JP2000231760A - Device and method to record information, device and method to reproduce information and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decode ciphered data using an old generation secret key even though the secret key is updated. SOLUTION: In an optical disk 7, the generation of a sector key Eks, in which ciphered contents are written, is written. A generation discriminating circuit 49 discriminates the generation of the key Eks used in the ciphering. A Km memory 44 outputs a master key Km corresponding to the discriminated generation to an Ekd decoding circuit 46. The circuit 46 decodes a ciphered disk key Ekd by using the key Km. And Ekd decoding circuit 47 decodes the ciphered sector key Eks by using a disk key Kd to obtain a sector key Ks. A contents data decoding circuit 48 decodes ciphered contents data by employing the key Ks.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording apparatus and method, an information reproducing apparatus and method, and a recording medium, and more particularly, to a method for securely encrypting copyrighted content without unauthorized use. The present invention relates to an information recording apparatus and method, an information reproducing apparatus and method, and a recording medium that enable recording or reproduction of content on a recording medium.

[0002]

2. Description of the Related Art In recent years, recording apparatuses and recording media for digitally recording information have become widespread. These recording devices and recording media, for example, record and reproduce video and music data without deterioration, so that data can be copied many times while maintaining its quality. However, for video and music copyright holders, there is a risk that video and music data for which they have a copyright may be illegally copied many times while maintaining their quality and distributed to the market. . Therefore, there is a demand for preventing the copyrighted data from being illegally copied on the recording device and the recording medium side.

For example, in a mini disc (MD) (trademark) system, SCMS (Serial Copy Management System) is used.
A method called is used. This is because the music data is copied free, copy once allowed, or cop depending on the information transmitted along with the music data by the digital interface.
Indicates which data is yprohibited (copy prohibited). When the mini disc recorder receives music data from the digital interface, it detects SCMS. If this is copy prohibited, the music data is not recorded on the mini disc.If copy once allowed, this is set to copy prohibited. The data is changed and recorded together with the received music data, and if it is copy free, it is recorded as it is with the received music data.

[0004] In this manner, in the mini-disc system, the use of the SCMS is used to prevent unauthorized copying of copyrighted data.

[0005] Another example of preventing unauthorized copying of copyrighted data is Digital Versatile.
There is a content scramble system in a Disk (DVD) (trademark) system. In this system, all the copyrighted data on the disk is encrypted,
Only licensed recording devices are given encryption keys,
As a result, the encrypted data can be decrypted and meaningful data can be obtained. Then, the recording device is designed so as to comply with the operation rules such as not performing unauthorized copying when receiving a license. In this way, in the DVD system, unauthorized copying of copyrighted data is prevented.

However, in the system adopted by the mini-disc system, if the SCMS is copy once allowed, a recording device that does not comply with the operation rules such as changing this to copy prohibited and recording it together with the received data, If manufactured improperly, copying due to it cannot be prevented.

[0007] The system adopted by the DVD system is effective for ROM (Read Only Memory) media, but is a RAM (Random Ac- cess) in which a user can record data.
cess Memory) media is not effective. In the case of RAM media, an unauthorized person can illegally copy all the data on the disk to a new disk even if the encryption cannot be decrypted, thereby renewing the disk that can be operated with a licensed recording device. Because it can be made in.

The applicant of the present invention has disclosed in Japanese Patent Application No. 10-25310, filed earlier, information for identifying an individual recording medium (hereinafter referred to as medium identification information) together with other data. And a method to prevent only the licensed device from accessing the medium identification information of the recording medium. In this method, data on a recording medium is encrypted using medium identification information and a secret key (master key) obtained by receiving a license, and even if an unlicensed device reads the encrypted data, , That data makes no sense. When each device receives a license, its operation is stipulated to prevent unauthorized duplication.

[0009] Unlicensed equipment cannot access the medium identification information, and the medium identification information is an individual value for each medium. Even if the information (encrypted) is copied to a new medium, the information on the medium created in this way can be correctly read not only by an unlicensed device but also by a licensed device. Can not. In this way, unauthorized duplication is prevented.

[0010]

The secret key obtained by the license in the above proposal has to be common to all devices. This is a necessary condition for a medium recorded on one device to be reproducible on another device (to ensure interoperability).

[0011] For this reason, if one device is attacked by an attacker and the secret key held by that device is revealed, the secret keys of all devices are exposed. That is, there is a problem that not only the data recorded before the secret key was exposed but also the data recorded after the secret key was exposed would be decrypted using the exposed private key. there were.

