JPH07249264A - CD-ROM recording system, recording / playback system, and CD-ROM disc - Google Patents

Abstract

(57) [Abstract] [Purpose] To eliminate the need to manage key information for decrypting encrypted data recorded on a CD-ROM disc. Configuration: When necessary information is encrypted and recorded on a CD-ROM disc (1), key information necessary for decrypting this encrypted information is added to the CD-RO together with the encrypted information.
It is recorded in an appropriate area (3) in the M disc (1). A CD on which the encrypted information is recorded by such a recording method.
When reproducing the recorded contents of the ROM disc, the required key information is read out together with the encrypted information from the same CD-ROM disc, and the encrypted information can be decrypted only by these read information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a C-ROM for recording and reproducing various encrypted information on a CD-ROM disc.
The present invention relates to a D-ROM recording method, a CD-ROM recording / reproducing method, and a CD-ROM disc.

[0002]

2. Description of the Related Art In order to record a large amount of information, an optical recording / reproducing system using a laser beam or the like is known, and an optical disc for this purpose is a compact disc read-only memory, so-called CD-ROM disc. It is widely used in various fields as well as the audio field. CD
The ROM disk has been generally used as a read-only recording medium, but in recent years, a write-once type has also been developed and put into practical use.

By the way, in order to maintain confidentiality of information written on a CD-ROM disc, whether it is a read-only type or a write-once type, the information to be recorded is encrypted and the encrypted information is recorded on the CD-ROM disc. There are often demands to do so. As one technique for satisfying such a demand, for example, as described in the left column on page 4 of Japanese Patent Laid-Open No. 64-91256, encrypted data is recorded when user data is recorded on a CD-ROM disc. The encrypted data is recorded by adding a scramble process to the recorded data, the encrypted data is descrambled by the CD-ROM driver, and then the decrypted data (same as the encrypted data) and the encrypted data are written by the interface. A technique is known in which exclusive logic processing is performed and then output to a computer so that security of user data can be reliably performed. This prior art is
Since the required information is decrypted by using hardware, it has a great feature in that the processing time can be significantly shortened as compared with the case of using the processing by software.

[0004]

However, according to the above-mentioned prior art, since the key for decryption and the hardware are closely related, it is necessary to change the hardware if the key needs to be changed. It is necessary to change or change the contents of the decryption RAM, and a considerable cost is required for changing the key. Therefore, there is a tendency to continue to use the fixed key, which makes it relatively easy for a third party to obtain a clue for decrypting the recorded contents of the CD-ROM disc. This is because the format of the data to be recorded on the CD-ROM disc is standardized by ISO9660, so if you continue to use the same key, the data of the address where the specific contents defined by the standard are stored. The reason is that the key for decryption can be relatively easily guessed based on the content. Once the decryption key is known to a third party in this way, the remaining CD-
This causes a problem that the recorded contents of the ROM disk are also immediately decoded.

Another problem with the above-mentioned prior art is that the contents of the key for decryption must be managed in advance by an appropriate means, for example, a means such as being described in a codebook. The management is required separately, and the cost for managing the key information is generated. This problem is not only the above-mentioned conventional technique, but is a problem that generally occurs when recording encrypted data on a CD-ROM disc.

The object of the present invention is therefore to remedy one or some or all of the above-mentioned problems, inconveniences, etc. in the prior art CD-ROM.
Recording method, CD-ROM recording / reproducing method, and CD
-To provide a ROM disk.

The purpose of the present invention will be described in more detail by way of example.

A CD-ROM recording system and a CD-ROM recording / reproducing system which do not require the management of key information associated with a change of a key for encryption of information to be recorded on a CD-ROM disc are provided. thing.

To provide a CD-ROM disc which does not require management of key information for decrypting recorded encrypted data.

In order to prevent a third party from easily knowing the key for decrypting the encrypted and recorded data content,
A CD-ROM recording method and a CD, which allow a plurality of different keys to be used without increasing the cost.
-Provide a ROM recording / playback system.

