JPH10320292A - Information recording and reproducing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate trouble for inputting a password number by automatically preparing encipher and decipher keys from format information previously recorded in an information record medium. SOLUTION: When an optical card is inserted, the format information is reproduced (S102). In this case, the encipher and decipher keys required for enciphering and deciphering at the time of recording and reproducing data are prepared (S103). Data sent together with a recording command are enciphered by the encipher key prepared (S103) from the format information (S117). When a command is a reproducing command, a sector address to be reproduced is found and data are reproduced (S121). Since data reproduced in this case are enciphered data, they are deciphered by using the decipher key prepared (S103) from the format information (S122), the deciphered data are transferred to a host computer, and reproducing processing is finished.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical card information recording / reproducing system having an encryption means for encrypting data to be recorded and a decryption means for decrypting the encrypted data.

[0002]

2. Description of the Related Art Conventionally, information is recorded using light,
As a form of a recording medium from which recorded information is read, various forms such as a disk, a card, and a tape are known. Among these, in particular, an optical information recording medium formed in a card shape (hereinafter referred to as an “optical card”)
It has a recording capacity of several thousand to 10,000 times that of a magnetic card and cannot be rewritten like an optical disc, but its recording capacity is as large as 1 to 6 Mbytes. A wide range of applications, such as a business map or a prepaid card used for shopping, is considered as an object to be used.

When recording and reproducing data on such an optical card, usually, a directory for managing the data is recorded on a part of the optical card together with the data, and the data is stored for each file. Is generally managed. The directory is a file name, as shown in FIG.
Information necessary for file management, such as the start address of the first data and the number of consecutively recorded sectors. Each time data is recorded, this directory is recorded in a part of the recording area of the optical card as management information of the data.

FIG. 5 is a schematic plan view showing an optical card.
1 is an optical card and 2 is an information recording area. In the information recording area 2, tracking tracks 3 _{1 to} 3 _{n + 1} are arranged in parallel at regular intervals, and information tracks 4 ₁ for recording information between the respective tracking tracks.
４4 _n are provided. At each end of each information track,
Physical track number 5 for identifying the information track
_{1 to} 5 _n are added in advance.

[0005] In the optical card in Fig. 5, block 6 ₁ information track 4 ₂ to 4 _k, the information track 4 _k + ₁ ~4 _n-1 as the block 6 _2, the information recording region 2 into two blocks Has been split. The division of the optical card 1 into a plurality of blocks is described in JP-A-63-244385.
No., published in Japanese Unexamined Patent Publication No.

For example, an optical card is used for recording medical information.
It is used as a medium and the patient's ECG information and blood pressure information
Block 6 when recording information₁ECG information
Lock 6_TwoCan record blood pressure information. This
Divided into blocks for each type of data to be recorded.
Block 6 when playing back ECG information ₁
Access time because only the data in the
Can be shortened. Of course, the number of divided blocks
And the number of information tracks in a block indicate the type of data to be recorded.
It can be set arbitrarily according to the type and the data amount.

In the optical card 1, a method has been devised in which the number of sectors and the sector size of one information track are changed for each block. FIG. 6 shows an example of the relationship between the sector size of data to be recorded on one information track and the number of sectors. In FIG. 6, the sector type 1 has one 1024-byte sector and the information track 4
The sector type 2 records two 512-byte sectors on the information track 4 and the sector type 3 records
Four 56-byte sectors are recorded on the information track 4,
Sector type 4 records six 128-byte sectors on the information track 4, sector type 5 records eight 64-byte sectors on the information track 4, and sector type 6 records a 32-byte sector. This indicates that 12 sectors are recorded on the information track 4.

In this method, for example, when 768-byte data is recorded in sector type 1, only one sector (one information track) needs to be recorded. Sector (information track 2
Book). Therefore, when recording is performed in the sector type 6, not only takes time but also wastes the recording capacity of the optical card.

When 32 bytes of data are recorded in sector type 1, one information track is used. However, when data is recorded in sector type 6, only one sector is required. Only 1/12 information tracks are used. Thus, by selecting the sector type according to the data size to be recorded, not only can the access speed be increased, but also the recording area of the optical card can be used effectively.

[0010] Here, in FIG. 5, 7 ₁₁ to _7-1i is a data recorded in the block 61, 7 ₂₁
.About.7 _2j are data recorded in the block 62. Also, 8 ₁₁ to 8 _1i is a directory for managing data 7 ₁ recorded in the block 61, 8
₂₁ to 8 _2j is data recorded in the block 62 7 ₂
Is a directory for managing. Data is additionally written in the B direction, and the directory is additionally written in the F direction.

As described above, when medical information is recorded on the optical card, the electrocardiogram information may be recorded as data 7 ₁ , its management information as directory 8 ₁ , blood pressure information as 7 ₂ , and its management information as 8 _2. . When recording information having a large data amount, such as electrocardiogram information, the data 7 _{11 to} 7 _1i
When the sector size is increased and the number of sectors to be recorded on one information track is reduced to one as described above, the access speed can be increased. Conversely, as the blood pressure information, if the data amount is small, a smaller sector size as data 7 ₂₁ to _7-2j, if increasing the number of sectors to be recorded on one information track, the optical card recording The capacity can be used effectively. The data size of the directory is
Since the size is relatively small, it is preferable to record the data with the sector size 5, for example.

Further, in any of the block information tracks 4 ₁ and the information track that does not belong to 4 _n of the optical card, the block division number of the optical card 1 described above, the track number of each block, the sector type used in each block Optical card management information 9 (hereinafter, referred to as “format information”) is recorded.