In order to prevent such a situation, it is conceivable to update the secret key stored in the device when it is found that the secret key has been exposed or periodically. By using the updated secret key, data encrypted with the secret key will not be decrypted with the revealed secret key.

[0013] However, as described above, when the secret key stored in the device is updated, there is a problem that data encrypted using the old secret key cannot be decrypted.

The present invention has been made in view of such a situation, and a plurality of secret keys including an old generation key can be stored, or an old generation secret key can be created from the latest generation secret key. By doing so, even if the secret key stored in the device is updated, the encrypted data can be decrypted using the secret key of the old generation.

[0015]

According to a first aspect of the present invention, there is provided an information recording apparatus comprising: a storage unit for storing at least one or more generations of secret keys;
Generating means for generating a second key, first encrypting means for encrypting a second key used for encrypting data to be recorded on a recording medium with a first key, and first encrypting means. A first recording unit that records the encrypted second key together with the generation number of the first key on a recording medium.

According to a seventh aspect of the present invention, there is provided an information recording method, comprising: a storage control step of controlling storage so as to store at least one or more generations of secret keys; and a first key based on medium identification information of the recording medium and the secret keys. , A first encryption step of encrypting a second key used for encrypting data to be recorded on the recording medium with the first key, and a process of the first encryption step. The encrypted second key,
And a first recording control step of controlling recording so as to record the information on the recording medium together with the generation number of the first key.

According to a thirteenth aspect of the present invention, a program for a recording medium according to a thirteenth aspect includes a storage control step of controlling storage so as to store at least one or more generations of a secret key; A generating step of generating a key, an encrypting step of encrypting a second key used for encrypting data to be recorded on the recording medium with the first key,
The second key encrypted by the processing of the encryption step is
And a recording control step of controlling recording so as to record on the recording medium together with the generation number of the first key.

According to a fourteenth aspect of the present invention, there is provided an information reproducing apparatus, comprising: storage means for storing at least one or more generations of secret keys; and a second key encrypted by a first key, a second key encrypted by a first key. First reading means for reading the generation number of the first key obtained by encrypting the key and medium identification information of the recording medium, and a secret key corresponding to the medium identification information and the generation number read by the first reading means And a first decryption unit that decrypts the second key with the first key generated by the generation unit.

An information reproducing method according to claim 18, wherein a storage control step of controlling storage so as to store at least one or more generations of secret keys, and a first key encrypted with a first key from a recording medium. A first reading step of reading out the second key, the generation number of the first key obtained by encrypting the second key, and the medium identification information of the recording medium; and the medium identification read by the processing of the first reading step. A generation step of generating a first key from a secret key corresponding to information and a generation number; and a first key generated by the processing of the generation step.
And a first decryption step of decrypting the second key.

[0021] In the storage medium according to the present invention, the storage control step of controlling storage so as to store at least one or more generations of secret keys, and the storage medium is encrypted with the first key from the storage medium. A reading step of reading the second key, the generation number of the first key obtained by encrypting the second key, and the medium identification information of the recording medium; and the medium identification information and the generation number read by the processing of the reading step. The method includes a generation step of generating a first key from a corresponding secret key, and a decryption step of decrypting a second key with the first key generated by the processing of the generation step.

The recording medium according to claim 23 is encrypted with medium identification information that is a value unique to the recording medium, and with the first key generated by the medium identification information and a secret key from the information recording device. , A second key used for encrypting data is recorded, and the second key encrypted with the first key is recorded in association with the generation number of the first key. It is characterized by having.

[0022] The information recording apparatus according to claim 1, and claim 7.
In the information recording method according to the present invention, and at least one generation of the secret key is stored, and the first key is generated from the medium identification information and the secret key of the recording medium. A second key used for encrypting data to be recorded on the recording medium is encrypted with the first key, and the encrypted second key is recorded on the recording medium together with the generation number of the first key. You.

In the information reproducing apparatus according to the fourteenth aspect, the information reproducing method according to the eighteenth aspect, and the program of the recording medium according to the twenty-second aspect, at least one or more generations of secret keys are stored and recorded. From the medium, the second key encrypted with the first key, the generation number of the first key encrypted with the second key, and the medium identification information of the recording medium are read, and the read medium is read. A first key is generated from the secret key corresponding to the identification information and the generation number, and the second key is decrypted with the generated first key.