The key required to encrypt the information to be recorded on the CD-ROM disc and to decrypt the encrypted information can be easily changed for each recording medium, and the key management is unnecessary. CD that can be
-To provide a ROM recording method, a CD-ROM recording / reproducing method, and a CD-ROM disc.

[0012]

In order to solve the above problems, the present invention provides a CD-ROM for encrypting required information and recording it on a CD-ROM disc which is an optical disc.
In the above recording method, the key information required to decrypt the encrypted information to be recorded on the CD-ROM disc is recorded in the CD-ROM disc together with the encrypted information.

The present invention also records / reproduces information on / from a CD-ROM for encrypting required information, recording it on a CD-ROM disc, and reading the recorded encrypted information from the CD-ROM disc for decryption. System, CD-R
The key information necessary for decrypting the encrypted information to be recorded on the OM disc is recorded in the CD-ROM disc together with the encrypted information, and the encryption recorded in the CD-ROM disc at the time of reproduction. It is characterized in that the encrypted information and the key information are read, and the encrypted information is decrypted using the key information read from the CD-ROM disc.

Further, according to the present invention, in a CD-ROM disc in which required information is encrypted and recorded, key information necessary for decrypting the recorded encrypted information is stored in the CD-ROM disc. It is characterized by being recorded.

[0015]

When the required information is encrypted and recorded in the CD-ROM disc, the key information necessary for decrypting the encrypted information read from the CD-ROM disc is also the CD-ROM. It is recorded on the disc. As a result, the encrypted information and the key information necessary for the decryption can always be managed integrally.

When reproducing the recorded contents of the CD-ROM disc on which the encrypted information is recorded by such a recording method, the required key information is the same as the encrypted information on the CD.
-The encrypted information can be decrypted only by the read information read from the ROM disk, and the required decryption is performed without paying special attention to the key information for decryption.

As described above, even if the key information is changed appropriately, the key information necessary for decrypting, that is, decrypting the recorded encrypted information is always recorded in the CD-ROM disc. It is not necessary to manage only the key information.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

1 and 2 show a CD-R according to the present invention.
CD-RO for recording required information on OM disc
An M recording system and a CD-ROM reproducing system forming a CD-ROM recording / reproducing system paired with the M recording system are shown.

First, the CD-ROM recording system 10 will be described with reference to FIG. 1. Reference numeral 11 is a storage device in which user data to be recorded on the CD-ROM disc 1 is stored in advance, and 12 is input various command data. A keyboard 13 for reading is a read controller for sequentially reading required user data designated by the keyboard 12 from the storage device 11, as will be described later, and the read controller 13
The required user data read by is sent to the encryption unit 14.

Prior to the description of the encryption unit 14, a recording method for recording desired user data on the CD-ROM disc 1 will be described with reference to FIG.

As shown in FIG. 3, the recording area of the CD-ROM disc 1 is the pregap area 2 and the ISO 96.
60 areas 4, and a large number of sectors S1, S2, S3 ... Are set in the ISO9660 area. Then, these sectors S1, S2, S3 ...
ISO9660 information exchange CD-R issued in 1988
JIS concerning OM volume and file structure
It is configured according to the data format based on X0606-1990.

Therefore, the data to be recorded is divided and sequentially stored in the 2048-byte user data area provided in each sector, and the content of one sector of data to be recorded on the CD-ROM disc 1 and its contents. Since the creation method is described in detail in the standard, detailed description thereof is omitted here, and it is simply stated that required user data is divided into sectors of ISO 9660 area 4 and recorded. Let me explain only the points. Further, in the ISO9660 area 4, an unused area can be defined by the definition of the data format, and it is used as the encryption key recording sector 3 of this embodiment.

Returning to FIG. 1, when the user data is divided into sectors to record the required user data in the CD-ROM disc 1, the keyboard 12 further records the user data to be recorded in which sector. It has a function of inputting encrypted sector information indicating whether to perform encryption. This encrypted sector information is sent from the keyboard 12 to the encryption key generator 15 in the encryption unit 14.

