JP2003157003A - Digital signal recording and reproducing device, recorder and reproducing device therefor, and digital signal recording and reproducing method, recording method and reproducing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method for recording block-ciphered data on a recording medium so as to enable special reproduction and reproducing the data. SOLUTION: The device is provided with a ciphering part 11 for block- ciphering a payload of a TS packet, a cipher block head flag addition part 12 for adding information indicating whether or not a payload head is a head of a cipher block, a data recording part 13 for recording the TS packet to which cipher block head information is added in the recording medium, a data read part 15 for reading the TS packet from the recording medium, a cipher block head flag analysis part 16 for analyzing whether or not the payload head of the read TS packet is the head of the cipher block on the basis of the cipher block head information and starting output from the TS packet whose payload head is the head of the cipher block, and a deciphering part 17 for deciphering the TS packet outputted from the cipher block head flag analysis part 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for block-encoding digitally encoded data and recording or reproducing the data.

[0002]

2. Description of the Related Art For example, in Japanese Patent Laid-Open No. 2000-331421, there is MPEG2 (Moving Picture Experts Group).
Phase2) A technique of determining each frame structure of image data, recording an identifier for identifying each frame structure by incorporating it in a transport packet (TS packet), and
A technique for selecting and decoding only TS packets having a frame structure necessary for special reproduction when performing special reproduction of recorded data is disclosed.

From the viewpoint of copyright protection of digital contents, it is required to encrypt and record the contents. In order to encrypt a large amount of data such as a transport stream, a block cipher method that divides the data (plaintext) into blocks of a certain length and performs encryption and decryption in block units is suitable. .

[0004]

By the way, in the block cipher system, correct decryption cannot be performed unless the decryption is started from the head of the cipher block. However, when performing reproduction (including special reproduction) in the conventional recording / reproducing apparatus, random access is made on the recording medium, and therefore the beginning of the payload of the accessed TS packet is the beginning of the cipher block. However, the block-encrypted data could not be reproduced.

Therefore, the present invention has been made in order to solve the above-mentioned problems of the prior art, and its object is to enable reproduction of block-encrypted data on a recording medium. Digital signal recording apparatus and recording method, digital signal reproducing apparatus and reproducing method capable of reproducing block encrypted data recorded on a recording medium, and reproducing block encrypted data on a recording medium It is an object of the present invention to provide a digital signal recording / reproducing apparatus and a recording / reproducing method capable of recording and reproducing this data so as to enable recording.

[0006]

According to a first aspect of the present invention, there is provided a digital signal recording / reproducing apparatus which comprises an encryption means for encrypting a payload of a received transport packet by a block encryption method, and the beginning of the payload is an encrypted block. Cipher block head information adding means for adding cipher block head information indicating whether or not it is the head to the transport packet, and recording means for recording the transport packet with the cipher block head information added to a recording medium,
Read-out means for reading out the transport packet from the recording medium, and whether or not the head of the payload of the transport packet read out by the read-out means is the head of the cipher block is analyzed based on cipher block head information, and the payload is read. Is provided with cipher block head information analysis means for starting output from a transport packet whose head is the head of the cipher block, and decoding means for decoding the transport packet output from the cipher block head information analysis means. I am trying.

According to a second aspect of the present invention, in the digital signal recording / reproducing apparatus, the cipher block head information is added by the cipher block head information adding means, and the cipher block head information is inserted as a private data byte in the adaptation field of the transport packet. It is characterized by doing by doing.

According to a third aspect of the present invention, in the digital signal recording / reproducing apparatus, the cipher block head information is added by the cipher block head information adding means in the area immediately before the transport packet header for each transport packet. The feature is that it is performed by adding information.

According to a fourth aspect of the present invention, there is provided a digital signal recording / reproducing apparatus which comprises a data adding means for adding dummy data so that the payload length of a received transport packet becomes equal to an integral multiple of the block length at the time of block encryption. An encryption means for encrypting the payload of the transport packet to which the dummy data is added by the data addition means by a block encryption method, and a transport packet having the payload encrypted by the encryption means is recorded on a recording medium. A recording unit, a reading unit for reading a transport packet from the recording medium, a decoding unit for decoding the payload of the transport packet read by the reading unit, and a payload added by the decoding unit. Data deletion to delete dummy data It is characterized by having a means.

