JP2006135815A - Error detection encoding circuit, data recorder having the error detection encoding circuit and data recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an error detection encoding circuit capable of preventing wrong data from being outputted and wrong data record processing based on this output, a data recorder having the error detection encoding circuit and a data recording method. <P>SOLUTION: A storing part stores error detection encoded data, when the data stored in the storing part are sequentially read and outputted, the data stored in the storing part are encrypted by using an encryption key, the encrypted data are stored in the storing part, the encrypted data read from the storing part are decrypted by using the encryption key, the correctness of the data is determined on the basis of the decrypted data, and the decrypted data are outputted when the data are correct. The encryption key is configured by using unused bits in the data to be encrypted. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an error detection encoding circuit, a data recording apparatus having the error detection encoding circuit, and a data recording method.

  Conventionally, when data is recorded on a recording medium such as an optical disk, the error detection encoded data such as a CIRC (Cross Interleaved Reed-Solomon Code) encoder is used to record the data. The reproduced data can be accurately reproduced (see, for example, Patent Document 1).

In such an error detection encoding means such as a CIRC encoder, the error detection encoded data is temporarily stored in a storage unit configured by SRAM (Static Random Access Memory) or the like, and the error detection encoded data is stored from this storage unit. Are sequentially read and written to the recording medium by the data writing means.
JP 2003-243993 A

  However, when the data stored in the storage unit of the error detection encoding unit is read and the data is written to the recording medium as described above, data at an incorrect address in the storage unit may be read out. There is a risk that the writing process to the recording medium may be performed based on erroneous data.

  In particular, reading of data at such an incorrect address often occurs at the start of the data writing process to the recording medium, and if it occurs during the data writing process called frame information, If incorrect frame information is written, there is a possibility that correct reproduction of data from the recording medium cannot be performed.

  The error detection encoding circuit of the present invention is an error detection encoding circuit that performs error detection encoding on data to be recorded on a recording medium, and stores the error detection encoded data in a storage unit. In an error detection encoding circuit that sequentially reads and outputs data, an encryption unit that encrypts data stored in the storage unit using an encryption key and stores the encrypted data in the storage unit; Decrypts the encrypted data read from the unit using the encryption key, determines the validity of the data based on the decrypted data, and outputs the decrypted data if it is valid It has decided to have the decoding part which performs.

  Furthermore, the encryption key is also characterized in that it is configured using unused bits in the data to be encrypted.

  The data recording apparatus of the present invention stores the error detection encoded data in the storage unit, and sequentially reads out and outputs the data from the storage unit, and outputs from the error detection encoding unit. In a data recording apparatus having a recording means for recording the recorded data on a recording medium, the error detection encoding means encrypts the data stored in the storage unit by using an encryption key, and converts the encrypted data into The encryption unit to be stored in the storage unit, and the encrypted data read from the storage unit are decrypted using the encryption key, and the validity of the data is determined based on the decrypted data. In this case, a decoding unit that outputs the decoded data is provided.

  Furthermore, the encryption key is also characterized in that it is configured using unused bits in the data to be encrypted.

  Further, in the data recording method of the present invention, in the data recording method in which the data subjected to the error detection encoding by the error detection encoding means is stored in the storage unit, and the data is read from the storage unit and recorded on the recording medium. The encrypted data generated by encrypting with the encryption key is stored in the storage unit, and the encrypted data read from the storage unit is decrypted using the encryption key, and the data is based on the decrypted data. It is decided that the decrypted data is recorded on the recording medium if it is valid.

  Furthermore, the encryption key is also characterized by being configured using unused bits in the data.

  In the present invention, error detection encoding means comprising an error detection encoding circuit that generates and outputs error detection encoded data, the error detection encoded data is temporarily stored in a storage unit, and then sequentially output In this case, the storage unit stores the error detection encoded data that is encrypted with the encryption key, and uses the encrypted data read from the storage unit for encryption. The data is decrypted and the decrypted data is output. Especially, the legitimacy of the data is judged based on the decrypted data, and the decrypted data is output if it is valid. Thus, it is possible to provide a means for determining the validity of the data output from the error detection encoding means.

