JPH0728406A - Scrambling method - Google Patents

Abstract

PURPOSE:To provide the scrambling method which is high in security by providing a deciphering step wherein data ciphered in a ciphering step are restored by using key data obtained by a key data read step for deciphering. CONSTITUTION:The scrambling method which scrambles a data series on the basis of the key data has a the key data read step 110 for ciphering wherein the key data stored in a storage device are read out, and the ciphering step 120 wherein the data 150 to be ciphered are ciphered by using the key data read out in the key data read step for ciphering. The original restored data 190 are obtained through a key data read step 130 for deciphering wherein the key data stored in the storage device are read out and a restoration step 140 wherein the data 170 ciphered in the ciphering step 120 are restored by using the key data read out in the key data read step 130 for deciphering.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scrambling method for encrypting data to be stored in a file and improving security so that only a rightful person can decrypt the original data.

[0002]

2. Description of the Related Art Conventionally, in this type of scrambling method, the scrambling key data used for encryption is stored in an area such as a disk as shown in FIG. 6 and is used for subsequent decoding. Referring to FIG. 6, the encrypted data 170 in the memory 210 is decrypted into the original data 150 based on the scrambling key data 160 stored in the disc. For example, JP-A-59-1
In Japanese Patent No. 73847, the scrambling key data generated by a random number is stored in a file control area of a floppy disk, and the decryption process is performed by referring to the scrambling key data at the time of decryption. Protective method and its device ". In such a conventional method, since the scramble key data is stored in the disc, it is possible to refer to the scramble key data used for encryption by one application from another application and use it for the decryption process. It is possible, and it has a feature that different scramble key data can be set for each system.

[0003]

However, in such a conventional scrambling method, since the scrambling data used for decoding is stored in the disc, the security measure is insufficient and the scrambling data is read out. If it is, the encrypted data may be decrypted into the original data. Further, if the scramble data is updated by another application, there is a problem that the original data cannot be restored.

[0004]

In order to solve the above-mentioned problems, in the present invention, in a scrambling method for scrambling a data sequence based on key data,
An encryption key data reading step for reading the key data stored in the storage device, and an encryption step for encrypting the data to be encrypted using the key data read by the encryption key data reading step. , A decryption key data read step of reading out the key data stored in the storage device, and a data encrypted by the encryption step by using the key data read out by the decryption key data read step. And a decoding step of restoring.

Further, an encryption key data creating step of creating key data and storing the key data in a storage device, and an encryption using the key data read in the encryption key data reading step An encryption step of encrypting the data to be encrypted, a decryption key data read step of reading the key data stored in the storage device by the encryption key data creation step, and a decryption key data read step And decrypting the data encrypted by the encryption step using the encrypted key data.

[0006]

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

Referring to FIG. 1, a scrambling method according to an embodiment of the present invention includes an encryption procedure including an encryption key data reading step 110 and an encryption step 120, and a decryption key data reading step 130. And a decoding step 140 including a decoding step 140.

As a procedure for encrypting confidential data, the encryption key data reading step 110 reads the encryption key data included in the application.
In the present embodiment, it is assumed that this encryption key data is written in the program when the application program is created. That is, it is assumed that the key data is expanded on the memory during execution of the program.

Then, in the encryption step 120, the encryption key data read out in the encryption key data reading step 110 is used to encrypt the data 150 to be scrambled (encrypted). .
As a result, encrypted data 170 is obtained.

On the other hand, as a procedure for restoring the encrypted data 170, the decryption key data reading step 130 reads the decryption key data included in the application. This decryption key data is the same as the encryption key data used at the time of encryption and is also written in the program when the application program is created.

Thereafter, the decryption step 140 uses the decryption key data read by the decryption key data read step 130 to generate the encrypted data 170.
To restore. As a result, the original data 190 can be obtained.

Referring to FIG. 2, the encrypted data 170 is obtained by taking the bitwise exclusive OR of the original data 150 to be scrambled and the encryption key data 160. Here, the reason why the encryption by exclusive OR is adopted as the scramble method is as follows. First, it should be a simple algorithm. Second
In addition, it must be a scramble algorithm that can be decoded.
Regarding the latter, depending on the OS, when scrambling a password file or the like, an undecipherable cipher may be used under the assumption that the encrypted data may be collated with each other. However, in the present invention, a decryptable encryption method is selected so that decrypted data can be used for various applications.

