JPH0697443B2 - Data processing device - Google Patents

Description

The present invention relates to a data processing device having a storage unit for storing specific data such as keywords or programs necessary for data processing.

[Prior Art] In a data processing device, a keyword for encoding a personal identification number recorded on various cards such as credit cards, or conversely decoding a personal identification number input from an input unit is stored in an internal storage unit. There is a device which stores the input data and processes the input data based on the data such as the keyword. In such an apparatus, if a keyword in the storage unit is known to a third party, a credit card or the like can be misused, so that it is necessary to take measures so that important data such as the keyword cannot be read. In general,
The storage unit is equipped with a backup power supply so that the stored contents will not be lost even if the main power supply is turned off. For this reason,
If the device housing can be disassembled while the power from the pack-up power supply is being supplied, the data in the storage unit can be read. Therefore, conventionally, a micro switch or an optical sensor is provided in the housing, and when the housing is disassembled, the backup power supply of the storage unit is cut off to prevent the theft of important data such as keywords.

[Problems to be Solved by the Invention] However, in the above-mentioned means for preventing the theft of important data, the backup power supply of the storage unit is cut off when the housing is disassembled, but the housing is supplied with the main power. It was possible to read data from the storage unit once the data was disassembled.

Therefore, an object of the present invention is to provide a data processing device capable of preventing the theft of important data such as keywords even if the data is read by the power supply from the main power supply and improving the reliability.

[Means for Solving Problems] The present invention includes a power switch that is input when disassembling the housing, and a disassembly detection switch that detects that the housing has been disassembled and outputs an interrupt command. In response to the interruption command of the disassembly detection switch, at least the specific data stored in the storage unit is rewritten by the data rewriting means.

[Operation] By taking such a means, when the housing is disassembled, at least the specific data in the storage unit is rewritten in response to the interrupt signal from the disassembly detection switch. There is no risk of plagiarism.

[Embodiment] An embodiment in which the present invention is applied to a keypad for inputting a personal identification number in a credit card system will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a credit card system,
In the figure, reference numeral 1 denotes a credit terminal device such as an electronic cash register which can also be approved by a credit card, and is centrally managed by a host computer 2 connected online. A keypad 3 functions as a data processing device of the present invention, and performs data transmission with the credit terminal device 1 by optical communication using infrared light emission. The housing 4 of the keypad 3 can be disassembled into an upper cover 5 and a lower cover 6, and the upper cover 5
Is a keyboard 7 for the customer to input a personal identification number, a display 8 for displaying the input data from the keyboard 7 or the transmission data from the credit terminal 1, and a card reader for reading the data recorded in the credit card. Although not shown, the lower cover 6 is provided with a power switch 10 for turning on the main power. In addition, in the credit terminal 1, 11 is a keyboard for inputting a product code, sales amount, sales points, etc. of a sales evaluation item, 12 is an operator display for displaying the sales amount, the total amount, etc., and 13 is A printer unit with a built-in printer for printing the product name, sales price, total price, etc. on receipts and journals, 14 is a card reader, and 15 is a drawer for storing cash.

FIG. 2 is a block diagram of the keypad 3. CPU
The (central processing unit) 21 has a built-in arithmetic circuit, memory control circuit, etc., performs various arithmetic operations based on input data from the keyboard 7, cart reader 9, etc., and also via the address bus 22 and data bus 23. A ROM (24) for storing fixed data such as a control program and a RAM (26) having a key memory (25) for storing a keyword for decoding a personal identification number are operated. Further, a keyboard input circuit 27 for inputting a key signal from the keyboard 7, a display control circuit 28 for driving the display 8 to display characters or the like corresponding to the display data,
The card reader control circuit 29 for driving the card reader 9 to read the recorded data from the credit card 9 and the optical communication interface 30 for controlling the data transmission by the optical communication with the credit terminal 1, the CPU 2 via the bus line 23.
Connected to 1. Further, the CPU 21 is connected to a micro switch 31 that outputs an interrupt command when the housing 4 is disassembled into an upper cover 5 and a lower cover 6.

A main power supply 32 formed of a rechargeable battery or the like supplies a voltage to the CPU 21, ROM 24, RAM 26, display 8 and optical communication interface 30 when the power switch 10 is turned on. Further, the RAM 26 is supplied with a voltage from a backup power supply 34 via a backflow prevention diode 33. Reference numeral 35 in the figure is a diode for preventing the inflow of voltage from the backup power supply 34.

FIG. 3 is an exploded view of the housing of the keypad 3. As shown in the figure, the keypad 3 includes a PC board 40 between an upper cover 6 and a lower cover 7, and has four screws 41a, 41b, 41c, 41.
It is clamped and fixed from the lower cover 7 side by d. As shown in FIG. 4, the screw 41a of the power switch 10 of the screws 41a to 41d is hidden from the outside when the power switch 10 is slid to the off side, and is exposed to the outside when slid to the on side. Has become. The micro switch 31 is attached to the inner surface of the lower cover 7 as shown in FIG. 5, and when the housing 4 is assembled, the tip end 31a of the micro switch 31 is inserted through a hole formed in the PC board 40. And the protruding member 42 formed on the inner surface of the upper cover 6
When the casing 4 is disassembled, it is turned on, and turned off when the housing 4 is disassembled.