The encryption key generation unit 15 encrypts the user data based on the encrypted sector information sent from the keyboard 12 and generates a unique encryption key for the sector to be recorded for each required sector. It has a function of creating and holding a plurality of sets of encryption key data, which is a combination of information and the number information of the sector in which the encryption key is used.

These encryption key data are sent to the CD-ROM mastering device 18 at the timing when the encryption key recording sector 3 is recorded, and the CD-ROM mastering device 1 is sent.
These cipher key data are recorded in the cipher key recording sector 3 in the CD-ROM disc 1 by 8 (see FIG. 3).

On the other hand, the read control unit 13 reads the required user data stored in the storage device 11 for each sector and sends it to the encryption unit 16 of the encryption unit 14.
The encryption unit 16 can be configured by using a commercially available encryption IC. When receiving one sector of user data from the read control unit 13, the encryption unit 16 encrypts the encryption key for this sector to the encryption key generation unit 15. The encryption key request signal for requesting the encryption section 16 to send is output. The encryption key generation unit 15 responds to the encryption key request signal, and if the encryption key is prepared for the sector, that is, the user data to be recorded in the sector should be encrypted. If the command is given from 12, the encryption key prepared in advance for the sector is sent to the encryption unit 16. If the sector is not commanded to be encrypted and therefore the encryption key is not prepared, the encryption key generation unit 15 does not transmit the data to the encryption unit 16.

Therefore, in the encryption unit 16, the user data sent from the read control unit 13 for each sector is supplied from the encryption key generation unit 15 only for the sector for which the encryption is instructed. The data is encrypted using the encryption key, and the encrypted user data for one sector is sent to the interface unit 17. On the other hand, the user data to be recorded in the sector for which the encryption is not instructed is sent to the interface control unit 17 without being encrypted.

The interface control unit 17 sequentially sends the user data thus encrypted or not encrypted for each sector to the CD-ROM mastering device 18, and the user data for each sector is recorded on the CD-R.
The sectors S1, S2, ... Provided in the ISO9660 area 4 of the OM disc 1 are sequentially recorded by a predetermined procedure. In this embodiment, as can be seen from FIG. 3, the sector S
The user data recorded in 1, S2, S7, S9, ... Are not encrypted and the sectors S3, S6, S8 ...
-User data recorded in is encrypted. The sectors S4 and S5 are defined as unused areas and used as sectors for recording the encryption key. However, which sector of user data is encrypted and which unused area the encryption key is recorded in are not limited to those of this embodiment, and can be set appropriately. Also, instead of issuing a command from the keyboard 12 each time,
The sectors to be encrypted and recorded may be fixed such as the first to the 200th sectors.

In any case, the user data is CD-RO.
It is recorded as sector information in a predetermined area in the M disc 1 with or without being encrypted.
A great feature is that the encryption key required to decrypt the user data recorded in this way is recorded in a predetermined area in the same CD-ROM disc 1 as that. One of the advantages of this feature is that there is no need to manage the encryption key, and particularly when the encrypted data recorded on the CD-ROM disc 1 is reproduced and decrypted, the encryption key information is separately provided from the outside. It is not necessary to give.

In the above embodiment, the encryption key is different for each sector, but it goes without saying that all encryption sectors may have the same encryption key. Even if a large number of encryption keys are used, the complexity of encryption key management does not occur, so changing the encryption key for each sector makes it difficult for a third party to decrypt user data without increasing the cost of encryption key management. Therefore, it is possible to remarkably improve the confidentiality holding ability.

Next, referring to FIG. 2, the CD-RO shown in FIG.
A CD-ROM reproduction system 20 for reproducing and decoding user data encrypted and recorded on the CD-ROM disc 1 by the M recording system 10 will be described.

The CD-ROM reproduction system 20 is a CD-ROM.
CD-R for reading the recorded contents of the ROM disk 1
It has an OM drive device 21. By setting the CD-ROM disc 1 in the CD-ROM drive device 21, the cipher key data recorded in the cipher key recording sector 3 of the CD-ROM disc 1 is first read and sent to the interface control unit 22. . And
The read encryption key data is stored in the memory 25 in the decryption unit 23.

