Apparatus and method for processing information as well as recording medium

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to an information processing apparatus and method, and a recording medium, and more particularly to an information processing apparatus and method suitable for use in an apparatus for decrypting encrypted data, and a recording medium.

【0002】

[Conventional technology]

For example, in satellite broadcasting in which a program is distributed via satellite, the data of the program is encrypted and distributed so that a viewer who does not have a contract cannot view the program. When the receiving device of the contracted viewer receives the encrypted data, the encryption is decrypted and the viewer can watch the program, but the viewer who does not have the contract receives the data. Even if the device receives the encrypted data, the data is not decrypted, and as a result, a viewer who does not have a contract cannot watch the program.

【0003】

[Problems to be Solved by the Invention]

The receiving device that receives the above-mentioned encrypted data stores a key for decrypting (authentication) the encryption, and the key is used to decrypt the encryption. .. The information of this key itself is updated at a predetermined cycle so that it will not be used improperly by a contractor who does not have a contract.

【0004】

In addition, encrypted communication is also performed in a digital interface such as IEEE1394. In the case of such encrypted communication, when it is determined that the devices (devices) that communicate with each other execute the authentication process and as a result, the content can be exchanged, the key for decrypting the encryption is shared. This makes it possible to decrypt the content on the receiving side. Even in such encrypted communication, the key is updated at a predetermined cycle.

【0005】

If this update process fails, it may not be possible to decrypt the encrypted data. In addition, it is assumed that decoding may fail due to other causes. If the decryption failed, it could hang because of the failed data. In addition, white noise may occur even if it does not hang up.

【0006】

The present invention has been made in view of such a situation, and an object of the present invention is to prevent the generation of noise by executing mute processing when it is determined that decoding has failed.

【0007】

[Means for solving problems]

The information processing apparatus according to claim 1 has a decoding means for decrypting encrypted data, a determination means for determining whether or not the decoding by the decoding means has failed, and a determination means for decoding by the decoding means. When it is determined that the data is determined to be, it is characterized by including an output stopping means for stopping the output of the data decoded by the decoding means to the subsequent processing.

【0008】

When the output of the data is stopped by the output stop means, the output means for outputting the data indicating that the output is invalid as the data of the subsequent processing can be further included.

【0009】

After the data output is stopped by the output stop means, if the determination means determines that the decoding by the decoding means has not failed, the process of stopping the data output by the output stop means after a predetermined time has elapsed is canceled. Can be done.

【0010】

The information processing method according to claim 4 is a decoding step for decrypting encrypted data, a determination step for determining whether or not the decoding by the processing of the decoding step has failed, and a decoding step for the processing of the determination step. When it is determined that the decoding by the processing has failed, it is characterized by including an output stop step of stopping the output of the data decoded by the processing of the decoding step to the subsequent processing.

【0011】

The program of the recording medium according to claim 5 has a decoding step for decrypting encrypted data, a determination step for determining whether or not the decoding by the processing of the decoding step has failed, and a decoding step in the processing of the determination step. When it is determined that the decoding by the processing of the above is unsuccessful, it is characterized by including an output stop step of stopping the output of the data decoded by the processing of the decoding step to the subsequent processing.

【0012】

In the information processing apparatus according to claim 1, the information processing method according to claim 4, and the recording medium according to claim 5, it is determined whether or not the decryption of the encrypted data has failed, and the data fails. If it is determined that the data has been processed, the output of the decrypted data to the subsequent processing is stopped.

【0013】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of an embodiment of the receiving device 2. In the following description, a case where IEEE1394 is used as an interface for communication will be described as an example. The digital data received by the antenna 1 is input to the tuner 11 of the receiving device 2. The tuner 11 extracts the data of the program instructed by the user and outputs it to the descrambler 12. Normally, digital data distributed by digital broadcasting is scrambled so that it cannot be viewed by non-contracted viewers. When it is determined that viewing is permitted, the descrambler 12 executes a process of descrambling the input digital data.

【0014】

The descrambled digital data is output to terminal a of the IEEE1394 interface 13 and switch 14. The IEEE1394 interface 13 is connected to an IEEE1394 standard bus, and is connected to an HDD video recorder and a digital television receiver (both not shown) via the bus.

【0015】

The digital data output to the terminal a of the switch 14 is output to the demultiplexer 15 when the switch 14 is connected to the terminal a side. The demultiplexer 15 extracts video data, audio data, etc. from the input digital data and outputs the video data to the decoder 16. The decoder 16 generates an analog video signal or audio signal by applying a decoding process according to a predetermined method to the input video data or audio data. The output from the decoder 16 is output to a video tape recorder (not shown) or the like connected by a predetermined cable.