FIG. 7 is a diagram showing the contents of the format information. The first identification information is information for identifying the format information. For example, information such as "FMT" in ASCII code is entered. The next block division number is information indicating how many blocks the optical card 1 is divided into. Then, information indicating the respective number of information tracks and sector type of blocks ₆₁ through block 6 _n enters.

Incidentally, recording and reproduction of information on the optical card can be performed by any user. for that reason,
When used by a large number of users, there is a possibility that necessary information is erroneously destroyed, information is falsified intentionally, or highly confidential information can be seen by others.

Therefore, personal information (hereinafter referred to as "password information") is recorded for each block of the optical card, and when data is recorded or reproduced in the block where the password information is recorded, a password is used. A method of inputting information, collating the inputted password information with the password information recorded in the block, and permitting the recording and reproduction of the information in the block only when the collation result matches, is adopted. I have.

[0016] 10 ₁₁ 10 ₁₂ in FIG. 5 is a password information block _61. As shown in FIG. 8, the password information is composed of identification information and password information. As the identification information, for example, information such as "PWD" in ASCII code is entered. Then, the actual password information is entered.

[0017] By using such password information, for example, if the recording and reproducing electrocardiogram information from the host computer, enter the password information, only when it matches the password information in the block _61, the access of electrocardiographic information Becomes possible. In contrast, the track 4 _{k + 1,} 4 _{n- 1} to record the password in the block 6 ₂
Has no password information recorded therein, and therefore can freely record and reproduce blood pressure information.

However, when information is recorded on the optical card, the light beam narrowed into a minute spot is modulated according to the recording information, and the modulated light beam is scanned in a direction parallel to the information track. Since the information is recorded as an optically detectable information pit string, even if the access in the block 6 is restricted by the password, when analyzed using an optical microscope or the like, highly confidential information is seen by others. There is also a possibility.

Therefore, in order to further enhance the security, data to be recorded on the optical card is encrypted with an encryption key and recorded, and at the time of reproduction, the encrypted data is decrypted with a decryption key and reproduced. A way to do that has been proposed. By using this method, even if the data recorded on the optical card is analyzed by an optical microscope or the like, the analyzed data becomes meaningless, and the confidentiality of the data recorded on the optical card can be maintained. it can.

Various methods are conceivable for encrypting data to be recorded on the optical card. In particular, public key RSA encryption and common key DES encryption are well known. In order to simplify the description, the Caesar cipher will be described as an example. In the Caesar cipher, the number of alphabets is associated with A = 0, B = 1,..., Z = 25, the number representing one character of plaintext is x, the number representing one character of ciphertext is c,
If the number representing the encryption key is denoted by k, the encryption method is represented by the relational expression of c = (x + k) mod 26. However, (am
odn) indicates the remainder of dividing a by n. In the case of decryption of a ciphertext into a plaintext, it is expressed by a relational expression of x = (c−k) mod 26.

Therefore, in the Caesar encryption, the encryption key and the decryption key are the same key. For example, when the encryption key k is 1, if the plaintext is “ABC”, the ciphertext is encrypted as “BCD”. However, since only the characters of the alphabet can be handled as it is, the encryption formula is extended as c = (x + k) mod 256 and the decryption formula is x = (c−k) mod 256 Thus, all characters represented by one byte can be handled. Since it is desirable that such encryption or decryption be performed at high speed, it is generally performed by hardware.

Next, a method of creating an encryption key will be described. Various methods are conceivable as a method for creating an encryption key.For example, when a user inputs a password to a host computer connected to an optical card information recording / reproducing device, the host computer The password is sent to the optical card information recording / reproducing device. Next, the optical card information recording / reproducing apparatus can create an encryption key by inputting the received personal identification number into a certain function.

Accordingly, if the encryption key is k and the received personal identification number is n, the relational expression of k = F (n) holds. However, the function F (n) is a function for creating an encryption key, and a compression function or the like is used. The compression function is a function for converting a bit string having an arbitrary bit length into a bit string having a certain length. Then, the optical card information recording / reproducing apparatus performs data encryption or decryption of the encrypted data using the encryption key.

Next, an optical card information recording / reproducing apparatus for recording / reproducing information on / from an optical card will be described with reference to FIG. In FIG. 4, reference numeral 31 denotes an optical card information recording / reproducing device.
Are connected to the host computer 32. Also,
Reference numeral 37 denotes a motor via a transport mechanism (not shown).
The optical card 1 is introduced into the optical card information recording / reproducing apparatus, and is reciprocated in the R direction at a predetermined position to scan in a direction parallel to the information track. And to discharge.
Reference numeral 38 denotes a light beam irradiation optical system including a light source, whereby a light beam spot is formed on an optical card during information recording and information reproduction.

Reference numeral 40 denotes an auto-focusing (hereinafter, referred to as AF) actuator which drives a part of the light beam irradiation optical system 38 to shift the focus position of the light beam spot on the optical card surface in the Z direction. That is, the auto-focusing is performed by moving in the direction perpendicular to the optical card surface, and reference numeral 41 denotes an auto-tracking (hereinafter, referred to as AT) actuator, which is a part of the light beam irradiation optical system 38. To move the light beam spot on the optical card surface in the Y direction (the direction perpendicular to the information track).
And auto-tracking.

Reference numeral 39 denotes a photodetector which receives the reflected light of the light beam spot on the optical card 1 and performs AT / AF.
, And an RF signal that is an information reproduction signal. Thus, the light beam irradiation optical system 38, the light detector 39, the AF actuator 40
And the AT actuator 41 together,
The optical head 30 is configured.