Therefore, the CPU 21 is programmed to recognize the change in the input signal when the micro switch 31 is switched from the on state to the off state as an interrupt signal and execute the interrupt processing shown in FIG. That is, as ST1, the dummy data of the keyword set in advance in the register or the like in the CPU 21 is read. Here, the dummy data may be randomly generated by a random number generation circuit incorporated in the CPU and stored in the register, or may be received from the host computer 2 and stored in the register. Next, the dummy data read as ST2 is stored in the RAM 26
The keyword is rewritten by writing in the key memory 25 in.

In a store that builds a credit card system using the keypad 3 configured as described above, the cashier receives the customer's credit card with the power switch 10 of the keypad 3 turned on and receives the card data by the card reader 9. In addition to being read, the customer is prompted to input a personal identification number consisting of four digits using the keyboard 7.
Then, the CPU 21 sends the 4-digit personal identification number entered from the keyboard 7 to the RAM 26 according to the control program in the ROM 24.
The key memory 25 is used to decrypt and encode the keyword. Then, the coded personal identification number data is transmitted to the credit terminal 1 through the optical communication interface 30 together with the card data read by the card reader 9. In the credit terminal 1, the personal identification number data and the card data from the keypad 3 are sent to the host computer 2 via the online line to inquire whether or not the transaction by the credit card is possible.

That is, in the keypad 3, power is supplied to the CPU 21, the ROM 24, the RAM 26, the display 8 and the optical communication interface 30 with the power switch 10 turned on, and normal operation is performed. On the other hand, when the power switch 10 is off, RAM26
The power from the backup power supply 34 is supplied only to the RAM, and the data in the RAM 26 is retained.

When the keypad 3 is to be disassembled, the four screws 41a that fasten and fix the upper cover 6 and the lower cover 7 together.
~ 41d needs to be removed. Therefore, the power switch 10
Must be slid on to expose the screw 41a. That is, since the power switch 10 is turned on when the housing 4 is disassembled, each element of the keypad 3 can perform a normal operation.

Also, when the power switch 10 is on, the four screws 41
When a to 41d are removed and the upper cover 6 and the lower cover 7 are disassembled, the micro switch 31 is switched from the on state to the off state, and the CPU 21 recognizes the change in the state of the micro switch 31 as an interrupt signal, and the interrupt of FIG. Perform processing. That is, the dummy data of the keyword set in advance in the register or the like is read and written in the key memory 25 in the RAM 26, the keyword is rewritten to the dummy data, and then the standby state is entered.

Therefore, according to the present embodiment, the housing 4 of the keypad 3 is
The power switch 10 must be turned on when trying to disassemble. For this reason, the CPU 21 operates in response to an interrupt command from the micro switch 31 when the screws 41a to 41d are removed and the housing 4 is disassembled into the upper cover 6 and the lower cover 7.
Rewrite the keywords stored in the key memory 25 in M26 into dummy data. Therefore, even if a third party disassembles the housing 4 and tries to read the keyword, the keyword is rewritten into dummy data at the time of disassembling it, so that there is no fear that the legitimate keyword will be read and the theft of the keyword can be prevented and the reliability can be improved. Can be improved.

The present invention is not limited to the above embodiment.
For example, although the case where the mechanical micro switch 31 is applied as the disassembly detection switch is shown in the above-described embodiment, an optical sensor or the like may be applied. Further, in the above-mentioned embodiment, the case of rewriting only the contents of the key memory 25 in the RAM 26, that is, the keyword for deciphering the personal identification number is shown when the housing 4 is disassembled, but other RAM data may be rewritten. Good. In short, the effect of the present invention is achieved by rewriting important data that may be stolen by being read in response to an interrupt command from the microswitch 31. Furthermore, in the above-described embodiment, the case where the present invention is applied to the keypad 3 is illustrated, but it is needless to say that the present invention can be applied to a data processing device that requires measures against data theft. In addition, it goes without saying that various modifications can be made without departing from the scope of the present invention.

[Effects of the Invention] As described in detail above, according to the present invention, even if data is read by the power supply from the main power source, it is possible to prevent the theft of important data such as a keyword and improve the reliability. A device can be provided.

[Brief description of drawings]

1 to 6 are diagrams showing an embodiment of the present invention, FIG. 1 is a diagram showing a schematic configuration of a credit card system using a keypad, and FIG. 2 is a block configuration diagram of the keypad. 3, FIG. 3 is an exploded view of the keypad housing, FIG. 4 is an enlarged view of a power switch portion, FIG. 5 is an enlarged view of a microswitch portion, and FIG. 6 is a flowchart showing an interrupt processing procedure in the CPU. 3 ... keypad, 4 ... housing, 5 ... top cover, 6 ...
… Bottom cover, 7 …… Keyboard, 8 …… Display, 9 ……
Card reader, 10 ... Power switch, 25 ... Key memory, 30 ... Optical communication interface, 31 ... Micro switch, 32 ... Main power supply, 34 ... Backup power supply, 41a-4
1d ... screw.

Claims (1)

[Claims] 1. A data processing device having a disassembled housing, processing input data from an input unit based on specific data stored in a storage unit built in the housing, and transmitting the processed data. In order to disassemble the case, the first
A power switch for turning on the main power source by sliding movement from the position to the second position, and a disassembly detection switch for detecting disassembly of the housing and outputting an interrupt command.
A data processing device comprising: a data rewriting unit that rewrites at least specific data stored in the storage unit in response to an interrupt command of the disassembly detection switch.