JP3650603B2 - Random pulse generation method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for obtaining a random pulse from an analog noise waveform generated from a noise source such as junction noise or thermal noise, which is known to generate a true random number.
More specifically, the present invention relates to a method and apparatus for obtaining a random pulse in which the generated random pulse is surely based on a true random number.
[0002]
[Prior art]
As shown in FIG. 1, the conventional random pulse focuses only on a large waveform of the analog noise waveform of the noise source and digitizes it, or rectifies it or performs full-wave rectification. . However, when removing power supply noise and unnecessary noise generated from an amplifier, a low-level signal is cut out, so the ratio of 1 and 0 of a digitized signal is not 50/50.
For this reason, it has been necessary to reprocess the fetched random number data by software or the like to bring it closer to the true random number.
[0003]
[Problems to be solved by the invention]
The present inventor also pays attention to the change in the amplitude of a plurality of small waveforms included in the large waveform of the analog noise wave of the noise source, and the amplitude of the plurality of small waveforms included from one analog noise wave. There are provided a method and an apparatus for generating random pulses without generating loss of analog noise wave characteristics of an original noise source by generating pulses corresponding to the number corresponding to.
[0004]
[Means for Solving the Problems]
When converting the analog noise wave of the noise source into digital, the inventor rectifies the analog noise wave, and then compares the change in amplitude on the time axis of the noise waveform over time by sampling synchronized with the clock. Then, the amplitude change is output as a rising waveform, no change waveform, and falling waveform, and the no change waveform is regarded as the same as the previous amplitude change, and a pulse is generated based on this. After inverting the output corresponding to the noise waveform, a random pulse generation method and apparatus for digitizing by replacing the pulse with 1 and 0 have been invented.
[0005]
Furthermore, in the present invention, the mechanism of true random number generation based on thermal noise is that the noise generated from the generation of thermal noise such as a resistor or a diode that does not flow current is inversely proportional to the frequency f because no current flows therethrough. This is pure thermal noise that does not include 1 / f noise (fluctuation). Since this pure thermal noise is based on the fact that it is completely random, unnecessary noise generated from an amplifier or power supply In order to prevent mixing, it is possible to add a configuration that accurately extracts only analog noise waves due to thermal noise.
That is, in the present invention, a signal near the zero cross can be cut off by providing a threshold.
However, when the zero cross point is shifted, the appearance rate of 1 and 0 changes, and the time that is 1 becomes longer than the time that is 0, or the time that is 0 becomes longer than the time that is 1.
[0006]
Such a phenomenon violates the condition of natural random numbers, so it is necessary to correct it. The present inventor pays attention to the fact that the time spent on rising is equal to the time spent on falling, since the analog noise waveform caused by thermal noise is an alternating current waveform including all cycles. When the analog noise wave of a noise source below a certain level is cut off and digitized, the output when there is no rise or fall (the peak or bottom of the waveform) is treated in advance as the same as the previous output. Start the inversion of the output corresponding to every other noise waveform with the cut signal (first signal hole) and end the inversion with the next cut signal (second signal hole) To digitize.
Every other full-wave rectified waveform has an inverted form of the original AC waveform, and this waveform is returned to the rising and falling edges of the original AC waveform.
As a result, it has been found that the appearance rate of 1, 0 in a specific bit which is a condition for natural random numbers can be 50%.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, any means may be used as the means for comparing the changes over time by differentiating the amplitude change in the time axis of the noise waveform over time as long as the change in the amplitude in the waveform can be detected. However, here, there is one based on sampling synchronized with a clock, and more specifically, a combination of a pair of sample and hold circuits and a comparator synchronized with a clock and a reverse phase clock is proposed.
Theoretically, the higher the clock frequency, the higher the pulse corresponding to the minute change contained in the analog noise wave, but the frequency of the analog noise wave is about 2-50 times, especially 3-10 times. More practical.
[0008]
What is the means to obtain the output of rising waveform (rising waveform), unchanged waveform (parallel waveform), falling waveform (falling waveform) along the rectified analog noise waveform? There may be.