Thereafter, under the control of the interface control section 22, the ISO966 in the CD-ROM disc 1 is controlled.
The first 1 sector (S1) recorded in the 0 area 4 is C
The data is read by the D-ROM drive unit 21 and sent to the decoding unit 24 via the interface control unit 22. The decoding unit 24 can also be configured using a commercially available decoding IC. The decryption unit 24 requests the memory 25 to read the encryption key corresponding to this sector S1.

In this embodiment, the sector S1 is not an encrypted sector, so the encryption key corresponding to the sector S1 is not stored in the memory 25. Therefore, the memory 25
No encryption key information is output from the user, and the user data recorded in the sector S1 is directly decrypted by the decryption unit 24.
Are stored in the buffer memory 26. User data recorded in the sector S2 is processed in exactly the same manner.

When the recorded content of the sector S3 is input to the decryption unit 24, the encryption key necessary for decrypting the encrypted user data recorded in the sector S3 has a clue as to the number information in the encrypted key data. And the required encryption key is sent from the memory 25 to the decryption unit 24. The decryption unit 24 uses this encryption key to perform decryption processing of the encrypted user data recorded in the sector S3, and the decrypted user data is sent to the buffer memory 26.

In this way, the sectors S1, S2 ...
The encrypted user data recorded in (1) is decrypted by the encryption key supplied from the memory 25 and sent to the buffer memory 26. on the other hand,
The user data that has not been encrypted passes through the decryption unit 23 as it is and is stored in the buffer memory 26. Therefore, the required user data before encryption, that is, the decrypted user data can be retrieved from the buffer memory 26. In addition, the sector S4,
Although the encryption key is recorded in S5, it is an unused area in the data format and does not affect the extraction of the user data.

By using the system shown in FIGS. 1 and 2, at least the following effects are expected.

A CD-recording the encrypted user data with the encryption key used to encrypt the user data.
Since they are recorded together in the ROM disk 1, it is not necessary to separately manage the encryption key information. Therefore, not only the cost for managing the encryption key is unnecessary, but also the troublesomeness of the management is released.

Further, since the encrypted user data and the encryption key are recorded in the same CD-ROM disc 1, it is not necessary to separately record this change, no matter how the encryption key is changed, and the reproduction is performed. Sometimes, it is only necessary to read the encryption key required for decryption from the CD-ROM disc 1, so that the labor required for decryption is significantly simplified.

Since the CD-ROM disc 1 in which the user data is encrypted and recorded by this method has the encryption key information recorded therein, there is no concept of management of the encryption key information corresponding to the CD-ROM disc 1. The encryption key information management is completely unnecessary, and the user data can be reproduced and decrypted without paying attention to the encryption.

As described above, since the management cost of the encryption key information does not pose any problem, even if a different encryption key is used for each CD-ROM disc 1, no cost is generated and the confidentiality of the record is maintained. Retention can be significantly improved without incurring costs. This naturally applies to the configuration of this embodiment in which the encryption key is changed for each sector for one CD-ROM disc 1, and the encryption is low cost and extremely difficult for a third party to decrypt. It is possible to record.

Next, referring to FIGS. 4 to 6, a CD-ROM is executed by executing a predetermined recording control program and reproduction control program in the computer system.
Another embodiment in which recording and reproduction of the disc 1 are performed in the same manner as in the above-described embodiment will be described.

In FIG. 4, the user data stored in the external storage device 31 is encrypted and recorded on the CD-ROM disc 1, and the encrypted and recorded user data is recorded from the CD-ROM disc 1. 1 is a schematic configuration diagram of a CD-ROM recording / reproducing system 30 according to the present invention, which utilizes a computer system, for reading and reproducing.

In FIG. 4, the CD-ROM mastering device 1
8 and the CD-ROM drive device 21 are the same as the devices shown in FIGS. 1 and 2, and these devices 18, 21 and the external recording device 31 are connected to a computer system 32. Reference numeral 38 indicates a keyboard.

