JP2000122933A - System and method for ciphering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To disable deciphering even when an illegal copy is taken and to prevent a digital signal from illegally being copied by reading a digital signal after a 1st ciphering processing out of a recording medium and performing a 2nd ciphering processing for the read digital signal. SOLUTION: A flash memory 21 is stored with audio data obtained by performing the 1st ciphering processing for audio data recorded on a card type recording medium 20. In a redundancy area register 39, copyright flag as copyright information in redundant data is written and a ciphering part 30 is so controlled as to perform the 2nd ciphering processing once the setting of the copyright flag is detected. The ciphering part 40 performs the 2nd ciphering processing for the audio data from the memory 33. Thus, the double ciphering processings are performed for the digital signal to disable deciphering even when an illegal copy is taken and the digital signal recorded in a solid memory can be prevented from illegally being copied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an encryption system and an encryption method for performing an encryption process on a digital signal stored in a solid-state memory such as a flash memory.

[0002]

2. Description of the Related Art Today, there is a recording / reproducing system for recording audio data and video data in a solid-state memory such as a flash memory and reading and reproducing such data instead of an optical disk or a magnetic disk. In such a recording / reproducing system, by using a solid-state memory as a recording medium, the system can be downsized and the influence of vibration can be reduced.

As the recording / reproducing system, for example, a recording / reproducing system in which a recording medium is replaceable and which can reproduce audio data recorded on various recording media has been considered. In such a recording and reproducing system, it is convenient to carry each recording medium,
Further, since the storage capacity of the solid-state memory can be expected to be improved in the future, it is expected that the reproduction time can be lengthened.

[0004]

However, digital signals such as audio data and video data are easily copied from one device to another device, and have the property of not deteriorating no matter how many times they are copied. Therefore, in the case of a digital signal, there is a problem that exactly the same audio data and video data are generated by repeating dubbing.

For this reason, a recording / reproducing system for recording an encrypted digital signal on each recording medium has been proposed. However, even with such a recording / reproducing system, if a general-purpose encryption process is performed, if each device is provided with a decryption circuit for decrypting a digital signal corresponding to the encryption, the digital signal can be easily obtained. The signal is decoded, and illegal copying cannot be prevented.

SUMMARY OF THE INVENTION The present invention has been proposed in view of such circumstances, and it has been proposed that a digital signal recorded in a solid-state memory be protected from being decrypted even if an encrypted digital signal is illegally copied. It is an object of the present invention to provide an encryption system and an encryption method capable of preventing unauthorized copying of a document.

[0007]

In order to solve the above-mentioned problems, an encryption system according to the present invention comprises a recording medium comprising a solid-state memory on which a digital signal subjected to a first encryption process is recorded. Adapter means having encryption means for performing a second encryption process on a digital signal read from the recording medium, and transmission means for transmitting the digital signal subjected to the second encryption process by the encryption means And a control device for performing control for performing predetermined processing on the digital signal transmitted from the adapter means.

In the above-mentioned encryption system, the digital signal is subjected to the first and second encryption processes and transmitted to the control device.

The encryption method according to the present invention reads a digital signal from a recording medium composed of a solid-state memory on which a digital signal subjected to a first encryption process is recorded, and converts the read digital signal into a second signal. An encryption process is performed, the digital signal subjected to the second encryption process is transmitted, and a predetermined process is performed on the transmitted digital signal.

In the above-mentioned encryption method, the digital signal is subjected to the first and second encryption processes and transmitted to the control device.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

The present invention is applied to, for example, a recording / reproducing system 1 having the configuration shown in FIG. The above recording / reproducing system 1
Comprises a host computer 10 for controlling reading and writing of audio data, a card-type recording medium 20 for recording audio data, and a PC interface board 30.

The recording / reproducing system 1 can record audio data recorded on a host computer 10 on a card-type recording medium 20,
The audio data recorded in 0 is reproduced. In particular, the recording / reproducing system 1 reproduces the audio data without copying the audio data to the host computer 10 when the audio data whose copying is prohibited is recorded in the card type recording medium 20 in advance. Has become.

The host computer 10 corresponds to a so-called personal computer, and includes an I / O client 11 for transmitting and receiving control signals and the like to and from the PC interface board 30, an audio player 12 as software, a control program, and the like. (Read Only Memory) 13 in which is stored a CPU (Central Procedures) that controls each circuit according to the control program.
(single unit) 14 and a RAM (Random Access Memory) for temporarily storing data from the I / O client 11 and the like.
15 and a hard disk drive (hereinafter, referred to as “HDD”) 16 for storing data.