  Therefore, when there is an abnormality in the decoded data, the output of erroneous data can be suppressed by not outputting the data, and the occurrence of malfunction can be suppressed.

  In particular, when the required data is written on the recording medium, the abnormality detected by the above-described determination means occurs in a so-called frame information portion, so that writing control by misinterpretation based on erroneous frame information is performed. Malfunctions such as circuits can be suppressed.

  Further, since the encryption key is configured using the unused bits in the data to be encrypted, the validity of the data decrypted easily in the unused bit portion can be determined. It is possible to prevent the increase in cost by simplifying the configuration.

  In the error detection coding circuit of the present invention, the data recording apparatus having the error detection coding circuit, and the data recording method, the error detection coded data is stored in the storage unit, and the data is sequentially read from the storage unit. The data stored in the storage unit is encrypted using the encryption key, and when the encrypted data is read from the storage unit, it is decrypted by the encryption key used for encryption. To output the decrypted data.

  In particular, data that has been correctly read from the storage unit to output data can be correctly reproduced with the decryption using the encryption key, while the data stored in the storage unit is erroneous. When data is read, the data before encryption cannot be correctly reproduced along with decryption using the encryption key, and it is detected that illegal data is read. By prohibiting the output of invalid data, only valid data can be output.

  In particular, the encryption key is configured using unused bits in the data to be encrypted. In the following, a method for determining the validity of data encrypted using this encryption key and the encryption key in this embodiment will be described in detail.

  Here, it is assumed that the data stored in the storage unit constitutes one data with a required number of bits such as 4 bits, 8 bits, and 16 bits. In the following, for convenience of explanation, it is assumed that the data is 8 bits.

  In this way, in the data composed of 8 bits, any one of the bits may not be used as a data bit for holding required data. Such bits that are not used as data bits are called unused bits. Here, it is assumed that “0” is stored in the unused bits.

  The encryption key is configured using these unused bits. For example, as shown in FIG. 1, in 8-bit data, the first bit from the right (hereinafter referred to as “first bit”), When the third bit from the right (hereinafter referred to as “third bit”) is an unused bit, there are four encryption keys: “00000000”, “00000001”, “00000100”, and “00000101”. . Note that “0” is stored in bits other than unused bits, but “1” may be stored.

  Here, the encryption key has the same 8 bits as the data, but for the convenience of encryption and decryption, it has the same number of bits as the data. In some cases, it is necessary to match the number of bits of the data. For example, the encryption key may be composed of 2 bits of the first bit and the third bit.

  In the following, it is assumed that “00000100” is adopted as the encryption key, as shown in FIG. At this time, as shown in FIG. 1A, when the data “01100010” error-encoded and encoded is stored in the storage unit using the encryption key, the exclusive OR of the data and the encryption key is stored. The encrypted data “01100110” generated from is stored in the storage unit.

  When the encrypted data is correctly read from the storage unit, the read encrypted data “01100110” and the previous encryption key “00000100” are decrypted by exclusive OR. Decrypted data “01100010” is generated.

  The decrypted data and the data before encryption are both “01100010”, and it can be seen that correct data is read from the storage unit. In particular, the first and third bits, which are unused bits, are “0”.

  On the other hand, as shown in FIG. 1B, for example, “01010010” is read as erroneous data from the storage unit, and the data encrypted with the encryption key “00000100” is read. In this case, when the erroneous data is decrypted with the encryption key “00000100”, it becomes “010110110”, and in particular, the third bit among the unused bits is “1”.

  In this way, the unused bit portion is always used as “0” when encryption and decryption are performed using the same encryption key. By detecting “1”, it can be determined that illegal data has been read.

  On the other hand, when all the unused bit portions are “0” after decryption, the decrypted data is output as legitimately read data.