Reference numeral 36 denotes a drive motor for moving the optical head 30 in the Y direction so that the light beam spot accesses a desired track on the optical card. Therefore, the head feed motor 36 and the AF actuator 4
0, by controlling the AT actuator 41, track access to a target track is performed.

The MPU 33 includes a ROM and a RAM, and includes a card feed motor 37 and a head feed motor 36.
In addition, under the control of the host computer 32, communication and control between the host computer 32 and data are performed. The AT / AF control circuit 34 includes the photodetector 3
In response to the signal of No. 9, the AT actuator 41 and the AF actuator 40 are controlled based on this signal to perform AT and AF.

The output of the photodetector 39 is RF
The signal is also input to the modulation / demodulation circuit 35, where the read information is demodulated, and the demodulated signal is sent to the MPU 33. The data transferred to the MPU 33 is stored in the RAM
Are sequentially stored, and thereafter, the encrypted data is decrypted by the encryption / decryption circuit 42, and the data is reproduced.

The recording data is sent from the host computer 32 to the MPU 33, and is thereafter encrypted by the encryption / decryption circuit 42. The modulation / demodulation circuit 35
The encrypted data sent from the MPU 33 is modulated, and the light beam irradiation optical system 3 is modulated according to the modulated signal.
8 is driven to execute information recording. The host computer 32 transmits and receives commands and data to and from the optical card information recording / reproducing device 31, and performs recording / reproducing operations of information for each sector on the optical card 1.

The operation of accessing data on an optical card using such an optical card recording / reproducing apparatus will be described with reference to the flowchart of FIG.

First, in step S801 (hereinafter, steps are omitted, and simply described as S801), it is monitored whether an optical card is inserted into the optical card information recording / reproducing apparatus. When the optical card is inserted, first, the format information 9 is reproduced (S802). At this point, it is clear how the recording area of the optical card is divided. Here, the block 61 is automatically selected as a default block, and the password information 101 of the block 61 is reproduced in S803. Password information is MPU
33 is stored in the RAM. If the password has not been recorded, it is stored that the password is not protected.

Next, in step S804, the directory 81 of the block 61 is sequentially reproduced, and this is stored in the RAM in the MPU 33.
To memorize. Since both the data and the directory are sequentially recorded on the optical card, when the directory is reproduced, the recording start position of the directory and the recording start position of the data are determined from the number of reproduced directories and the contents of the reproduced directory.

In order to record and reproduce data, an encryption key used for encryption and a decryption key used for decryption are required. Here, the encryption key and the decryption key are used. A password for creation is entered (S805).
As described above, the user inputs the password from the host computer. When the optical card information recording / reproducing device receives the password, it creates an encryption key and a decryption key using the compression function (S806). As described above, since Caesar encryption is used for encryption, the encryption key and the decryption key are the same.

In step S807, the optical card information recording / reproducing apparatus waits for a command from the host computer, and executes the following processing according to the type of the command. First, S8
At 08, it is checked whether or not the command is a discharge command. If the command is a discharge command, S
At step 809, the optical card is ejected, and the processing for this optical card is completed.

If the command is not a discharge command in step S808, it is checked in step S810 whether the command is a password verification command. If the command is a password collation command, the password is collated in step S811. Here, the password reproduced in S803 and stored in the RAM is compared with the password sent from the host computer by the password comparison command.

If the results match, block 61
MPU3 confirms that the password in
3 is stored in the RAM. If the passwords do not match, the process directly proceeds to the command waiting process in S807. If the currently selected block is not password data protected, no collation is performed and the process returns to S807.

In S812, it is checked whether the command is a block selection command. If it is a block selection command, the password information of the designated block is reproduced in S802 based on the reproduced format information (S813). The reproduced password information is stored in the RAM in the MPU as in S803.
Further, in S814, all directories recorded in the specified block are reproduced, and the RAM in the MPU 33 is reproduced.
And the block selection process ends.

If the command is not a block selection command in S812, the command is a recording command or a reproduction command. If the currently selected block is protected by a password, it is necessary to check whether the password has been verified. First, it is checked whether the block is protected by the password (S815). If the block is protected, the process proceeds to S816. Check if the password has been verified. This check refers to the information stored in the RAM in S811. If the password has not been referenced, the process returns to S807. If the password has already been referred to, or if it is determined in step S815 that the password is not protected, the process advances to step S817.

In S817, it is checked whether or not the command is a recording command. If it is a recording command, in S818, the data sent from the host computer together with the recording command is encrypted using the encryption key created in S806. In S819, the encrypted data is recorded from the position where recording of the selected block should be started. After that, a directory for the recorded data is recorded, a similar directory is stored in the RAM, and the processing of the recording command ends (S820).

In S821, it is checked whether or not the command is a reproduction command. If the command is not a reproduction command, the command returns to S807 because the command is not supported by the optical card information recording / reproducing apparatus. If the command is a reproduction command, a sector address to be reproduced is obtained from the file name specified by the command and the directory stored in the RAM, and the data is reproduced (S822). Since the data reproduced here is encrypted data, S82
In step 3, decryption is performed using the decryption key created in step S806, the decrypted data is transferred to the host computer, and the reproduction process ends.

[0042]

As described above, conventionally,
The optical card was accessed by the above-described device and method.
However, in the above-described conventional example, a password for creating an encryption key is input from the host computer every time an optical card is inserted into the information recording / reproducing apparatus, so that the input operation is troublesome. there were. In addition, if the password for creating the encryption key is forgotten, the correct encryption key and decryption key cannot be created, and the data in the optical card cannot be reproduced again.