According to a fifth aspect of the digital signal recording apparatus,
An encryption means for encrypting the payload of the received transport packet by a block cipher method, and a cipher for adding cipher block head information indicating whether or not the head of the payload is the head of the cipher block to the transport packet. It is characterized by comprising block head information adding means and recording means for recording a transport packet to which the above-mentioned block head information is added on a recording medium.

According to a sixth aspect of the present invention, in addition to the cipher block head information added by the cipher block head information adding means, the cipher block head information is inserted as a private data byte in the adaptation field of the transport packet. It is characterized by doing by doing.

According to a seventh aspect of the present invention, in the digital signal recording apparatus, the cipher block head information is added by the cipher block head information adding means in the area immediately before the transport packet header for each transport packet. It is characterized by performing by adding.

According to an eighth aspect of the digital signal recording apparatus,
Data adding means for adding dummy data so that the payload length of the received transport packet becomes equal to an integral multiple of the block length at the time of block encryption, and the payload to which the dummy data is added by the data adding means is block encrypted. It is characterized in that it has an encryption means for encrypting by a method and a recording means for recording a transport packet having a payload encrypted by the encryption means on a recording medium.

A digital signal reproducing apparatus according to a ninth aspect is
From the recording medium on which the transport packet in which the payload is encrypted by the block encryption method and the cipher block head information indicating whether the head of the payload is the head of the cipher block is added is recorded, Based on the cipher block head information, the read means for reading the port packet and whether the head of the payload of the transport packet read by the read means is the head of the cipher block is analyzed based on cipher block head information, and the head of the payload is the cipher block. It is characterized by comprising cipher block head information analysis means for starting output from the transport packet which is the head of, and decoding means for decoding the transport packet output from the cipher block head information analysis means.

In the digital signal reproducing apparatus according to the tenth aspect, the dummy data is added so that the payload length becomes equal to an integral multiple of the block length in the block encryption, and then the payload is encrypted by the block encryption method. Reading means for reading the transport packet from a recording medium on which the transport packet is recorded, decoding means for decoding the payload of the transport packet read by the reading means, and payload decoded by the decoding means And a data deleting unit that deletes the dummy data added to the.

In the digital signal recording / reproducing method according to the eleventh aspect, the payload of the received transport packet is encrypted by the block encryption method, and the cipher block head indicating whether the head of the payload is the head of the cipher block or not. Add information to the transport packet,
The transport packet to which the cipher block head information is added is recorded on a recording medium, the transport packet is read from the recording medium, and the head of the payload of the transport packet read from the recording medium is the head of the cipher block. It is characterized in that it is analyzed whether or not there is the cipher block head information, and the decoding is started from the transport packet in which the head of the payload is the head of the cipher block.

The digital signal recording / reproducing method according to the twelfth aspect is characterized in that the cipher block head information is added by inserting the cipher block head information as a private data byte into an adaptation field of a transport packet. I am trying.

In the digital signal recording / reproducing method according to the thirteenth aspect, the cipher block head information is added by adding the cipher block head information to the area immediately before the transport packet header for each transport packet. It is characterized by that.

In the digital signal recording / reproducing method according to the fourteenth aspect, dummy data is added so that the payload length of the received transport packet becomes equal to an integral multiple of the block length at the time of block encryption, and the dummy data is added. The payload of the added transport packet is encrypted by a block encryption method, and the transport packet having the encrypted payload is recorded on a recording medium,
Reading a transport packet from the recording medium,
The payload of the transport packet read from the recording medium is decoded, and the dummy data added to the decoded payload is deleted.

According to a fifteenth aspect of the present invention, in the digital signal recording method, the payload of the received transport packet is encrypted by a block encryption method, and the cipher block head information indicating whether the head of the payload is the head of the cipher block or not. Is added to the transport packet, and the transport packet to which the cipher block head information is added is recorded on a recording medium.