The I / O client 11 transmits a control signal indicating the operating state (status) of the host computer 10 and a serial clock SCLK for synchronization to the PC interface board 30 via the PC bus 17, and outputs audio data. And busy signal BSY etc. I / O
The data is received via the PC interface board 30.

The audio player 12 is started application software, and executes a process of reading and reproducing audio data from the card type recording medium 20 under the control of the CPU 14.

The HDD 16 stores audio data read from the card-type recording medium 20 via the PC interface board 30 or reads recorded audio data under the control of the CPU 14, for example.

The card type recording medium 20 includes a flash memory 21 for recording audio data and the like, and a memory controller 22 for reading out audio data recorded in the flash memory 21.

Here, the flash memory 21
It is composed of four blocks. One block is composed of 16 pages, and one page is composed of 528 bytes. In one page, audio data is recorded in a 512-byte normal area, and redundant data such as a copyright flag is recorded in a 16-byte redundant area. Therefore, the storage capacity of the flash memory 21 is about 8 Mbytes ($ 5
28 × 16 × 1024 bytes).

The memory controller 22 writes audio data to the flash memory 21 in page units,
Deletes audio data written in block units.

The PC interface board 30 is an interface between the host computer 10 and the card type recording medium 20 and may be provided inside the host computer 10 or may be provided inside the card type recording medium 20. Is also good.

The PC interface board 30 includes:
A PCMCIA card (conforming to the JEIDA / PCMCIA standard) adapter is used, and a serial protocol control unit 31 and a PC interface control unit 32
A memory 33 for storing audio data for each page, a decoder 34 for decoding the audio data in the memory 33, a D / A converter 35 for converting the audio data decoded by the decoder 34 into an analog signal, Amplifier 36 that amplifies and outputs the audio signal
And

The serial protocol control unit 31 reads audio data and data in a redundant area from the card type recording medium 20 based on a serial protocol control signal from the PC interface control unit 32 and stores the audio data in the memory 33 in the redundant mode. The copyright flag of the data is supplied to the PC interface control unit 32.

The PC interface control unit 32 performs a pulse code modulation on the audio data as necessary.
M (Pulse Code Modulation) circuit 37 and I / O for transmitting audio data and the like and receiving a predetermined command
A register 38 and a redundant area register 39 to which a copyright flag which is data of a redundant area is supplied.

The PCM circuit 37 is a circuit used when audio data is degraded, and performs a PCM modulation process on the audio data supplied from the memory 33.
The audio data is supplied to the I / O register 38. Note that the PCM circuit 37 converts the audio data into I / O data as it is when there is no need to degrade normal voice.
Supply to register 38.

The I / O register 38 receives audio data from the PCM circuit 37, a ready signal RDY and a busy signal BSY via the PC bus 17 at a predetermined timing.
O Transmit to the client 11.

The redundant area register 39 detects whether the copyright flag in the redundant data is set. Specifically, when detecting that the copyright flag is set, the redundant area register 39 disables the I / O register 38 and stops the output of the audio data. Also, the redundant area register 39
When the copyright flag is not set, the redundant data from the redundant area register 39 is transmitted to the
/ O Client 11

At the time of recording, the recording / reproducing system 1
Transmission and reception of control signals and audio data are performed according to the time chart shown in FIG. Specifically, as shown in FIG. 2A, the I / O client 11 inverts and outputs a control signal indicating an operation state (status) at a predetermined timing to change the status. Each time the control signal BS is inverted, the operation state is changed to the status BS0, BS1, BS2, B
The status changes to S3, and then the status changes to BS0 again. That is, the four statuses are repeatedly changing. When the status is BS1 or BS2, the host computer 10 performs a predetermined operation, and the status BS0 or BS2.
In the case of 3, the PC interface board 30 (or the card type recording medium 20) performs a predetermined operation.

When the status is BS0, both the I / O client 11 and the I / O register 38 are in an idling state and do not output any data. I / O client 11
Starts transmission of a TPC (transfer protocol command) signal, the status becomes BS1.

In the status BS 1, the I / O client 11 sends the I / O register 38 via the PC bus 17.
2B, a TPC (transfer protocol command) signal for writing data is transmitted as shown in FIG. 2B, and a serial clock SCLK is transmitted as shown in FIG. 2C. When the transmission of the TPC signal ends, the status becomes BS2.