In the method of inputting a personal identification number from a host computer, if reproduction is attempted many times while changing the input personal identification number, data in the optical card may be decrypted.

It is also conceivable to record a personal identification number in the data area of the optical card. However, in this case, the data area is reduced by the amount corresponding to the recording of the personal identification number, and the personal identification number is recorded in the data area. In this case, when the data area is analyzed with a microscope or the like, there is a problem that the password may be specified.

In view of the above-mentioned problems, the present invention eliminates the trouble of inputting a password for creating an encryption key while retaining an information recording / reproducing method with high security, and also learns the password. It is an object of the present invention to provide an information recording / reproducing method in which a data area can be effectively used without any need and a password is hardly specified.

[0046]

To achieve the above object, the present invention provides a method for recording / recording data on an information recording medium having a plurality of tracks composed of one or a plurality of sectors.
In an information recording / reproducing apparatus having a reproducing unit, a unit for encrypting data, and a composite unit for decrypting the encrypted data, the information recording medium includes data for encrypting and decrypting data. The key is not recorded. When recording data, an encryption key is created from the information already recorded on the information recording medium to encrypt the data, and when reproducing the data, the data is already recorded on the information recording medium. A decryption key is created from the recorded information to decrypt the encrypted data.

Accordingly, the information recorded in advance on the information recording medium is used as a password for creating an encryption key and a decryption key, so that the trouble of inputting the password is eliminated. The effect that you do not need to remember, the effect that you can not try to enter the PIN,
Since the personal identification number is not recorded in the data area, the data area can be used effectively. In addition, since the information for creating a key is not recorded as a security code and is not easily recognized as a security code, it is difficult to identify a security code when a recording area is analyzed. .

According to an embodiment of the present invention, the information recording / reproducing method includes a means for dividing an information recording medium having a plurality of tracks composed of one or a plurality of sectors into a plurality of blocks; Means for allocating an arbitrary number of tracks to the medium, means for recording / reproducing while changing the sector size and the number of sectors in the block for each block, the number of blocks into which the information recording medium is divided, and each block Means for recording / reproducing format information including the number of tracks in the block and the sector type used in each block, an encryption means for encrypting data, and a decryption means for decrypting the encrypted data. When recording data in an information recording / reproducing apparatus having a key, an encryption key created from the reproduced format information is used. It encrypts the data, when playing data is to decrypt the data with decryption key created from said format information reproduced.

According to another aspect of the present invention, there is provided a data recording / reproducing means for recording / reproducing data on / from an information recording medium having a plurality of tracks each composed of one or a plurality of sectors; Means for recording / reproducing a directory, encryption means for encrypting data,
When recording data in an information recording / reproducing apparatus having decryption means for decrypting encrypted data,
When the data is encrypted with the encryption key created from the directory last recorded on the information recording medium and the data is reproduced, one of the directories for managing the data to be reproduced is used.
Data is decrypted with a decryption key created from the directory recorded immediately before.

Therefore, since the directory already recorded on the information recording medium is used as a password for creating an encryption key and a decryption key, the operation of eliminating the trouble of inputting the password can be achieved. The function of eliminating the need to remember, the function of not being able to try to input a password, and the fact that the password is not recorded in the data area allows the data area to be used effectively. Further, the directory is information for managing data, and it is difficult to notice that the directory is a password, so that it is difficult to identify the password when the recording area is analyzed. Further, since the encryption key is different for each data to be recorded, even if the encryption key of certain data is found, the other data is not decrypted.

Further, in order to achieve the above object, the present invention provides a means for dividing an information recording medium having a plurality of tracks composed of one or a plurality of sectors into one or a plurality of blocks, and Record password information /
In an information recording / reproducing apparatus having a reproducing unit, an encrypting unit for encrypting data, and a decrypting unit for decrypting the encrypted data, when the data is recorded in the block, the data is recorded in the block. Encrypting the data with an encryption key created from the password information and reproducing the data, decrypting the data with a decryption key created from the password information recorded in the block. .

Therefore, the password information pre-recorded on the information recording medium is used as the password for creating the encryption key and the decryption key, so that the trouble of inputting the password is eliminated. , It is not possible to try to input a password, and since the password is not recorded in the data area, the data area can be used effectively. Further, the password information is information for restricting access to the recording area, and it is difficult to recognize that the password information is a password. Therefore, when the recording area is analyzed, it is difficult to specify the password.

Further, since the password information is recorded for each block, the data is encrypted with a different encryption key for each block. Even if the encryption key of a certain block is found, the data is encrypted. There is an effect that data of other blocks is not decoded.

[0054]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. The information recording medium and the information recording / reproducing apparatus used here are the same as those in the conventional example, and the description thereof will be omitted. FIG. 1 is a flowchart showing the operation of the information recording / reproducing method in this embodiment.

Here, first, in S101, it is monitored whether or not an optical card has been inserted into the optical card information recording / reproducing apparatus. When the optical card is inserted, first, the format information 9 is reproduced (S102). Here, an encryption key and a decryption key necessary for encryption and decryption performed at the time of data recording and reproduction are created (S103). In the past, at this time, the password was input from the host computer, so each time the card was inserted, it was troublesome to input it. However, here, the encryption key and the decryption key are automatically Create Therefore, it is possible to save the trouble of inputting the personal identification number, and it is not necessary to memorize the personal identification number, so that an accurate encryption key and decryption key can always be created. Note that the above-described compression function is used for the method of creating the encryption key and the decryption key. Also, in this embodiment, the Caesar encryption is used for encryption, as in the conventional example, so the encryption key and the decryption key are the same.