The digital signal recording method according to the sixteenth aspect is characterized in that the cipher block head information is added by inserting the cipher block head information as a private data byte into an adaptation field of a transport packet. I am trying.

Further, in the digital signal recording method according to the seventeenth aspect, the cipher block head information is added by adding the cipher block head information to the area immediately before the transport packet header for each transport packet. It is characterized by that.

In the digital signal recording method according to claim 18, dummy data is added so that the payload length of the received transport packet becomes equal to an integral multiple of the block length at the time of block encryption, and the dummy data is added. The payload of the encrypted transport packet is encrypted by a block encryption method, and the transport packet having the encrypted payload is recorded in a recording medium.

In the digital signal reproducing method according to claim 19, the payload is encrypted by a block cipher system,
Moreover, the transport packet is read from the recording medium in which the transport packet to which the cipher block head information indicating whether the head of the payload is the head of the cipher block is added is recorded and read out. Characterized by analyzing whether or not the head of the payload of the transport packet is the head of the cipher block based on the cipher block head information, and starting decoding from the transport packet in which the head of the payload is the head of the cipher block There is.

In the digital signal reproducing method according to the twentieth aspect, dummy data is added so that the payload length is equal to an integral multiple of the block length at the time of block encryption, and then the payload is encrypted by the block encryption method. The transport packet is read from a recording medium on which the transport packet is recorded, the payload of the read transport packet is decoded, and the dummy data added to the decoded payload is deleted. I am trying.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION First, an MPEG2 transport stream (TS) which is a digital coded signal received by a digital signal recording / reproducing apparatus according to Embodiments 1 to 4 of the present invention will be described. FIG. 2 is a schematic diagram of transport packets (TS packets) that form a TS. One TS packet has a fixed-length packet size of 188 bytes, and a packet header (hereinafter referred to as “header”) is assigned a size of 4 bytes. As shown in FIG. 2, 184 bytes excluding the header of the TS packet is composed of an adaptation field and / or a payload (data part).
When the adaptation field and the payload coexist, the adaptation field always exists before the payload. That is, the structure of the TS packet is
There are three types: "header + payload" structure, "header + adaptation field" structure, and "header + adaptation field + payload" structure. The payload is composed of PES packets of main data such as audio and images.

The size of the adaptation field can be expanded by the private data byte field. Transport Private Data Flag (tr) in the adaptation field
support_private_data_fla
If g) is '1', it indicates that there are private data bytes, in this case the transport private data length (transport_pri).
The number of private data bytes is indicated by the "vate_data_length" field.

Next, a common key block encryption method used for encryption of a large amount of data such as streams will be described. In the common key cryptosystem, the same secret key is used for both encryption and decryption. In the common key block cipher system, plain text is divided into blocks of a fixed block length, encryption processing is performed using a common key, and decryption is also performed using the common key in the same block unit.

Embodiment 1 FIG. 1 is a block diagram showing a digital signal recording / reproducing apparatus according to Embodiment 1 of the present invention (an apparatus for carrying out a digital signal recording / reproducing method according to Embodiment 1).

As shown in FIG. 1, the digital signal recording / reproducing apparatus according to the first embodiment has an encryption unit 11 for encrypting the payload of a received TS packet by a block encryption method, and the beginning of the payload is encrypted. A cipher block head flag addition unit 12 for adding a cipher block head flag indicating whether or not it is the head of the block to the TS packet,
The data recording unit 13 records the TS packet to which the cipher block head flag is added in the recording medium 14. Further, the digital signal recording / reproducing apparatus according to the first embodiment is
A data reading unit 15 that reads a TS packet from the recording medium 14, and whether the head of the payload of the TS packet read by the data reading unit 15 is the head of the cipher block is analyzed based on the cipher block head flag. It has a cipher block head flag analysis unit 16 that starts output from a TS packet whose head of the payload is the head of the cipher block, and a decoding unit 17 that decodes the TS packet output from the cipher block head flag analysis unit 16. .