Referring to FIG. 3, the encryption step 120.
The encrypted data 170 encrypted by the above is decrypted into the original data 190 by taking the exclusive OR for each bit with the decryption key data 180 read in the decryption key data reading step. It The decryption key data 180 used for decryption is, of course, the encryption key data 160 used for encryption.
Is the same as Utilizing the property of exclusive OR,
In this way, the decryption can be performed easily.

Referring to FIG. 4, in the present invention, when the original data 190 is restored by the exclusive OR of the encrypted data 170 and the decryption key data 180, the decryption key data 180 is the application program 220. Use the one written from the beginning. That is, since the key data is inserted at the coding stage of the application program, it is difficult for others to know the key data from the compiled executable file. Moreover, since the application is expanded in the memory during the program execution, it is still difficult to check the key data. As described above, in the present invention, by inserting the key code into the program, it is possible to prevent others from stealing the key code and making the original data known.

Next, another embodiment of the scrambling method of the present invention will be described with reference to the drawings.

In the above embodiment, the key data is inserted at the coding stage of the application program, but in order to save this trouble, it is possible to generate the key data from a random number function prepared by the system when the program is executed. Is.

Referring to FIG. 5, a scrambling method according to another embodiment of the present invention is an encryption procedure including an encryption key data creating step 310 and an encryption step 120, and a decryption key data reading step. The decoding procedure comprises a decoding step 130 and a decoding step 140. That is, the encryption key data creation step 310
The point that the key data is created in is different from the embodiment of FIG. In the embodiment of FIG. 5, in the encryption key data creation step 310, the key data 350 is generated by using a random number or the like. The key data 350 is used for encryption in the encryption step 120 and is stored in the application program work area in the memory.

On the other hand, in the decryption key data read step 130, the key data stored in the encryption key data creation step 310 is read from the application program work area in the memory. As a result, the key data can be automatically created at the time of execution without directly writing the key data in the application program as in the embodiment of FIG. 1, and the key data can be flexibly added. Moreover, since the key data is not stored in a disk or the like and only passes through the application program work area in the memory, it is difficult for others to know the key data.

[0019]

As described above, according to the present invention,
A scramble method with high security is realized by previously inserting key data for scrambling when creating an application program and reading the key data from the memory when the program is executed. Further, by creating the key data for scrambling at the time of executing the program and holding it in the memory, it is possible to save the trouble of putting the key data in the program. Moreover, since the security of the key data is high, a simple scramble algorithm can be adopted, and the load of encryption / decryption can be suppressed.

[Brief description of drawings]

FIG. 1 is a procedure diagram of an embodiment of a scrambling method of the present invention.

FIG. 2 is an explanatory diagram of encryption according to the present invention.

FIG. 3 is an explanatory diagram of decoding according to the present invention.

FIG. 4 is an explanatory diagram of an embodiment according to the present invention.

FIG. 5 is a procedure diagram of another embodiment of the scrambling method of the present invention.

FIG. 6 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 110 encryption key data read step 120 encryption step 130 decryption key data read step 140 decryption step 150 original data 160 encryption key data 170 encrypted data 180 decryption key data 190 restored original Data 210 Memory 220 Application 250 Disk 310 Encryption key data creation step 350 Key data

Claims (2)

[Claims] 1. A scramble method for scrambling a data sequence based on key data, comprising: an encryption key data read step of reading key data stored in a storage device; and a read step of the encryption key data read step. An encryption step of encrypting the encryption target data using the issued key data, a decryption key data read step of reading the key data stored in the storage device, and a decryption key data read step And a decryption step of recovering the data encrypted by the encryption step using the key data read by the. 2. A scrambling method for scrambling a data sequence based on key data, the key data creating step for creating key data and storing the key data in a storage device; An encryption step of encrypting the data to be encrypted using the key data read by the key data reading step, and a decryption key for reading the key data stored in the storage device by the encryption key data creation step A scramble method comprising a data reading step and a decrypting step of restoring the data encrypted by the encrypting step using the key data read by the decrypting key data reading step.