In a recording medium according to a twenty-third aspect,
A medium identification information that is a value unique to the recording medium, and a second key used to encrypt data, which is encrypted with the medium identification information and a first key generated by a secret key from the information recording device. Are recorded, and the second key encrypted with the first key is recorded in association with the generation number of the first key.

[0025]

Embodiments of the present invention will be described below. FIG. 1 shows a configuration example of an optical disk recording / reproducing apparatus to which the present invention is applied. The input unit 1 includes a button, a switch, a remote controller, and the like, and outputs a signal corresponding to the input operation when the user performs an input operation. For example, the control circuit 2 configured by a microcomputer or the like controls the entire apparatus according to a predetermined computer program stored.

The recording / reproducing circuit 3 includes an encryption unit 4 and a decryption unit 5
The decoding unit 5 decodes the data reproduced from the optical disk 7 by the pickup 6 and outputs the data to the outside as a reproduction signal. Upon receiving the supply of the recording signal from the outside, the encryption unit 4 encrypts the signal, supplies it to the pickup 6, and records it on the optical disk 7.

The pickup 6 records and reproduces data by irradiating the optical disk 7 with a laser beam. The spindle motor 9 is controlled by the servo circuit 8,
The optical disk 7 is rotated. The servo circuit 8 drives the spindle motor 9 to rotate the optical disk 7 at a predetermined speed (for example, at a constant linear speed). The servo circuit 8 also controls a thread servo in addition to tracking and focusing of the pickup 6. The random number generation circuit 10 generates a predetermined random number under the control of the control circuit 2.

On the optical disk 7, data having a structure as shown in FIG. 2 is recorded. In the lead-in area of the optical disk 7, an ED obtained by encrypting the ID of the optical disk 7 (hereinafter referred to as DiscID) with a predetermined M-sequence code.
An encrypted disk key EKd obtained by encrypting the disk key Kd associated with the iscID and the generation number with the effective master key Kem is recorded. In the example shown in FIG. 2, the encrypted disk keys EKd of the generation numbers 1 and 3 are recorded.

The Disc ID is a unique value for identifying the optical disk 7. The disk key Kd is a unique value for each optical disk 7 and also a unique value that differs for each generation number of the master key Km of the recording / reproducing circuit 3. That is, every time the generation of the master key Km is updated,
Disk key Kdj corresponding to each generation (j = 1,2,3
...) (Here, j of Kdj indicates a generation number, but it is also described as Kd if there is no particular need to distinguish them).

The M-sequence code has "0" and "
The binary of 1 "is a pseudo-random binary signal (a kind of pseudo-random number) appearing at random, and DiscID is, for example, TOC (Table Of Contents) such as file name and directory information.
The data is encrypted by being embedded based on a predetermined M-sequence code set in advance. That is, DiscID
Is recorded as the time lag of the edge of the TOC data.
When such encryption is performed, the TOC data can be read without the M-sequence code (the TOC data is not encrypted), but the DiscID cannot be read (decoded) without the M-sequence code. . The present applicant has previously proposed a technique relating to such M-sequence code-based encryption as Japanese Patent Application No. 09-288960. The predetermined M-sequence code is given to a licensee together with a master key Km to be described later when a proper license is received from a copyright holder.

The effective master key Kem is obtained by combining the master key Km and the DiscID according to the following equation (1).
Calculated by applying the sh function.

Effective master key Kem = hash (master key Km + DiscID) (1) Here, the master key Km is a secret key given only to a person (optical disk recording / reproducing apparatus) properly licensed by a copyright holder or the like. is there. Here, for example, A and B
Means that when each is 32 bits, B is connected after A to form 64-bit data.

Each sector Si in the data area of the optical disk 7
(i = 1, 2,...) is composed of a header and a main data part, and the header includes an encrypted sector key EKsi (i = 1, 2,...) obtained by encrypting the sector key Ksi with the disk key Kd. (Here, i of Ksi indicates the number of the sector, and since the sector key is different for each sector, it is described as Ksi, but it is also described as Ks when there is no particular need to distinguish it.)