The recording medium 14 is a storage device (for example, a hard disk device) provided as a part of the digital signal recording / reproducing apparatus, and a recording medium that can be inserted into and removed from the digital signal recording / reproducing apparatus (for example, a recording medium). Optical disk or magnetic disk).

First, the recording of the cipher block on the recording medium 14 will be described. The TS received by a digital broadcast tuner or the like (not shown) is first sent to the encryption unit 11. The encryption unit 11 performs N-byte (N is a predetermined positive integer) block-unit encryption from the beginning of the payload of the TS packet by the common key block encryption method.
Since the cipher block length and the payload length are not always in an integral multiple relationship, when the payload part of the TS packet is block-encrypted, the head of the payload of the TS packet does not necessarily become the head of the cipher block.

The cipher block head flag adding unit 12 inserts a cipher block head flag indicating whether or not the head of the cipher block is the head of the payload of the TS packet into the TS packet. The TS packet to which the cipher block head flag is added by the cipher block head flag adding unit 12 is
It is sent to the data recording unit 13. The data recording unit records the TS packet to which the cipher block head flag is added on the recording medium 14.

Next, the reproduction of the data recorded on the recording medium 14 will be described. The data recorded on the recording medium 14 is read by the data reading unit 15 in TS packet units. The read TS packet is
It is sent to the cipher block head flag analysis unit 16. Here, after the reproduction start instruction including random access, if the packet in which the cipher block head matches the payload of the TS packet is not detected, first, the cipher block head flag is analyzed. As a result, if the beginning of the payload of the TS packet is the beginning of the cipher block,
The data is transferred to the decoding unit 17, and decoding is started from the TS packet. If the payload head is not the head of the cipher block, the TS packet is deleted. For some time after the playback start instruction is received, the payload head of the TS packet is likely not to be the cipher block head, and the TS packet is deleted until the TS packet whose payload head is the cipher block head is detected. Will be. Once a packet in which the cipher block head matches the TS packet payload is detected, the cipher block head flag is not analyzed, and the data is passed to the decryption unit 17 to be decrypted.

Each time a random access occurs, the decryption start point is searched by analyzing the cipher block head flag as described above. The decrypted TS packet is
The cipher block head flag is removed, and the result is output to a demultiplexer (not shown) in the subsequent stage, and reproduced by the reproducing unit into video or audio.

As described above, in the digital signal recording / reproducing apparatus according to the first embodiment, the cipher block head flag is added to each TS packet before the recording medium 14 is added.
Since the TS packet is recorded in, the TS packet whose payload head is the head of the cipher block can be easily detected at the time of normal access or random access such as special playback.
As a result, the decoding can be surely started.

From the configuration for data recording (encryption unit 11, cipher block head flag addition unit 12, and data recording unit 13) in the configuration of the digital signal recording and reproducing apparatus according to the first embodiment, The signal recording device (the device that implements the digital signal recording method according to the first embodiment) can also be configured as an independent device. In addition, from the configuration for data reproduction (data read unit 15, cipher block head flag analysis unit 16, and decryption unit 17) in the configuration of the digital signal recording / reproduction device according to the first embodiment, the digital recording / reproduction device The (device for implementing the digital signal reproducing method according to the first embodiment) may be configured as an independent device.

Embodiment 2 FIG. 3 is a diagram showing an encryption block head flag insertion position in a digital signal recording / reproducing apparatus according to Embodiment 2 of the present invention. In the digital signal recording / reproducing apparatus according to the second embodiment, as shown in FIG. 3, the block head flag insertion position is inserted in the private data byte of the adaptation field of the TS packet. Further, the cipher block head flag to be inserted into the private data byte may be inserted only when the head of the cipher block is the head of the TS packet payload.

At the start of reproduction, the TS packet read from the data reading section 15 is sent to the cipher block head flag analysis section 16. Here, the cipher block head flag inserted in the private data byte of the adaptation field is set to the cipher block head flag. When the result of the analysis indicates that the beginning of the payload of the TS packet matches the beginning of the cipher block, the TS packet is first decrypted by the decoding unit 1.
7 and starts decoding. The video signal obtained by this decoding process is displayed as a moving image on the display.