When the format information is reproduced, it is known how the recording area of the optical card is divided. Also in the present embodiment, the block 61 is automatically selected as a default block. In S104, the password information 101 in the block 61 is reproduced.
This password information is stored in the RAM in the MPU 33. If the password has not been recorded, it is stored that this block is not protected by a password.

Next, in S105, the directory 81 of the block 61 is sequentially reproduced, and the RA in the MPU 33 is reproduced.
Store it in M. Since both the data and the directory are sequentially recorded on the optical card, when the directory is reproduced, the recording start position of the directory and the recording start position of the data are determined from the number of reproduced directories and the contents of the reproduced directory.

In S106, the optical card information recording / reproducing apparatus waits for a command from the host computer, and executes the following processing according to the type of the command. First, S1
At 07, it is checked whether the command is a discharge command. If the command is a discharge command,
In step S108, the optical card is ejected, and the processing for the optical card ends.

If the command is not a discharge command in S107, it is checked in S109 whether the command is a password verification command. If the command is a password collation command, the password is collated in S110.
Here, the password reproduced in S104 and stored in the RAM is collated with the password transmitted from the host computer by the password collation command. If the results match, it is determined that the password in block 61 has been verified by the R in the MPU 33.
Store it in the AM.

If the passwords do not match, the process directly proceeds to the command waiting process in S106. If the currently selected block is not protected by the password, the process returns to S106 without performing collation.

In S111, it is checked whether or not the command is a block selection command. If the command is a block selection command, the password information of the designated block is reproduced based on the format information reproduced in S102 (S112). The played password information is
As in S104, the data is stored in the RAM in the MPU. Further, in S113, all the directories recorded in the designated block are reproduced, stored in the RAM in the MPU 33, and the block selection processing is ended.

If the command is not a block selection command in S111, the command is a recording command or a reproduction command. The currently selected block is
If it is protected by a password, it is necessary to check whether or not the password has been collated. First, it is checked whether or not the password is protected (S114). Check if not. This check refers to the information stored in the RAM in S110. If the password has not been referenced, the process returns to S106. If the password has been referred to, or if it is determined in step S114 that the password is not protected, the process proceeds to step S116.

In S116, it is checked whether the command is a recording command. If it is a recording command, in step S117, the data transmitted from the host computer together with the recording command is encrypted using the encryption key created from the format information in step S103. In S118, the encrypted data is recorded from the position where the recording of the currently selected block should be started. Thereafter, a directory relating to the recorded data is recorded, a similar directory is also stored in the RAM, and the processing of the recording command ends (S119).

In S120, it is checked whether the command is a reproduction command. If the command is not a playback command, the command returns to S106 because the command is not supported by the optical card information recording / reproducing apparatus. If the command is a reproduction command, a sector address to be reproduced is obtained from the file name specified by the command and the directory stored in the RAM, and the data is reproduced (S121). Since the data reproduced here is encrypted data, S122
In step S103, the data is decrypted using the decryption key created from the format information in step S103, and the decrypted data is transferred to the host computer.

In this embodiment, as described above, the encryption key and the decryption key are automatically created from the format information previously recorded on the information recording medium, as compared with the conventional example. In addition, the trouble of inputting the password can be eliminated. Further, unlike the related art, there is no need to memorize the personal identification number, so that the user cannot forget the personal identification number and cannot reproduce the data in the optical card. Further, since the personal identification number is not recorded in the data area, the data area can be used effectively. Also, the format information is information indicating how the recording area is divided, and it is difficult to notice that the recording area is a password. Therefore, when the recording area is analyzed, the password is hard to be specified.

The following examples can be given as modifications of the present invention. (1) In the above embodiment, the Caesar encryption is used as the encryption algorithm, but another encryption algorithm such as DES may be used. DES is a more secure information recording / reproducing method because it is more complicated and harder to decipher than the Caesar cipher. (2) In the above embodiment, the format information includes identification information, the number of block divisions, the number of information tracks of each block,
Although the information is constituted by the sector type of each block, other information such as the date and time when the optical card was formatted and a random number may be included. If the date and time information thus formatted is included, even if the optical card is of the same division number and the same sector type, the date and time when the optical card is formatted usually differs for each card. The information recording / reproducing method is such that the decryption key is different for each card, and the security can be further improved.
The same effect can be obtained even if a random number is included in the format information. (3) In the above embodiment, an optical card is used as an information recording medium. However, the present invention is not limited to an optical card, and any type of write-once information recording medium on which format information is recorded can be used. A similar effect can be obtained with a simple information recording medium. (Second Embodiment) Hereinafter, a second embodiment of the present invention will be described in detail with reference to the drawings. The information recording medium and the information recording / reproducing apparatus used here are the same as those in the conventional example, and the description is omitted. Note that FIG.
6 is a flowchart showing an operation of the information recording / reproducing method according to the embodiment.

Here, first, in S201, it is monitored whether an optical card has been inserted into the optical card information recording / reproducing apparatus. When the optical card is inserted, first, the format information 9 is reproduced (S202). When the format information is reproduced, it is known how the recording area of the optical card is divided. Also in this embodiment, the block 61 is automatically selected as a default block. Then, in S203, the password information 201 of the block 61 is reproduced. The password information is stored in the RAM in the MPU 33. If the password has not been recorded, it is stored that this block is not protected by a password.