In this computer system 32, a central processing unit (CPU) 33, a random access memory (RAM) 34, a read-only memory (ROM) 35, and an input / output interface device (I / F) 36 are bus 37.
It is a well-known structure which is mutually connected by. Then, the recording control program and the reproduction control program stored in the ROM 35 are executed by the CPU 33 to encrypt the CD-ROM disc 1 in the same manner as in the case of the configuration shown in FIGS. Recording of user data and reproduction and decryption of the encrypted user data thus recorded are executed.

First, referring to FIG. 5, a CD-ROM
The recording operation of the recording / reproducing system 30 will be described.

When the execution of the recording control program is started, first in step 41, the encryption target sector is determined according to the data indicating the encryption target sector input from the keyboard 38. In the next step 42, an encryption key for each sector that requires encryption is generated, and the generated encryption key is stored in the RAM 34 as encryption key data. This encryption key data is the same as that described with reference to FIG.

In step 43, it is judged whether or not the CD-ROM mastering device 18 is in a writing state in the encryption key recording sector 3. When the CD-ROM mastering device 18 is in the writing state in the encryption key recording sector 3, the determination result of step 43 is YES and the process proceeds to step 44. In step 44, RAM
The encryption key data stored in the CD-ROM mastering device 1 passes through the CPU 33 and the I / F 36.
8 and the cipher key data is recorded in the cipher key recording sector 3 of the CD-ROM disc 1 set in the CD-ROM mastering device 18. Thereafter, in step 49, an end check is performed to determine whether or not all the required user data has been recorded. If all recording has not been completed, the process returns to step 43.

At the time when the recording of the encryption key data is completed, the determination result in step 43 is NO, and in step 45, one sector of user data is read from the external storage device 31. In the next step 46, it is judged whether or not the sector in which the read one sector of user data is to be recorded is an encryption target sector. If the sector in which the user data for one sector is to be recorded is the encryption target sector, the determination result of step 46 is YES.
Then, step 47 is entered.

In step 47, the process for encrypting the user data for one sector is performed using the encryption key for that sector among the encryption keys generated in step 42, and the encryption is performed in the next step 48. The processed user data for one sector is sent to the CD-ROM mastering device 18. The CD-ROM mastering device 18 records the received one sector of user data in a required sector.

If the decision result in the step 46 is NO, the step 47 is not executed, so that the user data for one sector read from the external storage device 31 is not subjected to the encryption process and is directly stored in the CD-ROM mastering device 18. It is sent and recorded in the required sector.

In this way, all the user data is on the CD
-When written in the ROM disk 1, the determination result of step 49 becomes YES, and the execution of the recording control program ends.

Next, the reproducing and decoding operations of the CD-ROM recording / reproducing system 30 for reading and reproducing the data recorded on the CD-ROM disk 1 in this way from the CD-ROM disk 1 will be described with reference to FIG. Will be described with reference to.

After the execution of the reproduction control program is started, first, at step 51, it is judged if the CD-ROM disc 1 is replaced. If there is replacement, step 52
Then, the encryption key data recorded in the encryption key recording sector 3 is read, and the process proceeds to step 53. If the determination result in step 51 is NO, since the encryption key data has already been read, step 52 is not executed and step 53 is entered.

At step 53, the CD-ROM drive unit 21 reads the data for one sector from the CD-ROM disc 1, and at step 54, whether the read data for one sector is the data of the decoding target sector. It is determined whether or not. If it is the decryption target sector, step 55 is entered, and the required decryption processing is performed using the encryption key data corresponding to the sector of the encryption key data already read in step 52, and step 56 Proceed to. On the other hand, 1 read in step 53
If the data for the sector is not the data for the sector to be decoded, step 5 is executed without executing step 55.
Enter 6.