Since the optical disk 7 records a plurality of generations of the disk key Kd (encrypted by the effective master key Kem), it is possible to determine which generation of the disk key was used for the encryption. For identification, the generation number of the used disk key Kd is also recorded in the header of each sector in the data area. FIG.
In the example shown in FIG. 7, the generations of the disk key Kd recorded on the optical disk 7 are generation number 1 and generation number 3, and therefore only the generation number 1 and generation number 3 disk key Kd are used and the sector key EKs Is encrypted.

The main data section stores encrypted content data obtained by encrypting the content data with the sector key Ksi.

FIG. 3 shows an example of the configuration of the encryption unit 4. The DiscID encryption / decryption circuit 21 converts the encrypted disc ID read from the optical disc 7, that is, EDiscID, into M
It decodes based on the M-sequence code supplied from the sequence code generation circuit 22 to generate a DiscID. The DiscID encryption / decryption circuit 21 also converts the random number generated from the random number generation circuit
Based on the M-sequence code supplied from the M-sequence code generation circuit 22 and received as an scID, as described above, it is encrypted so as to be embedded in the input TOC information, and an EDiscID is generated and recorded on the optical disc 7.

The M-sequence code generation circuit 22 is composed of, for example, a plurality of flip-flops connected in series and an Exclusive-OR circuit, or
It can also be composed of ROM, EEPROM, etc.

The Km memory 24 of the Kem generation module 23
Stores a plurality of master keys Km. The hash function circuit 25 of the Kem generation module 23 generates a combination of the master key Km and the DiscID, and calculates the effective master key Kem by applying the hash function thereto.

The Kd encryption / decryption circuit 26 decrypts the encrypted disk key EKd read from the optical disk 7 with the effective master key Kem to generate a disk key Kd. The Kd encryption / decryption circuit 26 also includes the random number generation circuit 10
Receives the random number generated from as the disk key Kd,
Encrypted with the effective master key Kem to generate an encrypted disk key EKd, which is recorded on the optical disk 7.

The Ks encryption circuit 27 receives the random number generated by the random number generation circuit 10 as the sector key Ks, encrypts the random number with the disk key Kd, generates an encrypted sector key EKs, and records it on the optical disk 7. The content data encryption circuit 28 encrypts the content data with the sector key Ks and records the content data on the optical disc 7.

In the example of FIG. 3, the encryption circuit is
Ks encryption circuit 27 and content data encryption circuit 28
Are described as separate configurations, respectively,
Of course, it may be configured as one encryption circuit (the same applies to the decryption circuit).

Next, FIG. 4 shows a configuration example of the decoding unit 5.
The EDiscID decoding circuit 41 decodes the EDiscID read from the optical disc 7 based on the M-sequence code supplied from the M-sequence code generation circuit 42 to generate a DiscID. M
The sequence code generation circuit 42 has the same configuration as that of the M sequence code generation circuit 22 and generates the same M sequence code as that of the M sequence code generation circuit 22.

The Km memory 44 of the Kem generation module 43
Stores a plurality of master keys Km. The hash function circuit 45 of the Kem generation module 43 generates a combination of the master key Km and the DiscID, and calculates the effective master key Kem by applying the hash function to the combination. This Kem generation module 4
3 has the same configuration as the Kem generation module 23, and may use both of them. Here, the Km memory 24
And the master key stored in the Km memory 44, FIG.
This will be described with reference to FIG.

The master keys Km are stored in the Km memories 24 and 44.
Are stored in ascending order of generation. FIG. 5 shows an example in which master keys Km of generation numbers 1 to 3 are stored. The new generation master key Km is distributed, for example, via the optical disk 7 on which the new generation master key Km is recorded, or is distributed via a network such as the Internet. For each device (optical disk recording / reproducing device) that stores the master key Km, an encryption key unique to the device is held, and the master key Km stored in the Km memories 24 and 44 is stored after being encrypted with the encryption key. You may do it.

The EKd decryption circuit 46 decrypts the encrypted disk key EKd read from the optical disk 7 with the effective master key Kem to calculate the disk key Kd. The EKs decoding circuit 47 reads each sector Si from the optical disc 7.
Read out the encrypted sector key EKs recorded in the header of, and decrypt with the disk key Kd to calculate the sector key Ks. The content data decoding circuit 48
Decrypts the encrypted content data read out from the storage device with the sector key Ks.

The generation discriminating circuit 49 reads the header of the data area, judges which generation of the sector key Ks is used to encrypt the content data recorded in the main data portion, and determines the result of the judgment by Km. Output to the memory 44. The Km memory 44 outputs the stored master key Km to the hash function circuit 45 in accordance with the data on the generation output from the generation determination circuit 49.