Next, in S204, the directory 81 of the block 61 is sequentially reproduced, and is stored in the RAM in the MPU 33.
Store them in the order in which they were read. Since data and directories are sequentially recorded on the optical card, when the directories are played, the number of played directories and
The recording start position of the directory and the recording start position of the data are obtained from the contents of the reproduced directory.

In S205, the optical card information recording / reproducing apparatus waits for a command from the host computer, and executes the following processing according to the type of the command. First, S20
At 6, it is checked whether the command is a discharge command. If the command is a discharge command, S
In step 207, the optical card is ejected, and the processing for the optical card is completed.

If the command is not a discharge command in S206, it is checked in S208 whether the command is a password collation command. If the command is a password collation command, the password is collated in S209. Here, the password reproduced in S203 and stored in the RAM is collated with the password transmitted from the host computer by the password collation command. If the results match, the fact that the password in block 61 has been verified is stored in the RAM within MPU 33. If the passwords do not match, the process directly proceeds to the command waiting process in S205. If the currently selected block is not protected by a password, no collation is performed and the process returns to S205.

In S210, it is checked whether or not the command is a block selection command. If the command is a block selection command, the password information of the designated block is reproduced based on the format information reproduced in S202 (S211). Then, the reproduced password information is stored in the RAM in the MPU 33 as in S203. Further, in S212, all the directories recorded in the designated block are reproduced, stored in the RAM in the MPU 33 in the order of reading, and the block selection processing ends.

If the command is not a block selection command in S210, the command is a recording command or a reproduction command. If the currently selected block is protected by a password, it is necessary to check whether the password has been verified. First, it is checked whether the block is protected by the password (S213). In S214, it is checked whether the password has been verified. This check refers to the information stored in the RAM in S209. If the password has not been referenced, the process returns to S205. If the password has already been referred to, or if it is determined in step S213 that the password is not protected, the next step S215
Move to

In S215, it is checked whether the command is a recording command. If it is a recording command, in S216, an encryption key required for encryption is created. Here, the encryption key is created based on the last directory stored in the RAM. This directory is the last directory recorded in the currently accessed block. If the data is to be recorded for the first time in this block, no directory has been recorded in this block yet, and in this case, an encryption key is created based on a predetermined default value. Conventionally, a password has been input from a host computer, so that it was troublesome to input it every time a card was inserted. In this case, an encryption key is automatically created from a directory. Therefore, it is possible to save the trouble of inputting the personal identification number, eliminate the need to memorize the personal identification number, and always create an accurate encryption key and decryption key. Note that the above-described compression function is used for the method of creating the encryption key.

In S217, the data sent from the host computer together with the recording command is transmitted to S21.
In step 6, encryption is performed using the encryption key created from the directory. In S218, the encrypted data is recorded from the position where the recording of the currently selected block should be started. Thereafter, a directory for the recorded data is recorded, a similar directory is stored in the RAM, and the processing of the recording command ends (S219).

As described above, since the encryption key for the data to be recorded is created from the previously recorded directory, the encryption key differs for each data to be recorded. Even so, other data cannot be decrypted.

In S220, it is checked whether or not the command is a reproduction command. If the command is not a playback command, the command returns to S205 because the command is not supported by the optical card information recording / reproducing apparatus. If the command is a reproduction command, a decryption key is created in S221. The decryption key is created by searching a directory stored in the RAM for a directory of data to be reproduced and based on a directory immediately before the directory. If there is no previous directory, a decryption key is created based on a predetermined default value.

Next, a sector address to be reproduced is obtained from the file name specified by the recording command and the directory stored in the RAM, and the data is reproduced (S22).
2). Since the data reproduced here is the encrypted data, it is decrypted using the decryption key created in S221, the decrypted data is transferred to the host computer, and the reproduction process ends (S223).

In this embodiment, as described above, the encryption key and the decryption key are automatically created from the directory recorded on the information recording medium as compared with the conventional example. Troublesomeness can be eliminated. Further, unlike the related art, there is no need to memorize the personal identification number, so that the user cannot forget the personal identification number and cannot reproduce the data in the optical card. Further, since the personal identification number is not recorded in the data area, the data area can be used effectively.

Further, the directory is information for managing data, and it is difficult to recognize that the directory is a password. Therefore, when the recording area is analyzed, the password is hard to be specified. Furthermore, since the encryption key is different for each data, even if the encryption key of a certain data is found, the other data is not decrypted and all the recording areas are encrypted with a single encryption key. Higher security can be realized as compared with.

In the above embodiment, the Caesar encryption is used as the encryption algorithm, but another encryption algorithm such as DES may be used. DES is a more secure information recording / reproducing method because it is more complicated and harder to decipher than Caesar encryption. In the above embodiment, an optical card is used as an information recording medium. However, the present invention is not limited to an optical card, and any information recording medium of a write-once type in which a directory is recorded can be used. However, the same effect can be obtained. (Third Embodiment) Hereinafter, a third embodiment of the present invention will be described in detail with reference to the drawings. The information recording medium and the information recording / reproducing apparatus used here are the same as those in the conventional example, and the description thereof will be omitted. In the third embodiment, it is assumed that the password information can be recorded only once in an unrecorded block in which no data has been recorded. FIG. 3 is a flowchart showing the operation of the information recording / reproducing method according to this embodiment.

Here, first, in S301, it is monitored whether an optical card has been inserted into the optical card information recording / reproducing apparatus. When the optical card is inserted, first, the format information 9 is reproduced (S302). When the format information is reproduced, it is known how the recording area of the optical card is divided. Also in this embodiment, the block 61 is automatically selected as a default block. Then, in S303, the password information 101 of the block 61 is reproduced. The password information is stored in the RAM in the MPU 33.

