target key of the chain key B that broadcasts the chain key A in the program A and sends it in the program B. By setting the identifier as the chain key A and the target key identifier of the chain key C sent by the program C as the chain key A, the person who viewed the program A and the program B can use the chain key B and the program A and the program C. The viewer can flexibly implement a service such as obtaining the chain key C. Therefore, it is possible to realize a process of using the decrypted key for decryption from the next time onward.

【0036】

[Effect of the invention]

As described above, according to the present invention, in the chain key broadcast receiving system for receiving digital broadcasts, pre-encrypted contents are decrypted based on the key information obtained when a plurality of programs in digital broadcasts are viewed. By obtaining the key information for decryption, there is an effect that the process of using the decrypted key for decryption from the next time onward can be realized.

[Simple explanation of drawings]

[Figure 1]

It is a block diagram which shows the structure of the chain key broadcasting system by embodiment of this invention.

[Figure 2]

It is a block diagram which shows the structure of the chain key broadcasting system by one Example of this invention.

[Fig. 3]

It is a figure which shows the structure of the chained key memory of FIG.

[Fig. 4]

It is a flowchart which shows the chain key generation processing of the chain key broadcasting system by one Example of this invention.

[Fig. 5]

It is a flowchart which shows the decryption process of the encrypted content of the chain key broadcasting system by one Embodiment of this invention.

[Fig. 6]

It is a block diagram which shows the structure of the key broadcasting system by a conventional example.

[Explanation of symbols]

1 Chain key receiving means 2 Chain key decryption means 3 Chain key storage method 11 Demax 12 Video decoder 13 Video monitor 14 Chained key handler 15 Chained key decryption module 16 Chained key management module 17 Content Decryption Module 18 Chained key memory 19 hard disk