In the status BS2, the I / O client 11 sends an I / O register
The audio data read from 16 is transmitted, and then a CRC signal, which is a code for performing error correction, is transmitted. Then, audio data is recorded in the flash memory 21 of the card type recording medium 20 via the PC interface board 30. When the transmission of the CRC signal ends, the status becomes BS3.

In the status BS3, the I / O register 3
8 transmits to the I / O client 11 a busy signal BSY indicating that the flash memory 21 is recording audio data, and upon completion of the recording, a ready signal indicating that preparation for receiving the next command is completed. Signal R
Send DY. Then, when the transmission of the ready signal RDY ends, the status becomes the status 0 again.

After the above processing, the host computer 1
From 0, the recording process of the audio data on the card-type recording medium 20 ends.

When reproducing the audio data recorded in the flash memory 21, the recording / reproducing system 1 performs different reproduction processing depending on whether a copyright flag is added to the audio data. In the case of reproduction, as in the case of recording, as shown in FIG.
There are three statuses BS0, BS1, BS2, BS3. When the status is BS1, the host computer 10 performs a predetermined operation, and the status BS0, BS
2, PC interface board 30 for BS3
(Or the card type recording medium 20) performs a predetermined operation.

When the copyright flag is not set and the status is BS0, the I / O client 1
1 and the I / O register 38 are in an idling state and do not output any data. I / O client 11 is TPC
When the transmission of the signal is started, the status becomes BS1.

In the status BS 1, the I / O client 11 sends the I / O register 38 via the PC bus 17.
In response to this, a TPC signal for reading data is transmitted as shown in FIG. 3B, and a serial clock SCLK is transmitted as shown in FIG. 3C. TPC
When the transmission of the signal is completed, the status becomes BS2.

In the status BS2, the I / O register 3
8 transmits to the I / O client 11 a busy signal BSY indicating that preparation for reading audio data from the flash memory 21 is being performed, and when the preparation is completed, a ready signal indicating that it is ready for reading is prepared. Transmit the signal RDY. When the transmission of the ready signal RDY is completed, the status becomes BS3.

In the status BS3, the I / O register 3
Reference numeral 8 denotes a serial protocol control unit 31 and a memory 3 from the flash memory 21 to the I / O client 11.
Then, the audio data to be read out is transmitted via the H.3, and after the data transmission, the CRC signal is also transmitted. In the host computer 10, the audio data transmitted from the I / O register 38 is temporarily stored in the RAM 15, and thereafter,
The audio data is stored in the HDD 16. When the transmission of the CRC signal ends, the status B is returned again.
Return to S0.

On the other hand, when the copyright flag is set, similarly to the case where the copyright flag is not set, the status B is passed through the statuses BS0, BS1, and BS2.
Move to S3.

In the status BS3, the serial protocol control section 31 supplies audio data from the card type recording medium 20 to the memory 33 and supplies redundant data to the PC interface control section 32. When detecting the copyright flag, the redundant area register 39 controls the I / O register 38 not to transmit audio data to the host computer 10. As a result, it is possible to prevent the audio data recorded on the card type recording medium 20 from being copied to the host computer 10.

On the other hand, the decoder 34 reads out and decodes the audio data stored in the memory 33 and supplies it to the amplifier 36 via the D / A converter 35.
Then, the amplifier 36 amplifies the audio signal and outputs sound to the outside.

As described above, the recording / reproducing system 1
Prevents the audio data with the copyright flag set from being copied from the card-type recording medium 20 to the host computer 10, while obtaining an analog reproduction output of the audio data.

The host computer 10 displays "copyright data cannot be read" on a monitor (not shown) when the PC interface board 30 notifies that the copyright flag is set. Is also good. Thus, the user can be notified that the audio data is protected by the copyright.

The recording / reproducing system 1 not only outputs the audio data in analog form via the decoder 34, the amplifier 36 and the like, but also copies the audio data from the card type recording medium 20 to the host computer 10. The sound quality of data can be degraded.

More specifically, the PCM circuit 37 stores the memory 3
3 performs PCM modulation on the audio data from I / O
Supply to register 38. At this time, even when the copyright flag is detected, the redundant area register 39 does not control the I / O register 38 not to transmit data. Therefore, the I / O register 38 transmits the audio data to the I / O client 11 of the host computer 10. Thus, the host computer 1
The audio data transmitted to 0 is temporarily stored in the RAM 15 and then recorded on the HDD 16.