If no password has been recorded, it is stored that this block is not protected by a password. Here, an encryption key and a decryption key necessary for encryption and decryption performed at the time of recording and reproducing data are created from the reproduced password information (S304).
If no password information is recorded in the block, an encryption key and a decryption key are created using a certain default value.

Conventionally, at this time, since the personal identification number was input from the host computer, it was troublesome to input the password every time the card was inserted. However, here, the encryption key is automatically obtained from the reproduced password information. Create a decryption key.
Therefore, it is possible to save the trouble of inputting the personal identification number, and it is not necessary to memorize the personal identification number, so that an accurate encryption key and decryption key can always be created. Note that the above-described compression function is used to create the encryption key and the decryption key. Also, in this embodiment, as in the conventional example, since the Caesar encryption is used for encryption, the encryption key and the decryption key are the same.

Next, in step S305, the directory 81 of the block 61 is sequentially reproduced and stored in the RAM in the MPU 33. Since both the data and the directory are sequentially recorded on the optical card, when the directory is reproduced, the recording start position of the directory and the recording start position of the data are determined from the number of reproduced directories and the contents of the reproduced directory.

In step S306, the optical card information recording / reproducing apparatus waits for a command from the host computer, and executes the following processing according to the type of the command. First, S30
At 7, it is checked whether the command is a discharge command. If the command is a discharge command, S3
At 08, the optical card is ejected, and the processing for this optical card is terminated.

If it is determined in step S307 that the command is not a discharge command, it is checked in step S309 whether the command is a password verification command. If the command is a password collation command, the password is collated in S310. Here, the password reproduced in step S303 and stored in the RAM is collated with the password transmitted from the host computer by the password collation command.
If the result matches, the fact that the password in block 61 has been verified is stored in RAM in MPU 33.
To memorize it. If the passwords do not match,
The process directly proceeds to the command waiting process in S306. If the currently selected block is not protected by the password, no collation is performed and the process returns to S306.

In S311, it is checked whether or not the command is a block selection command. If the command is a block selection command, the password information of the designated block is reproduced based on the format information reproduced in S302 (S312). In this case, the reproduced password information is stored in the RAM in the MPU as in S303.

When the block to be accessed is changed, the password information recorded for each block is different, so that the encryption key and the decryption key must be recreated. Therefore, an encryption key and a decryption key are created from the reproduced password information (S313). S3
Similarly to the case of 04, if password information is not recorded, an encryption key and a decryption key are created using a certain default value.

As described above, every time the block to be accessed is changed, the encryption key is changed.
If one block's encryption key is breached, the other blocks remain unbreakable. Further, in S314, all the directories recorded in the designated block are reproduced, stored in the RAM in the MPU 33, and the block selection processing ends.

If the command is not a block selection command in S311, the command is a recording command or a reproduction command. If the currently selected block is protected by a password, it is necessary to check whether or not the password has been verified. First, it is checked whether the block is protected by the password (S315). In S316, it is checked whether the password has been verified. This check refers to the information stored in the RAM in S310. If the password has not been referenced, the process returns to S306. When the password has been referred to and when it is determined in step S315 that the password is not protected, the process proceeds to the next step S317.

In S317, it is checked whether the command is a recording command. If it is a recording command, in S318, the data sent from the host computer together with the recording command is encrypted in S304 or S313 using an encryption key created from the password information. In S319, the encrypted data is recorded from the position where recording of the currently selected block should be started. Thereafter, a directory for the recorded data is recorded, a similar directory is stored in the RAM, and the processing of the recording command ends (S32).
0).

In S321, it is checked whether or not the command is a reproduction command. If the command is not a playback command, the command returns to S306 because the command is not supported by the optical card information recording and playback device. If the command is a reproduction command, a sector address to be reproduced is obtained from the file name specified by the command and the directory stored in the RAM, and the data is reproduced (S322). Since the data reproduced here is encrypted data, it is decrypted in S323 using the decryption key created from the password information in S304 or S333, and the decrypted data is transferred to the host computer. The reproduction process ends.

In this embodiment, as described above, the encryption key and the decryption key are automatically created from the password information pre-recorded on the information recording medium, as compared with the conventional example. The trouble of inputting the password can be eliminated. Further, unlike the related art, there is no need to memorize the personal identification number, so that the user cannot forget the personal identification number and cannot reproduce the data in the optical card. Further, since the personal identification number is not recorded in the data area, the data area can be used effectively. In addition, the password information is information for restricting access to the recording area, and it is difficult to recognize that the password is a password. Therefore, when the recording area is analyzed, the password is hard to be specified.

Further, the password information is recorded for each block, and can be encrypted with a different encryption key for each block. However, other blocks are not decrypted, and higher security can be realized in all the recording areas as compared with the case where encryption is performed with a single encryption key.

In the above embodiment, the Caesar encryption is used as the encryption algorithm, but another encryption algorithm such as DES may be used. As described above, DES is an information recording / reproducing method with higher security since it is more complicated and harder to decipher than the Caesar cipher. Further, in the above embodiment, the optical card is used as the information recording medium. A similar effect can be obtained with a medium.

