JP2002027417A - Program storage method and program storage device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a conditional access system and a device for realizing highly secure conditional access in a stored broadcast system in which a broadcasted broadcast is stored, reproduced and viewed when desired. . When a storage encryption process is performed, a plurality of storage encryption keys are generated, and the storage encryption key is changed for each storage packet. High security can be ensured for the selected content.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention utilizes a receiver with an HDD,
The present invention relates to a program storage method for storing content such as a video / audio program or a data broadcast program and charging the content at the time of reproduction, which has high security at the time of storage.

[0002]

2. Description of the Related Art A technique for accumulating a program and accumulating it at the time of reproduction is also described in JP-A-8-125651, "Signal processing device".

In this patent, a distribution encryption key is generated from a first encryption initial value, and a distribution encryption key is decrypted using a distribution encryption key group.
After that, a storage encryption key is generated from the second encryption initial value distributed by radio waves in the same manner as the first encryption initial value, stored and encrypted, and stored in an HDD or the like.

[0004]

However, the above technique has the following problems. 1. There is only one key for content. For this reason, there is a possibility that the security level may be reduced by using one key. In real-time video distribution, since the encryption key is updated once every few seconds, it is necessary to ensure the same level of security. Security is low with only one key. 2. However, if a plurality of keys are used, key management is required, and it is difficult to synchronize with the key switching timing of the content. No consideration is given to the number of keys and encryption timing at the time of distribution and storage. 3. When trying to preview a program, the key is the same in the preview area and the real purchase area, so that fraud is easy depending on the control of the receiver.

[0005]

In order to solve the above-mentioned problem, first, a plurality of storage encryption keys are generated from a key seed, and the storage encryption key corresponding to each storage packet is changed. That is, an encryption processing unit is provided. In addition to the above, by adding a random number element to the generation of the stored key, it is possible to make the key different for each receiver even at the same time.

[0006] Secondly, a storage encryption processing unit is provided in the contents, in which order information such as time information (time stamp) is attached to each packet, and the order information and the generated key are synchronized. That is. Further, by giving a flag for determining the encryption type to the packet of the content, it is possible to explicitly switch the key.

Third, a plurality of storage key seeds are generated and sent,
There is provided an ECM generation unit that prepares two keys, a “preview key” and a “book purchase key”. As a result, the preview part uses the preview key,
The other parts can be encrypted using the purchase key, so that high security can be ensured in the preview system.

[0008]

Embodiments of the present invention will be described below.

The broadcast station creates an ECM (program information) for each program to be charged, and encrypts (scrambles) the video / audio / data content with a scramble key embedded in the ECM.
I do. Thereafter, the transmitting unit multiplexes the scrambled content and the ECM and transmits the multiplexed content.

In the receiver, after receiving, only the ECM is filtered from the received data and passed to the security module. The security module is provided by an IC card, a PCMCIA card, or the like, and may be functionally embedded in the receiver.

In the security module, the acquired E
From the CM, the storage key seed obtaining unit obtains the storage key seed and passes it to the receiver. Upon receiving the storage key seed from the IC card, the receiver generates a plurality of storage keys based on the storage key seed. The storage key is generated from the number information and the like when the content is divided and distributed, and the storage key seed, and is generated so that one storage key can be identified as to which part of the content the storage key corresponds to. The information required to generate the storage key includes time information embedded with the packet, the packet number of the packet, and the like. The content is descrambled in the descrambling unit by the scramble key obtained by the ECM, and then encrypted by the storage encryption unit by the storage encryption unit.
Stored in DD. In addition, at the time of storage, the ECM is also stored in the HDD. Examples of the storage form of the ECM include a case where the ECM is embedded in a content packet as it is delivered, a case where one ECM is cut out and stored, and the like. When accumulating ECM,
In order to enhance security at the time of storage, it is also effective to convert ECM encryption, apply double encryption, or change the ECM format. When the storage memory area in the security module can be secured, the ECM can improve security by storing the ECM in the security module instead of in the receiver.

In the present embodiment, the method of distributing the storage key seed by the ECM and storing the storage key seed in the HDD by storing the ECM is described.
In the case of distributing using a distribution means other than the above, the storage key is generated in the receiver every time the storage is performed, and the storage key
D and the like.

Further, in addition to the above, in addition to the storage key seed and the original information for generating the storage key, a random number or a receiver ID
By adding the same, it becomes possible to make the encrypted byte sequence different when the receiver and the storage timing are different even if the content is the same.

In the method of generating the storage key, the storage time of each packet of the content is given, and the storage key is generated for each packet based on the time. The frequency of key generation becomes very high, which can put a load on the receiver. In order to avoid this, an encryption key type may be set in the header area of the packet, and the generation frequency may be reduced by using the encryption key type. For example, as shown in FIG. 4, if a flag is assigned to the encryption key type and the values of “Even” and “Odd” are set, a storage key is generated based on the time when the flag is switched, and By using a mechanism that uses the stored key until the flag is switched, the storage key generation interval can be provided. Further, by setting the encryption key type to a number instead of a flag, it is possible to indicate the switching more easily.

