JPS61168061A - Data protecting system - Google Patents

Abstract

PURPOSE:To protect data from appropriation, by storing data in a main memory after coding whenever writing control is made from a CPU to a memory and decoding the data whenever readout is performed from the memory to the CPU after a code key circuit operates by means of a decoding circuit. CONSTITUTION:When data is enciphered, a CPU1 actuates a code key circuit 4 and data are coded whenever the data outputted when the CPU1 writes in a memory pass through a enciphering circuit 3 after the enciphering circuit 3 is set. The enciphered data is stored in the memory through a data bus 9. On the other hand, when the data is decoded, the CPU1 actuates the code key circuit 4 and data is decoded whenever the data passes through an enciphering circuit 5 when the CPU1 reads out data from the memory after the enciphering circuit 5 is set.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is directed to data theft and eavesdropping by encrypting and decoding data produced and used in computer systems. We are deeply concerned about the prevention of this.

[The sorcery of Jubei]

Traditionally, this method has been used to prevent theft and eavesdropping on stocks.

Broadly divided into three methods N! In order to prevent unauthorized access to the data while the data is intact, a valley keyword is established in the hardware and software to prevent a second party from accessing the data. The second method is to monitor and thread the stem, the second method is to encrypt the data itself, and the encryption device or circuit gold film is used for each device where the human output of normal data is entered. How to get it.

[Problem that the invention seeks to solve]

In the above-mentioned method, the first method requires the system to constantly manage the keys that are used against the data, and a third party can easily stealth the key by stealing the key. In addition, in the second method, since the encryption circuit is black in the central processing bah, it is necessary to have an encryption circuit or device for all systems in which data is output manually. However, the input/output device itself is expensive, and 1) the processing is complicated because control is performed for each IT encoding circuit.

[Means for determining the inter-grouping point]

Unexploded BAh, between the main memory and the CPU, there is an encryption circuit for loading data into the main memory, a data decoding circuit for outputting data from the main memory, and a cipher that controls each circuit. I'm leaning over the key circuit.

When data is written to the main memory, data is encrypted by operating an encryption key circuit and making it possible to manufacture an encryption circuit. This encrypted data is then decrypted by the decryption circuit after the encryption circuitless operation.
Data is decoded each time it is transferred from memory to the CPU.

〔Example〕

Next, the implementation rJK of the non-invention will be explained with reference to all the drawings.

This is a block diagram of an embodiment of the invention, 1 is a central processing unit 1llic ((, PU), 2t
．． 3 is an encryption circuit, 4 is an encryption key circuit, 5 is an encryption circuit system, 6 is an encryption circuit start line, and 7 is a decryption circuit start line M1m.
11.8 company instruction fitch control 1x, 9 is a data bus.

In this embodiment, data encryption and decryption operations will be explained separately.

(b) When encrypting the encrypted production data, the CPU 1 activates the encryption key circuit 4, sets the encryption circuit 3, and then outputs the data to the encryption circuit 3 when the CPU 1 writes it into the memory. The data is encrypted each time it passes through the data bus 9.
is stored in memory via . Further, when a program is stored or when no encryption is performed, the data is stored in the memory without being encrypted by stopping the encryption key circuit 4t.

(b) Decoding of decoding operation data is performed when successively outputting from memory to pcPU, and the ambiguous code of CPU j″i4 of l
After starting the 1st knot and setting the 5th decoding circuit.

When the 1 CPLI retrieves data from the memory, the data is decoded every time the data passes through the 5 decoding circuits. Similarly, when the CPU executes a program, data from the memory passes through the decoding circuit, but at that time, the decoding circuit does not operate due to the command twitch control line 8, and the data passes through the decoding circuit, and is The input is traced to the CPUI and executed.

〔Effect of the invention〕

That’s all rI5! As explained above, since the present invention is composed of three circuits and a control 14I for controlling them, the circuits can be unified, so there is no need for conventional keys for data, and even if the encryption of the present invention is Even if the activation method of the key circuit is stolen, the data will not be usable because there is no decryption circuit in other CPUs, and there is a sufficient defensive effect against data theft and eavesdropping. . Moreover, since it is connected to the CPU, it is not connected to external equipment, and has the effect of allowing the use of normal equipment.

[Brief explanation of the drawing]

1 is a block diagram showing an embodiment of the present invention. 1... Central location! ailc (CPU), 2...
...Decryption circuit, 3...Encryption circuit, 4...
... Encryption key circuit, 5... Encryption circuit control line, 6... Encryption circuit starting line, 7... Decryption circuit starting edge, 8... ... Command twitch control edge,
9...Data bus.

Claims (1)

[Claims] In a data processing device that is configured around at least one central processing unit (hereinafter abbreviated as CPU), there is a data encryption/decryption circuit that inputs data from a main memory to the CPU and outputs data to the main memory. A data protection system that prevents eavesdropping on software data consisting of a data encryption circuit and an encryption key circuit that controls the two circuits.