JPH102936A - Signal changeover device for measuring terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a signal changeover device whose security cannot be estimated even when a measuring apparatus is connected to a measuring terminal by a method wherein a switching circuit is installed and a signal for adjustment of a security circuit is output to the measuring terminal. SOLUTION: A switching circuit 3 outputs, to a measuring terminal 2, a false signal which is output by a security processing circuit 1 except when the processing circuit 1 is adjusted. When the processing circuit 1 is adjusted, a cipher signal, for switch changeover, from a terminal device (b), for adjustment, which is connected to an input terminal 4 is processed by a CPU 5. The switching circuit 3 changes over a switch by using the output signal, and it outputs a signal, for adjustment, from the processing circuit 1 to the measuring terminal 2. In this manner, when the cipher signal, for switch changeover, of the input terminal 4 is not input, a signal, for adjustment, which is required for adjusting the processing circuit 1 is not output to the measuring terminal 2. Consequently, even when a measuring apparatus is connected to the measuring terminal 2 simply, the processing-operation content of the processing circuit 1 cannot be estimated when the false signal is output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal switching device for a measuring terminal, and more particularly to a device for switching a signal to a measuring terminal for obtaining an adjusting signal when adjusting a security processing circuit. About things.

[0002]

2. Description of the Related Art Conventionally, in a processing apparatus for processing a medium on which predetermined data is recorded, such as a magnetic card or an IC card, for example, the data recorded on the medium is read and analyzed. A data processing circuit for recording new data on a medium is incorporated. This data processing circuit is subjected to security processing from the viewpoint of increasing the security of the medium so that it is not possible to know what means is being processed.

[0003] Even in the data processing circuit subjected to the security processing described above, at the time of manufacture and subsequent maintenance and inspection, it is checked whether or not the data processing device operates normally. Each component is adjusted for normal operation.

In this adjustment operation, an adjustment device such as an oscilloscope is connected to a measurement terminal exposed from a circuit board whose inside is sealed, and the output state of the measurement terminal is monitored. Done.

[0005]

As described above, the measurement terminal for operation check or adjustment is exposed in the conventional data processing circuit subjected to security processing.
When the adjustment device is inadvertently connected to the measurement terminal, there is a concern that the adjustment device may be used for security estimation of the data processing circuit.

In order to solve such a concern, it is conceivable to omit the measurement terminals or to prevent the measurement terminals from being exposed from the circuit board. New problems such as troubles in maintenance and difficulty in maintenance and inspection.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and has as its object to provide a signal for a measurement terminal which is not capable of estimating security even if the measurement terminal is exposed to the outside. A switching device is provided.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, a signal switching device for a measurement terminal according to the present invention has a measurement circuit for switching a signal to a measurement terminal from which a signal for adjusting a security circuit is output. A signal switching device for a terminal, characterized in that a switch circuit for outputting a signal for adjusting the security circuit is provided at the measurement terminal when a predetermined signal is input from the outside. A signal switching device for a measurement terminal for switching a signal to a measurement terminal from which a signal for adjusting a security circuit is output, the modulation of output to the measurement terminal when a predetermined signal is input from outside. A modulation circuit for stopping the processing and outputting a signal for adjusting the security circuit is provided. A signal switching device for a measurement terminal for switching a signal to a measurement terminal to which a signal for adjusting a security circuit is output, wherein an amplification process for outputting to the measurement terminal when a predetermined signal is input from outside. And an amplifier circuit for outputting a signal for adjusting the security circuit by changing the gain of the amplifier circuit. A signal switching device for a measurement terminal for switching a signal to a measurement terminal from which a signal for adjusting a security circuit is output, wherein the measurement terminal transmits a signal to the measurement terminal when a normal oscilloscope is connected. The output operational amplifier is set to oscillate due to the input capacitance of the oscilloscope.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a security processing device a incorporating a signal switching device for measuring terminals according to an embodiment.
FIG.

As the security processing device a, predetermined processing is performed using a medium (not shown) for storing information, such as a magnetic card or an IC card, for example, the amount data stored in the medium is processed. There is a medium processing machine that pays a purchase price for a predetermined article by using the medium processing machine. Normally, the security processing device a is processed without the contents of the processing operation being known to a third party.

The security processing circuit 1 is composed of, for example, an arithmetic processing circuit such as a CPU for processing the above-mentioned processing operation contents without being known to a third party.

In the figure, reference numeral 2 denotes a measuring terminal which is provided so as to be exposed from the security device a. The measurement terminal 2 is provided with an adjustment at the time of manufacturing the security device a and an adjustment at the time of maintenance (hereinafter, referred to as adjustment including maintenance and inspection).
And a measuring device (not shown) such as an oscilloscope capable of detecting the output state of the measuring terminal.

In FIG. 1, reference numeral 3 denotes a switch circuit which operates as indicated by a solid line to output a pseudo signal output from the security circuit 1 to the measuring terminal 2 except when the security circuit 1 is adjusted. Is configured.

In the switch circuit 3, when the security circuit 1 is adjusted, an adjustment terminal b is connected to an input terminal 4 provided to be exposed from the security processing device. When a switching signal is input, the switching circuit is operated by an output signal from the CPU 5 which processes the input signal, as shown by a dashed line, so that an adjustment signal can be output from the security circuit 1 to the measurement terminal 2. ing.