Since the digital signal recording / reproducing apparatus according to the second embodiment inserts the cipher block head flag into the private data bytes of the adaptation field as described above, it can record in a format conforming to the MPEG standard. At the time of starting the normal reproduction or at the time of random access such as special reproduction, the TS packet whose payload is the head of the cipher block can be easily detected, so that the decoding can be surely started.

The second embodiment is the same as the first embodiment except for the points described above.

Third Embodiment FIG. 4 is a diagram showing a cipher block head flag insertion position in a digital signal recording / reproducing apparatus according to a third embodiment of the present invention. In the digital signal recording / reproducing apparatus according to the third embodiment, as shown in FIG. 4, the addition position of the cipher block head flag of the cipher block head flag adding unit 12 is added before the header of the TS packet. ing.

At the start of reproduction, the TS packet read from the data reading unit 15 is sent to the cipher block head flag analysis unit 16. Here, the cipher block head flag added immediately before the header of the TS packet is analyzed. Then, as a result, when it is indicated that the payload head of the TS packet matches the head of the cipher block, the TS packet is first transferred to the decryption unit 17, and the decryption is started. The cipher block head flag is removed from the TS packet transferred to the decryption unit 17.

As described above, the digital signal recording / reproducing apparatus according to the third embodiment adds the cipher block head flag immediately before the TS packet header and records it. Therefore, the decoding start position can be detected by a simple circuit.

The third embodiment is the same as the first embodiment except for the points described above.

Fourth Embodiment FIG. 5 is a block diagram showing a digital signal recording / reproducing apparatus according to a fourth embodiment of the present invention (an apparatus for carrying out the digital signal recording / reproducing method according to the fourth embodiment).

As shown in FIG. 5, the digital signal recording / reproducing apparatus according to the fourth embodiment uses dummy data so that the payload length of the received TS packet is equal to an integral multiple of the block length at the time of block encryption. (For example, it may be any data as long as it is random number data and can be distinguished from the payload.)
An encryption unit 52 that encrypts the payload to which the dummy data is added by the dummy data addition unit 51 by the block encryption method, and a TS packet having the payload encrypted by the encryption unit 52 is recorded in the recording medium 54. And a data recording unit 53. Further, the digital signal recording / reproducing apparatus according to the fourth embodiment includes a data reading unit 55 that reads a TS packet from the recording medium 54, and a decoding unit 56 that decodes the payload of the TS packet read by the data reading unit 55. , And a dummy data removing unit 57 that deletes dummy data added to the payload decrypted by the decrypting unit 56.

The recording medium 54 is a storage device (for example, a hard disk device) provided as a part of the digital signal recording / reproducing apparatus, and a recording medium that can be inserted into and removed from the digital signal recording / reproducing apparatus (eg, a recording medium). Optical disk or magnetic disk).

Further, in the configuration of the digital signal recording / reproducing apparatus according to the fourth embodiment, the configuration for data recording (dummy data adding section 51, encryption section 52, and data recording section 53) is used for digital signal recording. An apparatus (an apparatus that implements the digital signal recording method according to the fourth embodiment) can also be configured. Further, in the configuration for data reproduction (data reading unit 55, decoding unit 56, and dummy data removing unit 57) in the configuration of the digital signal recording / reproducing device according to the fourth embodiment, the digital recording / reproducing device (implementation Form 4
Device for implementing the digital signal reproducing method according to the present invention.

In the first, second, and third embodiments, the encryption unit 11 is used.
At the same time as the encryption process, the cipher block head flag addition unit 12 adds a cipher flag indicating the head of the cipher block, and the cipher block head flag analysis unit 16 always refers to this flag at the start of random access to ensure that the cipher block head is I was able to start decryption from. In the fourth embodiment, adjustment is performed so that the payload heads of all TS packets are always the heads of cipher blocks.