【0016】

The control unit 17 controls each unit in the receiving device 2. Further, the above-mentioned parts are connected to each other by a bus 18.

【0017】

FIG. 2 is a diagram showing an internal configuration of the IEEE1394 interface 13. The data descrambled from the descrambler 12 is input to the encryption / decryption unit 21, encrypted as necessary, and output to other devices connected by the IEEE1394 bus via the input / output unit 22. To. Further, the data input via the IEEE1394 interface 13 is input to the encryption / decryption unit 21 via the input / output unit 22. Here, if the input data is encrypted, it is decrypted by the encryption / decryption unit 21 and output to the terminal b of the switch 14 via the erroneous decryption detection unit 23.

【0018】

The data handled by the receiving device 2 having such a configuration will be described. In the following description, the communication of the IEC60958 standard in the IEEE1394 standard will be described as an example. In addition, audio data will be mainly described. The IEC60958 standard is a method used for optical digital audio communication, and is provided as a digital communication means for audio in digital audio devices such as MD (Mini Disk) and CD (Compact Disc). By this data communication method, digital copying of music from a CD to an MD is performed.

【0019】

The data structure of the IEC60958 standard is shown in Figures 3 and 4. Figure 3 shows the Sub-frame format of audio data. The Sub-frame is one sample of audio data. For example, in the case of music data with a sampling frequency of 44.1 KHz, it corresponds to one sample of left channel or one right channel data. Therefore, in the case of music data with a sampling frequency of 44.1 KHz, 44100 x 2 Sub-frame data are included per second. The Sub-frame consists of a Sync Preamble that indicates the beginning of the data and a data part.

【0020】

The Frame format in FIG. 4 shows that two Sub-frames represent Frame data and 192 Frame data are Block data. The set of Block data becomes audio data. Here, the Sync Preamble at the head of Sub-Frame has B at the head of Channel 1 at the head of Block, M at the head of other Channel 1 (right channel or left channel), and Channel 2 (opposite side of Channel 1). The head of the channel) takes the W code. By detecting this, the head of the Sub-frame and the location of the Block are detected.

【0021】

FIG. 5 shows the format of the IEEE1394 standard isochronous packet. The isochronous packet is composed of a 1394 isochronous packet header, a header CRC, a CIP header, a data field, and a data CRC. Of these, when encrypted data is transmitted, only the data in the data field is encrypted and transmitted. Further, as the data in the data field, a plurality of audio data described with reference to FIGS. 3 and 4 are input.

【0022】

The first two quadreds (2 x 8 bytes) of the isochronous packet are the IEEE1394 isochronous packet headers, the details of which are shown in FIG. This header includes data_length, which indicates the size of data that enters after 2 quads of this header, tag, which indicates whether or not a CIP header is added in the data field (data_field), channel, which indicates the channel on the sending side, and processing code. Tcode (transaction code) indicating, and sy indicating the synchronization code are arranged. Finally, header_CRC, which is an error detection code in the header, is arranged.

【0023】

FIG. 7 is a diagram showing details of the CIP header. In the CIP header, a SID (Source node ID) indicating the node ID of the source and a DBS (Data Block Size in quadlets) indicating the block size of data are arranged. Next to that, FN (Fraction Number) is placed. This represents the number of blocks in which one source packet is divided. The following QPC (Quadlet Padding Count) shows the number of dummy quadreds added. The next SPH (Source Packet Header flag) is a flag indicating whether or not the source packet has a source packet header.

【0024】

The next Res (reserved) is reserved for the future. DBC (Data Block Continuity counter) represents the value of the counter of continuous data blocks for detecting the loss of data blocks. The next line has an FMT (Format ID) indicating the type of data format and an FDF (Format Dependent Field) in which the value corresponding to the format is recorded. The next SYT is a time stamp field, which is used by DVCR (Digital Video Cassette Recorder) to synchronize frames.

【0025】

As described above, the source packet described in FIGS. 3 and 4 is inserted in the data field. The data CRC is an error detection code in the data field.

【0026】

The operation of the receiving device 2 shown in FIG. 1 that handles such packet data will be described with reference to the flowchart of FIG. In step S1, data is input to the input / output unit 22 of the IEEE1394 interface 13. The data input to the input / output unit 22 is further input to the encryption / decryption unit 21. If the input data is encrypted data, the encryption / decryption unit 21 decrypts the data and outputs the data to the erroneous decryption detection unit 23. In step S2, the erroneous decoding detection unit 23 determines whether or not the input data is the data transmitted by the method of the IEC60958 standard. In other words, determining whether or not the data has been transmitted by the method of the IEC60958 standard is to determine whether or not the decrypted data is audio data.