Next, the processing procedure in the encryption unit 4 when content data is recorded on the optical disk 7 will be described with reference to FIG.
This will be described with reference to the flowchart of FIG. In step S1, the DiscID encryption / decryption circuit 21 determines whether or not EDiscID has been written in the lead-in area of the optical disk 7, and the Kd encryption / decryption circuit 26 determines whether or not the EdID has been written in the lead-in area of the optical disk 7. It is determined whether the encrypted disk key EKd has been written. If it is determined that both the EDiscID and the encrypted disc key EKd have not been written, the process proceeds to step S2, where the random number generation circuit 10
A 28-bit random number is generated and output to the DiscID encryption / decryption circuit 21 as a DiscID.

In step S3, the DiscID encryption / decryption circuit 21 outputs the DiscID supplied from the random number generation circuit 10.
Is encrypted based on the M-sequence code supplied from the M-sequence code generation circuit 22 so as to be embedded in the TOC information, as described above, to generate an EDiscID.
Record in the lead-in area. The M-sequence code supplied by the M-sequence code circuit 22 is given when a proper license is received from the copyright holder.

Next, in step S4, the hash function circuit 25 of the Kem generation module 23 reads the latest generation master key Km from the Km memory 24 of the Kem generation module 23. Hash function circuit 25 of Kem generation module 23
Calculates the effective master key Kem in step S5 by applying the hash function to the combination of the DiscID of the optical disk 7 and the master key Km read from the Km memory 24 in accordance with the above equation (1), and calculates the Kd encryption / decryption circuit. 26.

Next, in step S6, the random number generation circuit 10 generates a 40-bit random number,
Is output to the Kd encryption / decryption circuit 26. The Kd encryption / decryption circuit 26 determines in step S7 that the random number generation circuit 1
0 is supplied to the hash function circuit 25.
Then, the encrypted disk key EKd is generated by encrypting with the effective master key Kem received from the optical disk 7, and is recorded in the lead-in area of the optical disk 7.

On the other hand, in step S1, the ED is
If it is determined that the iscID and the encrypted disk key EKd have been written, the process proceeds to step S8, where the DiscID encryption / decryption circuit 21 sends the EDiscI read from the optical disk 7.
D is decoded with the M-sequence code supplied from the M-sequence code generation circuit 22 to obtain a DiscID.

In step S9, the hash function circuit 25 of the Kem generation module 23
Of the master key Km of the latest generation from the Km memory 24 of FIG. In step S10, the hash function circuit 25 of the Kem generation module 23 calculates the effective master key Kem by applying the hash function to the combination of the DiscID of the optical disk 7 and the master key Km according to the above-described equation (1), and performs Kd encryption. It is supplied to the decoding circuit 26.

Next, in step S11, the Kd encryption / decryption circuit 26 decrypts the encrypted disk key EKd read from the optical disk 7 with the effective master key Kem received from the hash function circuit 25, and the disk key Kd Get. The Kd encryption / decryption circuit 26 receives the disk key Kd
Is output to the Ks encryption circuit 27.

After the processing in step S7 or S11, in step S12, the random number generation circuit 10 generates a 40-bit random number and outputs it as a sector key Ks to the Ks encryption circuit 27 and the content data encryption circuit 28. . The Ks encryption circuit 27 determines in step S13 that Kd
The encryption / decryption circuit 26 (when the encrypted disk key EKd is recorded on the optical disk 7) or the random number generation circuit 1
0 (when the encrypted disk key EKd is not recorded on the optical disk 7), encrypts the sector key Ks received from the random number generating circuit 10 to generate an encrypted sector key EKs. Ks encryption circuit 2
7 also stores the encrypted sector key EKs on the optical disk 7
Is recorded in the header of the data area.

Next, in step S14, the content data encryption circuit 28 encrypts the content data using the sector key Ks and records it in the main data section of the data area of the optical disk 7.

In step S15, each circuit of the encryption unit 4 determines whether or not all the content data has been recorded. If it is determined that all the content data have not been recorded yet, the process proceeds to step S16, where each circuit of the encryption unit 4 accesses a sector of the optical disc 7 on which data has not been recorded, and returns to step S12. ,
Hereinafter, the same processing is repeated. On the other hand, in step S15,
When it is determined that all the content data has been recorded, each circuit of the encryption unit 4 ends all the recording processes.