  In this way, by using data encryption and decryption using the encryption key, it is possible to construct a determination means for determining the validity of the data read from the storage unit.

  Moreover, by configuring the encryption key using unused bits of data, it is possible to determine the validity of the decrypted data very easily, simplifying the configuration of the determination means and increasing the cost. Can be prevented.

  Finally, as described above, a data recording apparatus having an error detection encoding circuit that writes data to the storage unit and reads data from the storage unit while performing encryption and decryption using an encryption key. explain. Here, the data recording apparatus performs data writing to an optical disc that is writable, and the error detection encoding means is constituted by a CIRC encoder.

  As shown in FIG. 2, the data recording apparatus A according to the present embodiment includes a data storage unit 30 such as a hard disk that stores data to be written on the optical disc 11, and data read from the data storage unit 30 on a recording medium. An encoder unit 20 that encodes data in a data format adapted to the optical disc 11 and a data writing unit 10 as a recording unit that writes and records the data encoded by the encoder unit 20 on the optical disc 11 are configured. .

  The data writing unit 10 is provided with a laser diode 12 for outputting a laser used for writing data to the optical disc 11, a control driver circuit 13 for controlling the laser diode 12, and the like. Based on the data, the control driver circuit 13 controls the output of the laser diode 12 to write the required data.

  The encoder unit 20 appropriately encodes and outputs the data input from the data storage unit 30. In particular, in the present embodiment, the CIRC encoder 21 serving as error detection encoding means is provided to perform CIRC encoding. The data is being output.

  The CIRC encoder 21 includes a CIRC data control circuit 22 that performs CIRC encoding of input data, a storage unit 23 that includes an SRAM that temporarily stores the CIRC data generated by the CIRC data control circuit 22, and the storage unit The ERC data control circuit 24 is configured to read out the CIRC data stored in 23, perform EFM (Eight to Fourteen Modulation) processing, and output it.

  In particular, an interface circuit 25 is provided between the CIRC data control circuit 22 and the EFM data control circuit 24 and the storage unit 23, and data is input from the CIRC data control circuit 22 to the storage unit 23 via the interface circuit 25. The data is output from the storage unit 23 to the EFM data control circuit 24. Further, a parity adding circuit 26 is connected to the interface circuit 25 so that the interface circuit 25 can perform desired encoding.

  As shown in FIG. 3, the interface circuit 25 includes an encryption key generation unit 25a serving as an encryption key generation unit for generating an encryption key, and an encryption key generated by the encryption key generation unit 25a. An encryption unit 25b that encrypts data input from the CIRC data control circuit 22, and a decryption unit 25c that decrypts data read from the storage unit 23 based on the encryption key generated by the encryption key generation unit 25a And are provided.

  In the encryption key generation unit 25a, as shown in FIG. 4, a counter unit 25a-1 that counts based on the input of an encoding start signal, an end signal, or an interruption signal, and the count result in the counter unit 25a-1 The decoding unit 25a-2 for decoding the data, and the encryption key data generated by the decoding unit 25a-2 are assigned to the unused bit positions, and “0” is assigned to the bit portion other than the unused bits to assign the encryption key. The synthesizing unit 25a-3 is configured to synthesize the encryption key from the synthesizing unit 25a-3.

  The encryption unit 25b is an encryption circuit that generates encrypted data by performing an exclusive OR of the data input from the CIRC data control circuit 22 and the encryption key input from the encryption key generation unit 25a. The encrypted data generated by exclusive OR is stored in the storage unit 23.

In particular, when storing the encrypted data in the storage unit 23, for example, for the data input from the k-th CIRC data control circuit 22, the k-th encryption generated by the encryption key generation unit 25a is used. Encrypted data is generated using the encryption key and stored in the k-th k-th storage area 23 _k in the storage unit 23. Here, k is a natural number.