The TS packet received by the tuner for digital broadcasting is first sent to the dummy data adding section 51. Since the payload length of the TS packet and the cipher block length are not necessarily in an integral multiple relationship, the last part of the payload of the TS packet may be less than the cipher block length. The dummy data adding unit 51 adds dummy data of random number data to the payload so that it becomes equal to an integral multiple of the cipher block length. Next, it is sent to the encryption unit 52, and encryption is performed from the beginning of the payload of the TS packet. The TS packet to which the cipher block head flag is added by the encryption unit 52 is sent to the data recording unit 53 and recorded on the recording medium 54.

Next, the reproduction of the data recorded on the recording medium 54 will be described. The data recorded on the recording medium 54 is read by the data reading unit 55 in TS packet units.

Since the beginning of the payload of the read TS packet is always located at the beginning of the cipher block, as long as decoding is performed in units of TS packets with dummy data added, the decryption unit 56 remains TS. Can decrypt packets. After decryption, the dummy data deletion unit 57
The dummy data added to the TS packet is deleted, the TS packet is output to a demultiplexer (not shown) in the subsequent stage, and video or audio is reproduced.

Since the digital signal recording / reproducing apparatus according to the fourth embodiment is adjusted so that the head of the payload of the TS packet is always the cipher block head by adding the dummy data as described above, the normal reproduction is performed. It is possible to surely decrypt even at the time of starting or random access such as special reproduction.

[0055]

As described above, according to the digital signal recording / reproducing apparatus of the first to third aspects, the cipher block head information is added to each TS packet before the T is recorded on the recording medium.
Since the S packet is recorded and the decoding is started from the TS packet whose payload is the head of the cipher block when the reproduction is started, the reproduction can be surely performed even when the normal reproduction is started or the random access including the special reproduction is performed.

According to the digital signal recording / reproducing apparatus of the fourth aspect, since the head of the payload of the TS packet is always adjusted to be the head of the cipher block, even at the start of normal reproduction or at the time of random access including special reproduction. Reproduction can be reliably performed.

Further, according to the digital signal recording apparatus of the fifth to seventh aspects, since the cipher block head information is added to each TS packet and then the TS packet is recorded on the recording medium, the payload has the cipher block at the start of reproduction. It is possible to start decoding from the TS packet at the beginning of, and it is possible to reliably perform reproduction even at the start of normal reproduction or at random access including special reproduction.

Further, according to the digital signal recording apparatus of the eighth aspect, since the head of the payload of the TS packet is adjusted to always be the head of the cipher block, at the time of starting the normal reproduction or at the time of random access including special reproduction. However, it can be surely reproduced.

In addition, according to the digital signal reproducing apparatus of the ninth aspect, since the decoding is started from the TS packet whose payload is the head of the cipher block at the time of starting the reproduction, at the time of starting the normal reproduction or at the time of random access including special reproduction. However, it can be surely reproduced.

Further, according to the digital signal reproducing apparatus of the tenth aspect, since the head of the payload of the TS packet is adjusted to be always the head of the cipher block, at the time of starting the normal reproduction or at the time of random access including special reproduction. However, it can be surely reproduced.

According to the digital signal recording / reproducing method of the eleventh to thirteenth aspects, the cipher block head information is added to each TS packet and then the TS packet is recorded on the recording medium, and when the reproduction is started, the payload has the cipher block. Since the decoding is started from the TS packet at the beginning of the, it is possible to surely perform the reproduction even at the start of the normal reproduction or at the time of random access including special reproduction.

According to the digital signal recording / reproducing method of the fourteenth aspect, since the head of the payload of the TS packet is always adjusted to be the head of the cipher block, at the start of normal reproduction or random access including special reproduction. Reproduction can be reliably performed even at times.

According to the digital signal recording method of the fifteenth to seventeenth aspects, since the cipher block head information is added to each TS packet before the TS packet is recorded on the recording medium, the payload has the cipher block at the start of reproduction. It is possible to start decoding from the TS packet at the beginning of, and it is possible to reliably perform reproduction even at the start of normal reproduction or at random access including special reproduction.