[0096]

According to the present invention, as described above, the management information pre-recorded on the information recording medium is used as a password for creating an encryption key and a decryption key. This has the effect of eliminating the trouble of performing. Also,
Since there is no need to remember the password, there is an effect that the data in the optical card cannot be reproduced by forgetting the password. Further, since the personal identification number is not recorded in the data area, the data area can be used effectively. In addition, since format information is used as information for creating an encryption key and a decryption key, it is difficult to recognize that the password is a password, and it is difficult to identify the password when the recording area is analyzed. effective.

Also, in the present invention, since a directory is used as information for creating an encryption key and a decryption key, it is difficult to recognize that the password is a password. Has the effect of making it difficult to identify In addition, since the encryption key is different for each data to be recorded, there is an effect that higher security can be realized in all the recording areas as compared with the case where encryption is performed with a single encryption key. Furthermore, if DES is used as the encryption algorithm, the encrypted data is more complicated and harder to decipher, so that there is an effect that the security becomes higher.

According to the present invention, password information recorded in advance on an information recording medium is used as a password for creating an encryption key and a decryption key, thereby saving the trouble of inputting a password. effective. Further, since it is not necessary to remember the password, there is an effect that the data in the optical card cannot be reproduced by forgetting the password. Further, the password information is information for restricting access to the recording area, and it is difficult to recognize that the password is a password. Therefore, when the recording area is analyzed, it is difficult to specify the password. As described above, as the encryption algorithm,
If DES is used, the encrypted data is more complicated and difficult to decipher, so that there is an effect that the security is higher.

Further, the password information is recorded for each block, and the data can be encrypted with a different encryption key for each block. There is also an effect that higher security can be realized as compared with the case where encryption is performed using a key.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining an information recording / reproducing method according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating an information recording / reproducing method according to a second embodiment of the present invention.

FIG. 3 is a flowchart illustrating an information recording / reproducing method according to a third embodiment of the present invention.

FIG. 4 is a block diagram of an information recording / reproducing apparatus used in the present invention and a conventional example.

FIG. 5 is a schematic diagram of an information recording medium used in the present invention and a conventional example.

FIG. 6 is a diagram showing the number of sectors and the sector size of each sector type.

FIG. 7 is a diagram showing an example of format information.

FIG. 8 is a diagram showing an example of password information.

FIG. 9 is a diagram showing an example of a directory.

FIG. 10 is a flowchart for explaining a conventional information recording / reproducing method.

[Explanation of symbols]

 Reference Signs List 1 optical card 2 recording area 3 tracking track 4 information track 5 physical track number 6 block 7 data 8 directory 9 format information 10 password 31 information recording / reproducing device 32 host computer 33 MPU 34 AT / AF control circuit 35 modulation / demodulation circuit 36 head feed motor 37 Card Feed Motor 38 Light Beam Irradiation Optical System 39 Photo Detector 40 AF Actuator 41 AT Actuator 42 Encryption / Decryption Circuit

Claims (8)

[Claims] An information recording medium having a plurality of tracks composed of one or a plurality of sectors.
In an information recording / reproducing apparatus having a reproducing unit, a unit for encrypting data, and a composite unit for decrypting the encrypted data, the information recording medium includes data for encrypting and decrypting data. The key is not recorded. When recording data, an encryption key is created from the information already recorded on the information recording medium to encrypt the data, and when reproducing the data, the data is already recorded on the information recording medium. An information recording / reproducing method wherein a decryption key is created from recorded information to decrypt encrypted data. 2. A means for dividing an information recording medium having a plurality of tracks composed of one or a plurality of sectors into a plurality of blocks; a means for allocating an arbitrary number of said tracks to each of said blocks; Means for recording / reproducing while changing the sector size and the number of sectors of each sector in each block, and the number of blocks into which the information recording medium is divided, the number of tracks in each block, and the sector type used in each block. When recording data in an information recording / reproducing apparatus including a unit for recording / reproducing the configured format information, an encrypting unit for encrypting the data, and a decrypting unit for decrypting the encrypted data, When encrypting data with an encryption key created from the reproduced format information and reproducing the data, 2. The information recording / reproducing method according to claim 1, wherein data is decrypted using a decryption key created from the format information. 3. The information recording / reproducing method according to claim 2, wherein the format information includes date and time information. 4. A means for recording / reproducing data on / from an information recording medium having a plurality of tracks composed of one or a plurality of sectors; a means for recording / reproducing a directory which is management information of the data; In an information recording / reproducing apparatus having an encrypting means for encrypting and a decrypting means for decrypting the encrypted data, when recording data, when the data is recorded, the encryption created from the directory recorded last on the information recording medium is used. Encrypting the data with a decryption key and reproducing the data, decrypting the data with a decryption key created from a directory recorded immediately before a directory for managing the data to be reproduced. Item 2. An information recording / reproducing method according to Item 1. 5. The information according to claim 4, wherein, when no directory is recorded on the information recording medium, an encryption key and a decryption key are created from predetermined default values. Recording and playback method. 6. A means for dividing an information recording medium having a plurality of tracks constituted by one or a plurality of sectors into one or a plurality of blocks, means for recording / reproducing password information in each block, and encrypting data. In an information recording / reproducing apparatus having an encrypting unit for encrypting and a decrypting unit for decrypting the encrypted data, when recording data in the block, the data is created from the password information recorded in the block. 2. The information recording apparatus according to claim 1, wherein when the data is encrypted with an encryption key and the data is reproduced, the data is decrypted with a decryption key created from password information recorded in the block. Playback method. 7. The information recording / reproducing method according to claim 6, wherein if password information is not recorded in the block, an encryption key and a decryption key are created from predetermined default values. . 8. The information recording / reproducing method according to claim 1, wherein the information recording medium is an optical card.