As described above, when receiving an appropriate license from the copyright holder, the encrypted DiscID is decrypted with the given predetermined M-sequence code, and the DiscID is obtained. Is recorded on the recording medium. Thereby, for example, even if a person who is not properly licensed from the copyright holder copies the content data of this disc to an existing recording medium (recording medium on which DiscID is not recorded), the content data is It cannot be reproduced as meaningful information.

Next, referring to the flowchart of FIG.
The reproduction process of the content data performed by the decoding unit 5 will be described. In step S21, the EDiscID decoding circuit 41 receives the EDiscID, which is the encrypted DiscID, read from the lead-in area of the optical disk 7. Further, the generation determining circuit 49 receives a header of the data area of the optical disk 7.

The EDiscID decoding circuit 41 determines in step S22
In step, based on the M-sequence code supplied from the M-sequence code generation circuit, the EDiscID is decoded to obtain a DiscID, and then output to the hash function circuit 45 of the Kem generation module 43.

Next, in step S23, the hash function circuit 45 of the Kem generation module 43 receives the DiscID output from the EDiscID decoding circuit 41 and reads out the disc ID from the Km memory 44 in accordance with the generation determined by the generation determining circuit 49. The received master key Km is received, and the hash function is applied to the combination of the disc ID of the optical disc 7 and the master key Km according to the above-described equation (1), so that the effective master key Ke is obtained.
m is calculated and supplied to the EKd decoding circuit 46.

In step S24, the EKd decoding circuit 4
6 receives the encrypted disk key EKd read from the lead-in area of the optical disk 7. EKd decoding circuit 46
Decrypts the read encrypted disk key EKd with the effective master key Kem received from the hash function circuit 45 to calculate the disk key Kd and outputs it to the EKs decryption circuit 47 in step S25.

Next, in step S26, the EKs decryption circuit 47 receives the encrypted sector key EKsi (i = 1, 2,...) Of each sector read from the data area of the optical disk 7. In step S27, the EKs decryption circuit 47 decrypts the read encrypted sector key EKsi with the disk key Kd received from the EKd decryption circuit 46, calculates the sector key Ksi, and outputs it to the content data decryption circuit 48. .

In step S28, the content data decryption circuit 48 receives the encrypted content data read from the optical disk 7. In step S29, the content data decryption circuit 48 decrypts the read encrypted content data using the sector key Ksi received from the EKs decryption circuit 47, and outputs the decrypted content data as a reproduction signal.

Next, in step S30, the decoding unit 5
Each circuit determines whether or not all the content data has been read from the data area of the optical disk 7. If it is determined that all the content data has not been read yet, the process proceeds to step S31, and each circuit of the decoding unit 5 receives the supply of the data of the next sector of the optical disk 7 that has not been read out. The processing after step S26 is repeated. When it is determined that all content data has been read, each circuit of the decoding unit 5 ends all the reproduction processing.

As described above, the ID of the recording medium is generated, encrypted with a predetermined M-sequence code, and recorded on the recording medium.
The recording medium can be accessed. Further, by storing a plurality of master keys Km, it is possible to decrypt (reproduce) even data encrypted with an old generation master key MK.

In the above-described embodiment, Km
Although the memories 24 and 44 store the master key Km for each generation, the master key Km of the past generation may be generated from the master key Km of the latest generation. That is, a one-way function f is stored in each device, and the latest generation master key Km is substituted for the one-way function f, thereby creating a master key Km one generation before. When an older master key Km is required, the master key Km is generated for each previous generation by successively assigning the master key Km to the one-way function f repeatedly.

As the one-way function f, for example, Ha
It is possible to use the sh function or MD5 (Message Diget 5).

The present invention is also applicable to the case where data is recorded or reproduced on a recording medium other than an optical disk.

The series of processes described above can be executed by hardware, but can also be executed by software. When a series of processing is executed by software, a program constituting the software can execute various functions by installing a computer built into dedicated hardware or installing various programs. It is installed from a recording medium into a possible general-purpose personal computer or the like.

This recording medium is separate from the computer.
A magnetic disk (including a floppy disk) on which the program is recorded, an optical disk (CD-ROM (Compact Disk-Read) distributed to provide the program to users.
It is not only composed of package media consisting of magneto-optical disks (including MD (Mini-Disk)), semiconductor memory, etc., including Only Memory), DVD (Digital Versatile Disk), but also pre-installed in the computer. And a hard disk or the like provided with the program for recording the program.