Further, according to the digital signal recording method of the eighteenth aspect, since the head of the payload of the TS packet is adjusted to always be the head of the cipher block, at the start of normal reproduction or at the time of random access including special reproduction. However, it can be surely reproduced.

Further, according to the digital signal reproducing method of claim 19, since the decoding is started from the TS packet whose payload is the head of the cipher block at the start of reproduction, at the time of starting normal reproduction or at random access including special reproduction. However, it can be surely reproduced.

Further, according to the digital signal reproducing method of the twentieth aspect, since the head of the payload of the TS packet is always adjusted to be the head of the cipher block, at the start of normal reproduction or at the time of random access including special reproduction. However, it can be surely reproduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a digital signal recording / reproducing apparatus according to a first embodiment of the present invention.

[Fig. 2] Fig. 2 is a configuration diagram of TS packets constituting a transport stream in MPEG2.

FIG. 3 is a diagram showing a cipher block head flag insertion position in a digital signal recording / reproducing apparatus according to a second embodiment of the present invention.

FIG. 4 is a diagram showing cipher block head flag addition positions in a digital signal recording / reproducing apparatus according to a third embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a digital signal recording / reproducing device according to a fourth embodiment of the present invention.

[Explanation of symbols]

11 encryption unit, 12 cipher block head flag addition unit, 13 data recording unit, 14 recording medium, 15
Data read unit, 16 cipher block head flag analysis unit, 17 decryption unit, 51 dummy data addition unit, 52 encryption unit, 53 data recording unit, 54
Recording medium, 55 data reading unit, 56 decoding unit, 57 dummy data removing unit.

Claims (20)