  That is, encrypted data is generated using a different encryption key generated by the encryption key generation unit 25 a for each data to be stored in the storage unit 23 and stored in a predetermined storage area of the storage unit 23.

  The decryption unit 25c reads the encrypted data stored in the predetermined storage area of the storage unit 23, and performs an exclusive OR operation between the read encrypted data and the encryption key generated by the encryption key generation unit 25a. And a decryption circuit that performs decryption and outputs the decrypted data to the EFM data control circuit 24.

In particular, when the encrypted data stored in the k-th k-th storage area 23 _k in the storage unit 23 is read, it is decrypted using the k-th encryption key generated by the encryption key generation unit 25a. In addition, by using different encryption keys between adjacent data, it is possible to reliably detect that erroneous data has been read when the adjacent data is erroneously read.

  The EFM data control circuit 24 checks the value of the unused bit portion of the combined data, and if the values of the unused bits are all “0”, the combined data is valid data. A determination circuit for determining is provided, and when it is determined that the combined data is valid data, the combined data is output.

  On the other hand, when “1” is present in the unused bit of the decoded data, the decoded data is not valid data. When this data is frame information, EFM data is used. This data is invalidated by the determination circuit in the control circuit 24.

  In this way, the validity of the data read from the storage unit 23 can be determined very easily by using the encryption and decryption using the encryption key.

  In the above-described embodiment, the case where CIRC encoding is performed using the optical disc 11 as the recording medium has been described. However, the present invention is not limited to the CIRC encoding, but can be applied to a DVD (Digital Versatile Disc) encoder. It can be easily applied to what is performed.

It is explanatory drawing explaining the encryption and decryption by an encryption key. 1 is a schematic explanatory diagram of a data recording apparatus according to the present invention. It is a schematic explanatory drawing of the error detection encoding circuit based on this invention. It is explanatory drawing of an encryption key production | generation part.

Explanation of symbols

A Data recording device
10 Data writing part
11 Optical disc
12 Laser diode
13 Control driver circuit
20 Encoder section
21 CIRC encoder
22 CIRC data control circuit
23 Memory
24 EFM data control circuit
25 Interface circuit
25a Encryption key generator
25b Encryption part
25c Decryption unit
26 Parity addition circuit
30 Data storage

Claims (6)

An error detection encoding circuit for performing error detection encoding on data to be recorded on a recording medium, storing the error detection encoded data in a storage unit, and sequentially reading and outputting the data from the storage unit In the encoding circuit,
An encryption unit that encrypts data stored in the storage unit using an encryption key and stores the encrypted data in the storage unit;
The encrypted data read from the storage unit is decrypted using the encryption key, and the validity of the data is determined based on the decrypted data. An error detection encoding circuit comprising: a decoding unit that outputs converted data.   2. The error detection encoding circuit according to claim 1, wherein the encryption key is configured using unused bits in the encrypted data. The error detection encoded data is stored in the storage unit, and the error detection encoding unit that sequentially reads and outputs the data from the storage unit, and the data output from the error detection encoding unit is recorded on the recording medium. In a data recording apparatus having recording means for
The error detection encoding means includes
An encryption unit that encrypts data stored in the storage unit using an encryption key and stores the encrypted data in the storage unit;
The encrypted data read from the storage unit is decrypted using the encryption key, and the validity of the data is determined based on the decrypted data. A data recording apparatus comprising: a decoding unit that outputs converted data.   4. The data recording apparatus according to claim 3, wherein the encryption key is configured using unused bits in the encrypted data. In the data recording method of storing the data subjected to error detection encoding by the error detection encoding means in the storage unit, and reading the data from the storage unit and recording it on the recording medium
Encrypted data generated by encrypting the data with an encryption key is stored in the storage unit, and the encrypted data read from the storage unit is decrypted using the encryption key and decrypted. A data recording method comprising: determining validity of data based on the data; and recording the decrypted data on the recording medium when the data is valid.   6. The data recording method according to claim 5, wherein the encryption key is configured using unused bits in the data.

Images