As described above, an adjustment signal necessary for adjusting the security circuit 1 is not output to the measurement terminal 2 unless a switch switching signal is input to the input terminal 4. Even if the device is connected, only a pseudo signal is output, so that it is impossible to estimate the processing operation content of the security circuit 1 and the security of the security circuit 1 can be enhanced.

When the signal input to the input terminal 4 is an encryption signal, the security effect can be further enhanced. Further, when the CPU 5 outputs a switch switching signal only when special program data for switch switching is supplied from the input terminal 4, the security effect can be further enhanced.

FIG. 2 shows another embodiment of the present invention, in which a modulation circuit 6 is provided in place of the switch circuit 3 of FIG.

When there is no signal from the CPU 5, that is, when the modulation stop signal is not input to the input terminal 4, the modulation circuit 6 modulates the adjustment signal from the security processing circuit 1 and outputs it to the measurement terminal 2. I am trying to do it.

Therefore, when no signal is input to the input terminal 4, the modulated adjustment signal is output to the measurement terminal 2, so that it is difficult to estimate the processing operation of the security circuit 1 and to maintain security. it can.

FIG. 3 shows still another embodiment, in which a variable gain type amplifier (PGA) 7 is provided in place of the modulation circuit of FIG.

When there is no signal from the CPU 5, that is, when no signal is input to the input terminal 4, the PGA 7 is measured in a state where the adjustment signal from the security processing circuit 1 is saturated or in a state where security cannot be estimated. Terminal 2
Output to

Therefore, in a state where no signal is input to the input terminal 4, a signal whose security cannot be estimated is output to the measuring terminal 2, so that it is difficult to estimate the processing operation content of the security circuit 1 and to maintain security. Can be.

FIG. 4 shows still another embodiment, in which the input terminal 4 and the CPU 5 in each of the above figures are omitted, and an adjustment signal of the security circuit 1 is supplied to an operational amplifier (O / O).
It is configured to output to the measurement terminal 2 via a P amplifier 8.

The OP amplifier 8 oscillates when a normal oscilloscope is connected to the measuring terminal 2 and is set so that security estimation cannot be performed. Then, in order to obtain an adjustment signal from the measurement terminal 2, an adjustment signal is obtained only when an oscilloscope is connected to the measurement terminal 2 via a probe having a predetermined low input capacitance.

[0025]

The signal switching device for the measuring terminal according to the present invention is provided with a switch circuit for outputting a signal for adjusting the security circuit to the measuring terminal when a predetermined signal is input from the outside. Simply connecting the measuring device to the measuring terminal does not enable security estimation, and can enhance the security effect. When a predetermined signal is input from the outside, a modulation circuit that stops the modulation process of the output to the measurement terminal and outputs a signal for adjusting the security circuit is provided. Even if connected, security cannot be estimated, and the security effect can be enhanced. When a predetermined signal is input from the outside, an amplification circuit that outputs a signal for adjusting the security circuit by changing the gain of the amplification process that is output to the measurement terminal is provided. Can not be estimated even if it is connected, and the security effect can be enhanced. The measurement terminal is set so that when an ordinary oscilloscope is connected, the operational amplifier that is outputting a signal to that measurement terminal oscillates due to the input capacitance of the oscilloscope. However, security cannot be estimated, and the security effect can be enhanced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a signal switching device for a measurement terminal according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a signal switching device for a measurement terminal according to another embodiment of the present invention.

FIG. 3 is a schematic diagram of a signal switching device for a measurement terminal according to still another embodiment of the present invention.

FIG. 4 is a schematic diagram of a signal switching device for a measurement terminal according to another embodiment of the present invention.

[Explanation of symbols]

 a Security processing device b Adjustment terminal b 'Oscilloscope 1 Security circuit 2 Measurement terminal 3 Switch circuit 4 Input terminal 5 CPU 6 Modulation circuit 7 PGA 8 OP amplifier

Claims (4)

[Claims] 1. A signal switching device for a measuring terminal for switching a signal to a measuring terminal to which a signal for adjusting a security circuit is output, wherein the measuring terminal is connected to a predetermined terminal when a predetermined signal is inputted from outside. And a switch circuit for outputting a signal for adjusting the security circuit. 2. A signal switching device for a measurement terminal for switching a signal to a measurement terminal to which a signal for adjusting a security circuit is output, wherein the measurement terminal is connected to a predetermined signal from outside. A signal switching device for a measurement terminal, comprising a modulation circuit for outputting a signal for adjusting the security circuit by stopping a modulation process of an output to the measurement terminal. 3. A signal switching device for a measuring terminal for switching a signal to a measuring terminal to which a signal for adjusting a security circuit is output, wherein the measuring terminal is connected to a predetermined terminal when a predetermined signal is inputted from outside. A signal switching device for a measurement terminal, comprising: an amplification circuit for outputting a signal for adjusting the security circuit by changing a gain of an amplification process to be output to the measurement terminal. 4. A signal switching device for a measurement terminal for switching a signal to a measurement terminal from which a signal for adjusting a security circuit is output, wherein the measurement terminal is connected to a normal oscilloscope when the oscilloscope is connected. A signal switching device for a measurement terminal, wherein the operational amplifier outputting a signal to the measurement terminal is set to oscillate due to an input capacitance of the oscilloscope.