As described above, when the audio data is copied to the host computer 10, the recording / reproducing system 1 performs the process of deteriorating the sound quality. Copying can be prevented.

Next, a second embodiment of the present invention will be described. Note that the same circuits as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted.

In the second embodiment of the present invention, for example, the present invention is applied to a recording / reproducing system 1A having a configuration shown in FIG. The recording / reproducing system 1A includes a host computer 1 for controlling reading and writing of audio data.
0A, a card-type recording medium 20 for recording audio data, and a PC interface board 30A.

The host computer 10A includes a first encryption process (Ks1) and a second encryption process (Ks1) in addition to the configuration of the host computer 10 in the first embodiment.
2) A decoding unit 18 for decoding already processed audio data is provided.

Here, the first encryption process is an encryption process performed on audio data recorded on the card type recording medium 20. On the other hand, the first decryption processing refers to decrypting the data that has been subjected to the first encryption processing. The second encryption process refers to an encryption process performed by the encryption unit 40 described later in detail. The second decryption processing refers to decrypting the data that has been subjected to the second encryption processing. The processing of the second encryption processing is different depending on each recording / reproducing system. Therefore, the second decryption process also has different contents depending on each recording / reproducing system.

The card type recording medium 20 includes a flash memory 21 for recording audio data, and a memory controller 22 for controlling reading of audio data recorded in the flash memory 21 and the like. The flash memory 21 records audio data that has been subjected to the first encryption processing.

The PC interface board 30A includes a serial protocol controller 31 for reading audio data and redundant data read from the card type recording medium 20.
And a PC interface control unit 32A for transmitting and receiving data to and from the host computer 10, and a memory 33 for storing audio data from the PC interface control unit 32A.

The serial protocol control unit 31 reads audio data and data in a redundant area from the card type recording medium 20 based on the serial protocol control signal from the PC interface control unit 32A, and stores the audio data in the memory 33 in the redundant mode. The copyright flag of the data is supplied to the PC interface control unit 32A.

The PC interface control unit 32A includes a redundant area register 39 to which a copyright flag, which is data of a redundant area, is supplied, an encryption unit 40 for performing a second encryption process on audio data from the memory 33, I / O
A host I / F register 41 for transmitting and receiving I / O data to and from the client 11 is provided.

As shown in FIG. 5, a copyright flag, which is copyright information in the redundant data, is written into the redundant area register 39. When the copyright flag is set, the second encryption processing is performed. The encryption unit 40 is controlled to perform the following. When the copyright flag is not set, the redundant area register 39 does not cause the encryption unit 40 to perform the second encryption processing.

As shown in FIG. 6, an encryption key is written in the encryption unit 40. The host I / F register 40
Under the control of the redundant area register 39, the second encryption process is performed on the audio data read from the memory 33 for each page. The encryption process performed here is
This is performed using a random function in one page cycle for audio data in units of one page. In this case, the encryption key is also written for each page in the redundant area. Note that the unit of such encryption processing is not limited to one page unit, and may be, for example, one block unit or one file unit. The encryption unit 40
The audio data encrypted as described above is supplied to the host I / F register 41.

As shown in FIG. 7, the host I / F register 41 has a lower data register (Lower Data Register).
r) and the Upper Data Registe
r) and the control register (Control Data Registe
r), a command register (Command Register), and a status register (Status Register).

The host I / F register 41 analyzes the command and status BS transmitted from the I / O client 11 using these registers, and performs processing according to the analysis result.

The host I / F register 41 transmits the audio data supplied from the encryption unit 40 to the I / O client 11 under the control of the redundant area register 39.
Send to In this way, the first and second encrypted audio data are transmitted to the host computer 10.

In the host computer 10, the CP
The U 14 temporarily stores the audio data transmitted from the PC interface board 30 in the RAM 15, and then writes the audio data in the HDD 16. When reproducing the audio data, the CPU 14 reads the audio data from the HDD 16 and causes the decoding unit 18 to perform the first and second decoding processes.
2 performs a reproduction process.

As described above, the recording / reproducing system 1
The first and second encrypted audio data are stored in the C interface board 30 by the host computer 10.
, It is possible to prevent the reproduction of the audio data even when the audio data is copied from the host computer 10 to another computer.