[0071]

According to the information recording apparatus and method, the information reproducing apparatus and method, the program of the recording medium and the recording medium according to the present invention, a predetermined generation of secret key is stored and recorded on the recording medium. Since a secret key corresponding to the generation of the secret key that encrypted the data is generated, and the generated secret key is used to decrypt the data encrypted and recorded on the recording medium, Even if the recorded secret key is updated, it is possible to decrypt the data encrypted with the old secret key.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of an optical disk recording / reproducing apparatus to which the present invention is applied.

FIG. 2 is a diagram illustrating data recorded on an optical disc.

FIG. 3 is a diagram showing an internal configuration of an encryption unit 4 of FIG. 1;

FIG. 4 is a diagram showing an internal configuration of a decoding unit 5 in FIG. 1;

FIG. 5 is a diagram illustrating data stored in a Km memory.

FIG. 6 is a flowchart illustrating the operation of the encryption unit 4 of FIG. 1;

FIG. 7 is a flowchart illustrating an operation of the decoding unit 5 of FIG. 1;

[Explanation of symbols]

Reference Signs List 1 input section, 2 control circuit, 3 recording / reproducing circuit, 4 encryption section, 5 decoding section, 6 pickup, 7 optical disk, 8 servo circuit, 9 spindle motor, 10 random number generation circuit, 21 DiscID encryption / decryption circuit, 22 M Sequence code generation circuit, 23 Kem generation module, 24 Km
Memory, 25 hash function circuit, 26 Kd encryption / decryption circuit, 27 Ks encryption circuit, 28 content data encryption circuit, 41 EDiscID decryption circuit, 42 M-sequence code generation circuit, 43 Kem generation module, 44 Km memory,
45 hash function circuit, 46 EKd decoding circuit, 47 EKs decoding circuit, 48 content data decoding circuit, 49 generation discriminating circuit

Claims (23)