[0009]
The cut signal (signal hole) is in front of and behind the waveform that should be negative in terms of the result of full-wave rectification of the analog noise wave on the time axis. The front signal hole is called the first signal hole, and the rear signal hole is called the second signal hole. Originally, the cut signal (signal hole) is derived from 1 / f noise (fluctuation), so this portion must not be taken into a random pulse.
You can start reversing the output corresponding to every other noise waveform at either the beginning or end of the first signal hole, or every other start or end of the second signal hole. The inversion of the output corresponding to the noise waveform may be terminated.
[0010]
The embodiments of the present invention are summarized as follows.
(1) When the analog noise wave of the noise source is converted to digital, after the analog noise wave is rectified, the change in amplitude on the time axis of the analog noise wave is shown as a rising waveform, no change waveform, and falling Random pulse generation method in which a waveform with no change is regarded as the same as the previous amplitude change, 1 and 0 pulses are generated based on this, and the output corresponding to every other noise waveform is inverted.
(2) The random pulse generation method described in 1 above, wherein the rectification is performed by full wave rectification.
(3) When the analog noise wave of a noise source below a certain level is cut off and digitized, the output of the output corresponding to every other noise waveform is started with the cut signal (first signal hole). The random pulse generation method according to 1 above, wherein digitization is performed by ending inversion at the next cut signal (second signal hole).
(4) An amplifier that amplifies a noise signal from a noise source, a rectifier that rectifies the output of the amplifier, and the output of the rectifier are compared over time by sampling synchronized with the clock, and the change in amplitude is a rising waveform, no change A waveform that is regarded as a waveform during falling and a waveform without change is regarded as the same as the change in amplitude immediately before, a pulse generation circuit that generates 1 and 0 pulses based on this, an output corresponding to every other noise waveform A random pulse generator comprising a circuit for inverting the signal and a circuit for replacing the inverted pulse with 1 and 0 for digitization.
(5) The random pulse generator as described in 4 above, wherein the rectifier is a full-wave rectifier.
(6) Compared over time by sampling synchronized with the full-wave rectifier and clock, the change in amplitude is output as a rising waveform, a no-change waveform, and a falling waveform. A threshold circuit that cuts off analog noise waves from noise sources below a certain level is provided between the circuits that are considered to be the same, and the output corresponding to every other noise waveform is the cut signal (first signal hole). The above circuit 5 has a circuit that starts reversing and ends the reversal at the next cut signal (second signal hole), and a switch circuit that stops the clock only when the signal is holed and holds the data immediately before that. The described random pulse generator.
[0011]
For the person skilled in the art, it goes without saying that various embodiments are conceivable and should not be restricted only to the examples given below.
(Example)
FIG. 2 shows a high-speed random pulse generator of the present invention.
An analog noise wave, which is an electrical signal from a noise source, is amplified by an amplifier, full-wave rectified by a full-wave rectifier, and the polarity is aligned in one direction on the positive side or negative side, and the threshold circuit does not require a certain level or less. An analog noise wave from which noise has been cut off enters sample-and-hold circuits A and B which are a pair of 1 and 2.
The pair of sample-and-hold circuits is supplied with a clock through the switch circuit 11, and the inverter circuit 3 causes the sample-and-hold circuit A on one side to receive a reverse phase clock. The AND hold circuits A and B hold the signal level of the input noise analog waveform alternately every half clock, and input the output to the comparator 4.
The comparator 4 monitors the signal level of the noise analog waveform every half clock, and outputs HIGH when the signal level rises and LOW when the signal level falls.
[0012]
However, since new data alternately enters the comparison terminal of the comparator, the comparator output continues to output HIGH, LOW, HIGH, and LOW every half clock even if there is a noise analog waveform that continues to rise.
FIG. 3A shows the output of the comparator 4.
The XOR circuit 5 repeats normal rotation and reverse rotation every half clock and digitizes it as normal ascending and descending information.
FIG. 3B shows the output of the XOR circuit 5.