That is, when the other computer reproduces the copied audio data, it must perform the first and second decoding processes on the audio data. However, the other computer does not include the decoding unit 18 that performs the same second decoding process as the host computer 10A, and thus cannot perform the second decoding process. Therefore, even if the audio data recorded on the HDD 16 is copied to another recording medium,
The audio data cannot be reproduced, and as a result, the reproduction of the illegally copied audio data can be prevented.

In the above-described embodiment, the case where the first and second encrypted audio data are transmitted to the host computer 10 has been described. However, the audio data is decrypted after the first encryption processing is decrypted. Host computer 1
It may be transmitted to 0A.

Specifically, the serial protocol control unit 3
1 decrypts the first encrypted audio data read from the card type recording medium 20 and stores the decrypted audio data in the memory 3
3 may be supplied to the PC interface control unit 32A. Then, the audio data subjected to only the second encryption processing is transmitted to the host computer 10A. This allows the host computer 10A to perform only the second decoding process when using the audio data, and thus can reduce the processing load in the decoding process.

In the present embodiment, audio data has been described as an example, but the present invention is not limited to this, and it is needless to say that video data can be similarly applied. is there.

Although the flash memory has been described as an example of the solid-state memory, it is needless to say that the present invention can be applied to a semiconductor memory such as a nonvolatile RAM.

Further, instead of the HDD 16 in the host computer 10, an optical disk drive for recording and reproducing data on an optical disk and a flexible disk drive for recording and reproducing data on a flexible disk may be used.

[0068]

As described above in detail, according to the encryption system and the encryption method of the present invention, a recording medium comprising a solid-state memory in which a digital signal subjected to the first encryption processing is recorded. , A second encryption process is performed on the read digital signal and the digital signal is transmitted, so that the digital signal is subjected to a double encryption process and cannot be decrypted even if the digital signal is illegally copied. As a result, illegal copying of the digital signal recorded in the solid-state memory can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a recording / reproducing system to which the present invention is applied.

FIG. 2 is a time chart for explaining the recording operation of the recording / reproducing system.

FIG. 3 is a time chart for explaining an operation at the time of reproduction of the recording / reproducing system.

FIG. 4 is a block diagram illustrating a configuration of a recording / reproducing system according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a flash memory provided in a recording medium of the recording / reproducing system.

FIG. 6 is a diagram illustrating a state in which an encryption key is written in an encryption unit of a PC interface board in the recording / reproducing system.

FIG. 7 shows the host interface of the PC interface board.
FIG. 3 is a diagram illustrating a configuration of an F register.

[Explanation of symbols]

1 recording and playback system, 10 host computer, 1
4 CPU, 16 HDD, 20 card type recording medium,
21 flash memory, 30 PC interface board, 31 serial protocol control unit, 32, 32
A PC interface control unit, 34 decoder, 3
6 amplifier, 37 PCM circuit

Continued on the front page F term (reference) 5B017 AA06 BA07 BB08 CA12 CA16 5C053 FA13 FA23 FA27 JA01 KA05 KA24 LA11 LA14 5C064 CA16 CA18 CB05 5J104 AA13 NA35 PA07 PA14

Claims (7)

[Claims] 1. A recording medium comprising a solid-state memory on which a digital signal subjected to a first encryption process is recorded, and an encryption means for performing a second encryption process on a digital signal read from the recording medium. , The second encryption means
An encryption system comprising: an adapter having transmission means for transmitting a digital signal subjected to the encryption processing; and a control device for performing control for performing predetermined processing on the digital signal transmitted from the adapter. 2. The encryption system according to claim 1, wherein the control device includes a recording unit that records the digital signal transmitted from the adapter unit. 3. The encryption system according to claim 1, wherein said adapter means includes an encryption key for performing said second encryption processing. 4. The apparatus according to claim 1, wherein said adapter means includes first decryption means for decrypting the first encrypted digital signal recorded on said recording medium.
The described encryption system. 5. A digital signal is read from a recording medium comprising a solid-state memory on which the digital signal subjected to the first encryption processing is recorded, and the read digital signal is subjected to a second encryption processing. An encryption method, comprising: transmitting a digital signal subjected to a second encryption process; and subjecting the transmitted digital signal to a predetermined process. 6. The encryption method according to claim 4, wherein said predetermined processing stores a transmitted digital signal. 7. The digital signal according to claim 1, wherein the read digital signal subjected to the first encryption processing is decrypted.
The encryption method described.