When a preview period is set for a content, a scramble key for descrambling is provided from the security module during the preview period according to the conventional scrambling method, and the scramble key is provided during a period other than the preview available period. It does not pass the scramble key so that it cannot be decrypted. In this method, the storage key seed corresponding to the preview period for one content and the storage key seed for the part of the content that can be acquired at the time of the actual purchase are separated, so that the preview In the case where the security key is passed from the security module to the receiver and the actual purchase is performed, as shown in FIG. 5, the storage key for preview viewing and the key for purchase are passed on to obtain the encryption. The key and the encryption target can be clearly separated, and the security level can be improved.

Next, the processing for purchasing and playing back the stored program will be described below (see FIG. 3).

When the viewer performs a purchase operation, the receiver passes the ECM stored in the HDD to the security module. The security module performs a charging process based on the received ECM, and passes the storage key seed to the receiver when the charging is completed normally. The receiver generates a plurality of storage keys based on the storage key seed in the same manner as at the time of storage. The storage encryption of the content is decrypted using the generated storage key, and the AV decoder reproduces / executes the content.

[0018]

According to the present invention, it is possible to improve the security level at the time of storage in a system in which contents are stored in the receiver with HDD and charging is performed at the time of reproduction.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of a conventional system.

FIG. 2 is a diagram showing a configuration example of the present invention at the time of accumulation

FIG. 3 is a diagram showing a configuration example of the present invention at the time of reproduction.

FIG. 4 is a diagram illustrating an example of a content storage packet;

FIG. 5 is a diagram showing an example of using a preview key;

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) H04N 5/765 H04L 9/00 601E 5/781 H04N 5/781 510C 7/16 7/167 Z 7/167 (72) Inventor Hironori Murakami 1006 Kadoma, Kazuma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 1006 Odakadoma, Kadoma City, Osaka Prefecture, Matsushita Electric Industrial Co., Ltd. (72) Inventor Toru Nakahara 1006 Odaka, Kadoma City, Osaka Prefecture 2-6-1, Shirakawa Building, Annex Building, 5th Floor Matsushita Electric Information System Nagoya Research Laboratory F-term (reference) 5C025 BA25 BA27 BA30 DA10 5C063 AB05 AC01 AC05 CA23 CA31 DA07 5C064 CA18 CB01 CC01 5J104 AA11 AA16 EA04 EA22 NA02 NA35 PA05

Claims (12)

[Claims] 1. A storage key seed generator for generating a storage key seed, an ECM generator for generating an ECM including the storage key seed, a scrambler for encrypting data, and a transmitter for sending the ECM and data Broadcasting station equipment comprising: a receiving unit that receives data from a broadcasting station; an ECM filtering unit that obtains an ECM from the received data; an ECM interpreting unit that interprets the ECM; and charging based on the received ECM A charging processing unit that performs processing, a storage key seed acquisition unit that obtains a storage key seed from the ECM, a descrambling unit that decodes received scrambled data, a packetization processing unit that packetizes the decrypted data, and a packetization processing unit. A storage encryption unit for storing and encrypting the encrypted data, a storage key generation unit for generating a storage key used for storage encryption from a storage key seed, and an HDD unit for storing the storage encrypted data and the like. To Program accumulation method characterized in that it is constituted by the example was the receiver. 2. The program storage method according to claim 1, wherein a charge processing unit, an ECM interpretation unit, and a storage key seed acquisition unit are provided in the security module. 3. The program storage method according to claim 1, wherein the storage encryption unit that stores and encrypts the data packetized by the packetization processing unit changes a storage key for each packet. 4. A storage key generation unit for generating a plurality of storage keys from storage auxiliary data generated by a storage encryption unit and storage key seeds obtained by a storage seed obtaining unit. Program storage method. 5. A storage key generation unit for generating a plurality of storage keys from storage auxiliary data generated by a storage encryption unit, storage key seeds obtained by a storage seed obtaining unit, and random numbers. The program storage method described. 6. The method according to claim 1, wherein the storage key is transmitted as program information from a transmission unit. 7. The program storage method according to claim 1, wherein the storage key seed is transmitted by PSI / SI from a transmission unit. 8. The program storage method according to claim 1, wherein the storage key seed is generated by a storage encryption key generation unit. 9. The program storage method according to claim 1, further comprising providing an encryption type for each packet to be stored and encrypted, and providing an encryption type assigning unit for specifying which storage encryption key corresponds to the packet. . 10. The method according to claim 9, wherein the encryption type is a flag. 11. The program storage method according to claim 9, wherein the encryption type is a number. 12. The program storage method according to claim 1, wherein a plurality of storage key seeds are generated in a storage key seed generator, and a plurality of storage key seeds are used in a storage encryption processor.