[Claims] 1. An information recording apparatus for recording data on a removable recording medium, comprising: storage means for storing at least one or more generations of secret keys; first information from medium identification information of the recording medium and the secret key; Generating means for generating a key; first encrypting means for encrypting a second key used for encrypting the data recorded on the recording medium with the first key; and the first encryption An information recording apparatus comprising: a first recording unit that records the second key encrypted by the encryption unit on the recording medium together with a generation number of the first key. 2. The apparatus according to claim 2, further comprising: first random number generating means for generating the medium identification information as a random number;
Read out the second key from the recording medium, and if the recording medium does not have the second key, send the second key to the first random number generating means. The information recording apparatus according to claim 1, wherein a random number is generated. 3. The recording medium is divided into a plurality of recording units, and a second random number serving as a third key for encrypting the data recorded in the recording unit is generated for each recording unit. Random number generation means; second encryption means for encrypting the third key generated by the second random number generation means with the second key; and encryption by the second encryption means. 3. The information recording apparatus according to claim 2, further comprising: a second recording unit that records the third key obtained in a recording unit of the recording medium. 4. The method according to claim 1, wherein the second key has a unique value for each recording medium, and that the second key is newly generated by the first random number generating means every time the generation of the secret key changes. The information recording apparatus according to claim 2, wherein 5. The information recording apparatus according to claim 1, wherein the storage unit stores the secret key of one generation and generates the secret key of another generation by calculation. 6. The information recording apparatus according to claim 1, wherein a generation number of the first key corresponds to a generation of the secret key used in the generation unit. 7. An information recording method for an information recording apparatus for recording data on a removable recording medium, comprising: a storage control step of controlling storage so as to store at least one or more generations of secret keys; Generating a first key from medium identification information and the secret key; and first encrypting a second key used for encrypting data to be recorded on the recording medium with the first key. An encryption step; and a first control that controls recording such that the second key encrypted by the processing of the first encryption step is recorded on the recording medium together with a generation number of the first key. And a recording control step. 8. The method according to claim 1, further comprising a first random number generating step of generating the medium identification information as a random number. In the processing of the first encrypting step, the recording medium has the second key in advance. The second key is read from the recording medium, and if the recording medium does not have the second key, the random number serving as the second key is processed by the first random number generation step. 8. The information recording method according to claim 7, wherein the information is generated. 9. The recording medium, wherein the recording medium is divided into a plurality of recording units, and a second random number serving as a third key for encrypting the data recorded in the recording unit is generated for each recording unit. A random number generation step; a second encryption step of encrypting the third key generated by the processing of the second random number generation step with the second key; 9. The information recording apparatus according to claim 8, further comprising: a second recording control step of controlling recording so that the third key encrypted by the processing is recorded in a recording unit of the recording medium. Method. 10. The second key has a unique value for each of the recording media, and is newly generated by the processing of the first random number generating step each time the generation of the secret key changes. The information recording method according to claim 8, wherein: 11. The processing of the storage control step includes:
8. The information recording method according to claim 7, wherein storage is controlled so as to store the secret key of a generation, and the secret key of another generation is generated by calculation. 12. The information recording method according to claim 7, wherein the generation number of the first key corresponds to the generation of the secret key used in the processing of the generation step. 13. A program for an information recording device for recording data on a removable recording medium, comprising: a storage control step of controlling storage so as to store at least one or more generations of secret keys; Generating a first key from the medium identification information and the secret key, and encrypting a second key used for encrypting data to be recorded on the recording medium with the first key. And the second step encrypted by the processing of the encrypting step.
A recording control step of recording the key in the recording medium together with the generation number of the first key. 14. An information reproducing apparatus for reproducing data recorded on a removable recording medium, comprising: storage means for storing at least one or more generations of secret keys; The second key,
First reading means for reading the generation number of the first key obtained by encrypting the second key, and medium identification information of the recording medium; and the medium identification information read by the first reading means. Generating means for generating the first key from the secret key corresponding to the generation number; and first decrypting means for decrypting the second key with the first key generated by the generating means. An information reproducing apparatus comprising: 15. The recording medium is divided into a plurality of recording units, and second reading means for reading a third key encrypted with the second key recorded in the recording unit; The second key decrypted by the first decryption means,
A second decryption unit for decrypting the third key read by the second read unit; and a third key decrypted by the second decryption unit,
15. The information reproducing apparatus according to claim 14, further comprising third decoding means for decoding the data. 16. The information reproducing apparatus according to claim 14, wherein said storage means stores the secret key of one generation and generates the secret key of another generation by calculation. 17. The information reproducing apparatus according to claim 14, wherein the generation number of the first key corresponds to the generation of the secret key used in the generation unit. 18. An information reproducing method for an information reproducing apparatus for reproducing data recorded on a removable recording medium, comprising: a storage control step of controlling storage so as to store at least one or more generations of secret keys; A second key encrypted with the first key from the recording medium;
A first reading step of reading the generation number of the first key obtained by encrypting the second key, and medium identification information of the recording medium; and the medium read by the processing of the first reading step A generation step of generating the first key from the secret key corresponding to the identification information and the generation number; and a second step of decrypting the second key with the first key generated by the processing of the generation step. An information reproducing method, comprising: 19. A second reading step, wherein the recording medium is divided into a plurality of recording units, and a third key encrypted with the second key recorded in the recording unit is read. A second decryption step of decrypting the third key read by the processing of the second reading step with the second key decrypted by the processing of the first decryption step; 19. The information reproducing method according to claim 18, further comprising: a third decryption step of decrypting the data with the third key decrypted by the processing of the second decryption step. 20. The processing of the storage control step, wherein:
19. The information reproducing method according to claim 18, wherein the secret key of a generation is stored, and the secret key of another generation is generated by calculation. 21. The information reproducing method according to claim 18, wherein the generation number of the first key corresponds to the generation of the secret key used in the processing of the generation step. 22. A program for an information reproducing apparatus for reproducing data recorded on a removable recording medium, comprising: a storage control step of controlling storage so as to store at least one or more generations of secret keys. A second key encrypted with the first key from the recording medium;
A reading step of reading the generation number of the first key obtained by encrypting the second key, and medium identification information of the recording medium; and the medium identification information and the generation number read by the processing of the reading step. Generating the first key from the secret key corresponding to the following, and decrypting the second key with the first key generated by the processing of the generating step. A recording medium on which a computer readable program is recorded. 23. A recording medium on which data is recorded or reproduced by an information recording device or an information reproducing device, wherein: medium identification information which is a value unique to the recording medium; The second key used for encrypting the data, which is encrypted with a first key generated by a key, is recorded, and the second key encrypted with the first key is recorded. A recording medium, wherein the second key is recorded in association with the generation number of the first key.