Furthermore, every other noise analog waveform was the waveform that was on the negative side before full-wave rectification, and the waveform that was originally a falling waveform was inverted to a rising waveform. Need to be reversed again.
[0013]
At the time of inversion, inversion is performed at a <signal hole> where there is no signal generated by cutting out unnecessary noise below a certain level.
The signal hole pulse that is digitized by the inverter circuit 9 and enters the flip-flop circuit 10 changes the polarity for each pulse and inverts the output of the XOR 6.
The latch circuit 7 is provided in order not to output an unnecessary signal such as a glitch.
If the signal hole is longer than half a clock, signal inversion will occur during this time, so it will not work as desired. For this reason, the switch circuit 11 stops the clock only when there is a signal hole and holds the data immediately before that.
This means that the hole of the signal is quasi-erased, and the state before the signal is cut is quasi-restored.
FIG. 3C shows the output finally obtained.
As shown in FIG. 4, the method of the present invention is the same as measuring a solid noise waveform with a cut-out portion as a dotted waveform.
[0014]
[Effect of the present invention]
The present invention focuses on the change in the amplitude of a plurality of small waveforms included in a large waveform of the analog noise wave of the noise source, and corresponds to the amplitude of a plurality of small waveforms included in one analog noise wave. A random pulse to be used at high speed can be obtained without losing the characteristics of the analog noise wave of the original noise source by generating pulses corresponding to the number, and further, without including 1 / f noise (fluctuation) Thus, a random pulse generation method and apparatus capable of setting the occurrence rate of 1, 0 in a specific bit, which is a natural random condition, to 50% can be provided.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram for explaining a difference between a conventional method and a method of the present invention.
FIG. 2 is a circuit diagram of the embodiment.
FIG. 3 is a waveform diagram of pulses in (a), (b), and (c) of the circuit diagram.
FIG. 4 is a schematic diagram of waveforms measured in the present invention.
1 Sample and hold circuit A
2 Sample and hold circuit B
3 Inverter circuit 4 Comparator 5 XOR circuit 6 XOR circuit 7 Latch circuit 8 Delay circuit 9 Inverter circuit 10 Flip-flop circuit 11 Switch circuit

Claims (6)

When converting the analog noise wave of the noise source to digital, after rectifying the analog noise wave, the amplitude change in the time axis of the analog noise wave is regarded as a rising waveform, no change waveform, falling waveform A random pulse generation method in which a no-change waveform is regarded as the same as the previous amplitude change, and based on this, 1 and 0 pulses are generated, and the output corresponding to every other noise waveform is inverted. The random pulse generation method according to claim 1, wherein the rectification is performed by full-wave rectification. When the analog noise wave of the noise source below a certain level is cut off and digitized, the output corresponding to every other noise waveform is reversed with the cut signal (first signal hole), and the next The random pulse generation method according to claim 1 or 2, wherein digitization is performed by terminating inversion with the cut signal (second signal hole). The amplifier that amplifies the noise signal from the noise source, the rectifier that rectifies the output of the amplifier, and the output of the rectifier are compared over time by sampling synchronized with the clock. A circuit that considers the waveform as falling and that the waveform without change is the same as the previous amplitude change, a pulse generation circuit that generates 1 and 0 pulses based on this, and an output corresponding to every other noise waveform is inverted. A random pulse generator comprising a circuit and a circuit for digitizing the inverted pulse by replacing it with 1 and 0. The random pulse generator according to claim 4, wherein the rectifier is a full-wave rectifier. Compared over time by sampling synchronized with the full-wave rectifier and clock, the change in amplitude is output as a rising waveform, no change waveform, and falling waveform, and the no change waveform is regarded as the same as the previous amplitude change. A threshold circuit is provided between the circuits to cut off analog noise waves from noise sources below a certain level, and the output corresponding to every other noise waveform is inverted with the cut signal (first signal hole). 6. The circuit according to claim 4, further comprising: a circuit for ending inversion at the first cut signal (second signal hole); and a switch circuit for stopping the clock only when the signal hole is held and retaining the immediately preceding data. The described random pulse generator.

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