In step 56, it is judged whether or not the reading of all the necessary sectors is completed, and if the reading of all the necessary sectors is not completed yet, step 53 is executed.
Return to. In this way, the data recorded on the CD-ROM disc 1 is read for each sector, and the decoding process is executed only for the sectors that need to be decoded. When the reading of all the necessary sectors is completed, the determination result in step 56 is YES, and the execution of the reproduction control program is completed. In this way, the CD-ROM disc 1
The user data recorded in can be reproduced and decrypted.

The CD-ROM recording / reproducing system 30 shown in FIG. 4 also has the same advantages as those of the system shown in FIGS.

[0059]

The effects of the present invention are as follows.

Since the encryption key information used for encrypting the data to be recorded on the CD-ROM disc is recorded on the CD-ROM disc for recording the encrypted data, the encryption key information is managed separately. You don't have to. Therefore, not only the cost for managing the encryption key information is unnecessary, but also the management is free from the trouble.

The encrypted data and the encryption key information are the same C
Since the data is recorded in the D-ROM disc, no matter how the encryption key is changed, it is not necessary to separately record and manage the information related to the change, and the data can be decrypted when reproducing the data in the CD-ROM disc. Since the required encryption key only has to be read from the CD-ROM disc, the labor required for decryption is greatly simplified.

The data is encrypted and recorded according to the method of the present invention, so that the CD-R in which the encrypted data and the encryption key information for decrypting the encrypted data are recorded together.
The OM disc does not have the concept of managing the encryption key information corresponding to the CD-ROM disc, all the encryption key information management becomes unnecessary, the management cost can be made unnecessary, and the encryption must be completely taken into consideration. It is possible to reproduce and decrypt user data without the need.

Since the management cost of the encryption key information is not a problem at all, even if a different encryption key is used for each CD-ROM disc, no management cost will be incurred, and the confidentiality of the record will be kept low. It can be significantly improved without causing it.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a recording system for a CD-ROM disc according to the present invention.

FIG. 2 is a configuration diagram showing an embodiment of a CD-ROM disc reproducing system according to the present invention.

FIG. 3 C used in the system of FIGS. 1 and 2.
CD-for explaining the recording method of the D-ROM disc
Explanatory drawing of the recording area in a ROM disc.

FIG. 4 is a configuration diagram showing another embodiment of a CD-ROM disc recording / reproducing system according to the present invention.

5 is a flowchart showing a recording control program executed in the computer system of FIG.

6 is a flowchart showing a reproduction control program executed in the computer system of FIG.

[Explanation of symbols]

 1 CD-ROM Disc 3 Encryption Key Recording Sector 4 ISO9660 Area 10 CD-ROM Recording System 11 Storage Device 14 Encryption Unit 15 Encryption Key Generation Unit 16 Encryption Unit 20 CD-ROM Playback System 23 Decryption Unit 24 Decryption Unit 30 CD-ROM recording / reproducing system S1 to S9 sectors

Continuation of the front page (72) Inventor Toshinori Taniguchi 15-1 Naeshiro-cho, Mizuho-ku, Aichi Prefecture Nagoya City Brother Industries, Ltd.

Claims (3)

[Claims] 1. In a CD-ROM recording method for encrypting required information and recording it on a CD-ROM disc, key information necessary for decrypting encrypted information to be recorded on a CD-ROM disc. Together with the encrypted information and the C
A CD-ROM recording method characterized by recording in a D-ROM disc. 2. The required information is encrypted and recorded on a CD-ROM disc, and the recorded encrypted information is recorded on a CD-RO.
CD-RO for reading from M disc and decoding
In the M recording / reproducing method, key information necessary for decrypting the encrypted information to be recorded on the CD-ROM disc is recorded together with the encrypted information in the CD-ROM disc, and the CD is reproduced at the time of reproduction. -Read the encrypted information and key information recorded in the ROM disc, and read the CD-R
A CD-ROM recording / reproducing system characterized in that the encrypted information is decrypted by using the key information read from the OM disc. 3. A CD-ROM disc in which required information is encrypted and recorded, and key information necessary for decrypting the recorded encrypted information is recorded in the CD-ROM disc. CD-ROM characterized by
disk.