【0027】

The erroneous decoding detection unit 23 can determine whether or not the data has been transmitted by the method of the IEC60958 standard by referring to the data. That is, it is possible to judge from the data written in the FMT field of the CIP header (Fig. 7) in the format of the IEEE1394 isochronous packet shown in FIG. If it is determined in step S2 that the data to be decrypted is the data transmitted by the IEC60958 standard method, the process proceeds to step S3, and the data written in the data field (Fig. 5) is encrypted. Whether it is data or not is determined.

【0028】

The decision made in step S3 is made by referring to the data written in the sy field of the isochronous packet header (FIG. 6). Specifically, if the first 2 bits of the 4-bit data written in the sy field are other than "00", it is determined to be encrypted data. If it is determined in step S3 that the data is encrypted, the process proceeds to step S4, and it is determined whether or not the Sync Preamble has been correctly decrypted.

【0029】

When it is determined that the Sync Preamble has not been correctly decoded, it is conceivable that the decoding of the received data fails or the reception itself fails. In either case, if the audio data that failed to be decoded is sent to the subsequent processing as it is, meaningless data will be processed, and as a result, noise will be caused.

【0030】

Therefore, in step S4, if it is determined that the Sync Preamble was correctly taken, in other words, if it is determined that the audio data was correctly decoded, the process proceeds to step S5, and the subsequent processing, in this case, terminal b It is output. In the process of step S5, there is a case where it is determined in step S3 that the communication is not encrypted communication.

【0031】

On the other hand, if it is determined in step S4 that the Sync Preamble could not be taken correctly, in other words, if it is determined that the audio data could not be correctly decoded, the process proceeds to step S6. In step S6, the mute process is performed. As mentioned above, if data that could not be correctly decoded as audio data is processed as it is, it will cause noise. To prevent such a situation (to prevent noise), mute it. Execute the process (does not make a sound).

【0032】

As the mute process in step S6, the erroneous decoding detection unit 23 may not output data to terminal b, or output silence data (data indicating silence based on the IEC60958 format). You may. In step S2, it may be determined that the processing to step S6 is not the data transmitted by the method of the IEC60958 standard. Since it is determined that the data is not transmitted by the IEC60958 standard method, it means that the data is not audio data, so the mute process is executed. As the mute process, a mute process of another method may be executed in addition to the above-mentioned method.

【0033】

In this way, it is determined whether or not the Sync Preamble specified in the IEC60958 standard is correctly decoded, and only when it is correctly decoded, it is finally output to the speaker (audio output device). This makes it possible to prevent the generation of noise.

【0034】

Here, if it is determined that the received data has failed to be decrypted for some reason, noise can be prevented by executing the mute process, but the mute process is continued as it is. I can't go. For example, if the data is decrypted correctly, it is determined that the decryption was not performed correctly for some reason, and when the mute process is executed, the viewer is told that the mute process is being executed as it is. Not only does it give a false recognition that the receiving device 2 is broken, but it also causes a problem that the service cannot be provided properly.

【0035】

Therefore, when it is determined that the decoding has failed and the mute processing is being executed, it is necessary to cancel the mute processing when it is determined that the decoding was successful again. However, if the mute processing is canceled immediately when it is determined that the decoding is successful, for example, if the decoding fails and the mute processing is entered, the audio is interrupted. It becomes difficult to hear. Therefore, if it is determined that the decoding has failed, the mute process is immediately executed, and then when it is determined that N consecutive data (for example, data of about 0.5 seconds in time) have been successfully decoded. , Try to cancel the mute process. By doing so, it is possible to provide a natural mute process to the viewer.

【0036】

In the above description, the data transmitted by the IEC60958 standard method has been described as an example, but the present invention can also be applied to the data transmitted by the MPEG standard method. For transmission using the IEEE1394 standard of the MPEG standard, the MPEG Transport Paket specified in the ISO / IEC13818-1 Generic Codin of Moving Picture and Associated Audio: System Recomendation H.22 2.0 plan is transmitted by IEEE1394. The IEEE1394 transmission has the same format as the audio data specified in IEC61883-4 described above (Fig. 5), but the data field contains the transport packet shown in Fig. 9 along with the time stamp.

【0037】

The packet header of the transport packet shown in FIG. 9 will be described. sync_byte is a field that indicates an 8-bit sync byte. transport_error_indicator is a 1-bit flag that, for example, if set to 1, indicates that there is at least 1 bit of uncorrectable bit error in the transport stream. payload_unit_start_indicator is a 1-bit flag, and if it is 1, it indicates that the payload of this transport stream packet starts from the first byte of the PES packet, and if it is 0, it is a PES packet in this transport packet. Indicates that has not started.