[Claims] 1. An encryption unit for encrypting a payload of a received transport packet by a block encryption method, and cipher block head information indicating whether or not the head of the payload is the head of the cipher block. Cipher block head information adding means for adding to the packet, recording means for recording the transport packet to which the cipher block head information is added in a recording medium, reading means for reading the transport packet from the recording medium, and the reading means It is analyzed based on the cipher block head information whether the head of the payload of the transport packet read by is the head of the cipher block, and the output starts from the transport packet whose head is the head of the cipher block. Cipher block top information analysis means , Digital signal recording and reproducing apparatus characterized by comprising a decoding means for decoding the transport packet outputted from the encryption block start information analyzer. 2. The cipher block head information adding means adds the cipher block head information by inserting the cipher block head information as a private data byte into an adaptation field of a transport packet. 1. The digital signal recording / reproducing apparatus according to 1. 3. The cipher block head information adding means adds the cipher block head information to the area immediately before the transport packet header for each transport packet. The digital signal recording / reproducing apparatus according to claim 1. 4. Data adding means for adding dummy data so that the payload length of the received transport packet becomes equal to an integral multiple of the block length in block encryption, and the data adding means adds dummy data. Encryption means for encrypting the payload by a block encryption method, recording means for recording a transport packet having the payload encrypted by the encryption means on a recording medium, and reading for reading the transport packet from the recording medium And a decoding unit for decoding the payload of the transport packet read by the reading unit, and a data deleting unit for deleting dummy data added to the payload decoded by the decoding unit. Digital signal recording / reproducing device. 5. An encryption unit for encrypting a payload of a received transport packet by a block encryption method, and cipher block head information indicating whether the head of the payload is the head of a cipher block or not. A digital signal recording device, comprising: cipher block head information adding means for adding to a packet; and recording means for recording a transport packet to which the cipher block head information is added on a recording medium. 6. The cipher block head information adding means adds the cipher block head information by inserting the cipher block head information as a private data byte into an adaptation field of a transport packet. 5. The digital signal recording device according to item 5. 7. The addition of cipher block head information by the cipher block head information adding means is performed by adding the cipher block head information to an area immediately before a transport packet header for each transport packet. The digital signal recording device according to claim 5. 8. Data adding means for adding dummy data so that the payload length of the received transport packet becomes equal to an integral multiple of the block length in block encryption, and the data adding means adds dummy data. A digital signal recording apparatus comprising: an encryption unit that encrypts the payload by a block encryption method; and a recording unit that records a transport packet having the payload encrypted by the encryption unit on a recording medium. 9. A record in which a transport packet is recorded in which a payload is encrypted by a block cipher method, and cipher block head information indicating whether or not the head of the payload is the head of a cipher block is recorded. A read unit that reads the transport packet from the medium, and analyzes whether or not the head of the payload of the transport packet read by the read unit is the head of the cipher block based on cipher block head information. Is provided with cipher block head information analysis means for starting output from the transport packet whose head is the head of the cipher block, and decoding means for decoding the transport packet output from the cipher block head information analysis means. And a digital signal reproducing device. 10. A record in which dummy data is added so that the payload length is equal to an integral multiple of the block length at the time of block encryption, and then the transport packet in which the payload is encrypted by the block encryption method is recorded. Reading means for reading the transport packet from the medium, decoding means for decoding the payload of the transport packet read by the reading means, and deleting dummy data added to the payload decoded by the decoding means A digital signal reproducing apparatus having a data deleting means for performing the same. 11. A payload of a received transport packet is encrypted by a block cipher method, and cipher block head information indicating whether the head of the payload is the head of a cipher block is added to the transport packet, The transport packet to which the cipher block head information is added is recorded on a recording medium, the transport packet is read from the recording medium, and the head of the payload of the transport packet read from the recording medium is the head of the cipher block. A digital signal recording / reproducing method characterized by analyzing whether or not there is a cipher block head information, and starting decoding from a transport packet in which the head of the payload is the head of the cipher block. 12. The addition of the cipher block head information comprises:
The digital signal recording / reproducing method according to claim 11, which is performed by inserting cipher block head information as private data bytes into an adaptation field of a transport packet. 13. The addition of the cipher block head information comprises:
12. The digital signal recording / reproducing method according to claim 11, wherein the method is performed by adding cipher block head information to an area immediately before a transport packet header for each transport packet. 14. Dummy data is added so that the payload length of a received transport packet is equal to an integral multiple of the block length in block encryption, and the payload with the dummy data is encrypted by a block cipher method. The transport packet having the encrypted payload is recorded on a recording medium, the transport packet is read from the recording medium, the payload of the transport packet read from the recording medium is decrypted, and the transport packet is decrypted. A method for recording / reproducing a digital signal, characterized in that the dummy data added to the payload is deleted. 15. A payload of a received transport packet is encrypted by a block cipher method, and cipher block head information indicating whether the head of the payload is the head of a cipher block is added to the transport packet. A digital signal recording method comprising recording a transport packet to which the cipher block head information is added on a recording medium. 16. The addition of the cipher block head information comprises:
16. The digital signal recording method according to claim 15, wherein the encryption block head information is inserted as a private data byte into an adaptation field of a transport packet. 17. The addition of the cipher block head information comprises:
16. The digital signal recording method according to claim 15, wherein the encryption block head information is added to the area immediately before the transport packet header for each transport packet. 18. The dummy data is added so that the payload length of the received transport packet is equal to an integral multiple of the block length at the time of block encryption, and the payload with the dummy data is encrypted by a block encryption method. And recording the transport packet having the encrypted payload on a recording medium. 19. A record in which a transport packet is recorded in which a payload is encrypted by a block cipher method, and cipher block head information indicating whether or not the head of the payload is the head of a cipher block is recorded. The transport packet is read from the medium, and it is analyzed based on the cipher block head information whether the head of the payload of the read transport packet is the head of the cipher block, and the head of the payload is the cipher block. A method for reproducing a digital signal, characterized in that decoding is started from a transport packet at the beginning. 20. A record in which dummy data is added so that the payload length is equal to an integral multiple of the block length at the time of block encryption, and then the transport packet in which the payload is encrypted by the block encryption method is recorded. A method of reproducing a digital signal, comprising: reading the transport packet from a medium, decoding the payload of the read transport packet, and deleting dummy data added to the decoded payload.