【0038】

transport_priority is a 1-bit identifier, and when set to 1, it indicates that the packet has a higher priority than other packets with the same PID that do not have this bit set to 1. The PID is a 13-bit field that indicates the type of data stored in the packet payload. transport_scrambling_control is a 2-bit field that indicates the scramble mode of the payload of the transport stream packet.

【0039】

adaptation_field_control is 2-bit field, the bets after transport stream packet header indicates that at least one of the adaptation field and the payload comes. continuity_counter is a 4-bit field that is incremented for each transport stream packet with the same PID.

【0040】

The operation of the IEEE1394 interface 13 with respect to the data transmitted by the MPEG method will be described with reference to the flowchart of FIG. The processing of steps S11 to S16 of the flowchart shown in FIG. 10 is basically the same as the processing of steps S1 to S6 of the flowchart shown in FIG. However, in step S12, it is determined whether or not the transmission is MPEG transmission. The judgment in step S12 is made by referring to the data written in the FMT field of the CIP header of the packet being decrypted.

【0041】

Further, it is determined whether or not the Sync Preamble in step S14 is correctly taken by referring to the value of the Sync byte in the transport packet header shown in FIG. That is, since the value of Sync byte in the transport packet header is set to a fixed value of "0x47", whether or not this value was obtained was determined to determine whether the Sync Preamble in step S14 was correctly taken. It is possible to judge whether or not.

【0042】

The mute process does not output data as in the above case, or outputs a null packet with the value of the PID field set to "0x1FFF". In addition, the mute process is also released as described above when the decoding is performed accurately.

【0043】

In the above-described embodiment, the case where the IEEE1394 bus is used has been described as an example, but the present invention can also be applied to the case where another bus is used. Further, the present invention can be applied not only to digital communication but also to communication such as analog communication, serial communication, and parallel communication. Further, in the above-described embodiment, the audio data has been described, but the present invention can be applied to other data as well.

【0044】

The series of processes described above can be executed by hardware, but can also be executed by software. When a series of processes are executed by software, it is possible to execute various functions by installing a computer in which the programs that make up the software are embedded in dedicated hardware, or by installing various programs. For example, it is installed from a recording medium on a general-purpose personal computer.

【0045】

As shown in FIG. 11, this recording medium is a magnetic disk 121 (including a floppy disk) on which a program is recorded and an optical disk 122 (CD-), which are distributed to provide a program to a user separately from a computer. It is simply composed of packaged media consisting of ROM (Compact Disk-Read Only Memory), DVD (including Digital Versatile Disk), optical magnetic disk 123 (including MD (Mini-Disk)), or semiconductor memory 124. Instead, it is composed of a ROM 102 for storing a program and a hard disk including a storage unit 108, which are provided to the user in a state of being pre-installed in a computer.

【0046】

In the present specification, the steps for describing the program provided by the medium are processed in chronological order according to the order described, and are not necessarily processed in chronological order, but are arranged in parallel or individually. It also includes the processing to be executed.

【0047】

Further, in the present specification, the system represents an entire device composed of a plurality of devices.

【0048】

[Effect of the invention]

As described above, according to the information processing apparatus according to claim 1, the information processing method according to claim 4, and the recording medium according to claim 5, whether or not the decryption of the encrypted data has failed is determined. When the determination is made and it is determined that the data has failed, the output of the decoded data to the subsequent processing is stopped, so that it is possible to prevent noise from being generated due to the data whose decoding has failed.

[Simple explanation of drawings]

[Figure 1]

It is a figure which shows the structure of one Embodiment of the receiving device to which this invention is applied.

[Figure 2]

It is a figure which shows the internal structure of an IEEE1394 interface.

[Fig. 3]

It is a figure which shows the subframe format.

[Fig. 4]

It is a figure which shows the frame format.

[Fig. 5]

It is a figure which shows the format of an isochronous packet.

[Fig. 6]

It is a figure which shows the format of the isochronous packet header.

[Fig. 7]

It is a figure which shows the format of a CIP header.

[Fig. 8]

It is a flowchart explaining the operation of the IEEE1394 interface.

[Fig. 9]

It is a figure which shows the format of the MPEG transport packet.

[Fig. 10]

It is a flowchart explaining the operation of the IEEE1394 interface.

[Fig. 11]

It is a figure explaining the medium.

[Explanation of symbols]

2 Receiver, 11 Tuner, 12 Desk Rambla, 13 IEEE1394 Interface, 14 Switch, 15 Demultiplexer, 16 Decoder, 17 Control, 18 Bus, 21 Decoding, 22 I / O, 23 False Decoding Detect