JPH0769789B2 - Random number generator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a random number generator used in video signal processing, for example, when processing for changing the order of scanning lines is required.

2. Description of the Related Art FIG. 3 is a block diagram of a conventional random number generator.

The shift register 17 is an M-series shift register, and an initial value is set. A horizontal synchronizing signal cycle pulse (hereinafter abbreviated as H pulse) is input from the input terminal 13. The shift register 17 shifts by this H pulse, and the output result is added to the comparison circuit 18. Comparison circuit 18
Then, "L" is added to the AHD gate 16 when the input from the shift register 17 is 60 or less, and "H" when the input is more than 60.
Therefore, when the output of the shift register 17 exceeds 60, the shift register 17 is shifted through the OR gate 15. The shifted value is given to the comparison circuit 18, and when it exceeds 60, the shift register 17 is shifted again, and the shift is repeated until the output of the shift register 17 becomes 60 or less. Therefore, the output of the shift register 17 input to the latch 19 is determined by the H pulse input from the input terminal 13 or the clock from the input terminal 14 which becomes valid according to the result of the comparison circuit 18. This is latched by the latch 19 at the H pulse period, and the output terminal 20 obtains a random number sequence of 1 to 60 at the horizontal synchronizing signal period.

However, in such a configuration, when the process of repeatedly generating a random number of 1 to 60 is repeated every 60 horizontal synchronization signal periods (60H), a random number sequence is generated within each period of 60H. However, when compared in each period, the same 1-60
It is the repetition of the pattern of the random number sequence of. Therefore, when 240 lines of the effective screen of the video signal are divided into blocks of 60H and the scan line transition is performed for each block, the conventional random number generator will cause the scan line transition contents of each block to be the same. I can not get a certain degree of confidentiality.

The present invention solves the above problems and provides a random number generator capable of obtaining sufficient confidentiality.

Means for Solving the Problems In order to achieve the above object, the present invention comprises a first random number generation circuit, a second random number generation circuit, an exclusive OR circuit, a switching circuit, a protection circuit, and a comparison circuit. However, the generation cycle of the second random number generation circuit is the repetition cycle of the output pattern of the first random number circuit, and the output of the first random number generation circuit and the second
The output of the random number generation circuit of is processed by the exclusive OR circuit,
The result is detected by the protection circuit, the switching circuit outputs the output from the second random number generation circuit or the exclusive OR circuit according to the output of the protection circuit, and the comparison circuit compares the output of the switching circuit with the first output. This is to shift the random number generation circuit.

With the above-described configuration, the present invention sets the generation cycle of the second random number generation circuit to be the same as the repetition cycle of the output pattern of the first random number generation circuit, and the output of the first random number generation circuit The output of the second random number generation circuit is processed by the exclusive OR circuit, the result is detected by the protection circuit, and the switching circuit outputs the output of the second random number generation circuit or the protection circuit according to the output of the protection circuit. By comparing the output of the switching circuit with the comparison circuit and shifting the first random number generation circuit, the second random number generation circuit sequentially shifts to the first random number generation circuit without updating the initial value of the first random number generation circuit. Since a random number that changes the output random number sequence of the first random number generation circuit is given, a different random number sequence can be obtained for each cycle of repetition of the output pattern of the first random number generation circuit, and a highly confidential random number sequence can be obtained. .

Embodiment A random number generator according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a random number generator of the present invention. In FIG. 1, 1 is a horizontal synchronizing signal pulse input terminal, 2 is a clock input terminal, 5 is a shift register for random number generation that is shifted for each line, 6 is a random number generation shift register that is shifted for every 60 lines, and 7 Is an EXOR circuit that takes the exclusive OR of the bits of the shift register 5 and the shift register 6, and 8 is the detection result of the protection circuit 9 and switches the output of the EXOR circuit 7 and the output of the shift register 6 to the comparison circuit 10. It is a selector which is a switching circuit for giving. According to the comparison result of the comparison circuit 10, the clock input from the input terminal 2 is validated by the gate 3, and the shift register 5 is shifted via the gate 4. 11 is a latch that latches the output of the selector 8 that is fixed for each line,
12 is an output terminal for outputting a random number sequence.

The operation of the random number generator of the present invention configured as above will be described below. The shift register 5 is an M-sequence 7-stage shift register, and a certain value is set as an initial value. The horizontal synchronizing signal pulse input to the input terminal 1 is shown in FIG. 2 (a), and the horizontal synchronizing signal pulse is input to the input terminal 2 in FIG. 2 (b).
Indicates the clock input to.

Therefore, the shift register 5 is first shifted once in each line by the horizontal synchronizing signal pulse, and then the comparison circuit 10
As a result, if the clock input from the input terminal 2 is valid, the necessary shift is performed and the value is determined.

The shift register 5 is shifted by the horizontal synchronizing signal pulse input from the input terminal 1. On the other hand, shift register 6
The output of is shifted at the break of 60 lines. The output of the shift register 6 input to the EXOR circuit 7 has the same value during the period of 60 lines. The output of the EXOR circuit 7 is input to the selector 8 and the protection circuit 9 at the same time. Selector 8
The output of is normally the input from the EXOR circuit 7, but EX
When the outputs of the OR circuit 7 are all zero, the protection circuit 9 detects this and sets the output of the selector 8 as the value of the shift register 6. The output of the selector 8 thus obtained is the comparison circuit 10
If it is less than 60, it will output “L” to gate 3,
If it exceeds 60, output “H” to gate 3 and input terminal 2
The shift register 5 is shifted through the gate 4 by the clock input from the. In this way, the value in each line is determined, and the latch 11 outputs the random number sequence of each line to the output terminal 12. Table 1 shows a random number sequence in the first 60 lines when $ 18 is set as the load value in the shift register 5 and the output of the shift register 6 is $ 2C. Table 2 shows the output of shift register 6 after shifting in Table 1 by $ 1φ.
Shown below is a random number sequence when switching to and further shifting for 60 lines. In both tables, the order of the data is as follows. Next is the order to look at the second line. The 7 bits on the left side of each data are displayed in binary and the right side is displayed in decimal. As is clear from Tables 1 and 2, the first 60-line random number sequence is different from the next 60-line random number sequence, and a highly confidential random number sequence is obtained.

EFFECTS OF THE INVENTION As is apparent from the above embodiments, according to the present invention, the output of the shift register for sequentially generating random numbers, and
Exclusive OR for each bit with the output of the shift register for random number generation that shifts for each block of the random number sequence, and output the exclusive OR with the protection circuit and the output of the shift register for random number generation that shifts for each block By switching between and, and the shift register for generating random numbers that sequentially shifts by shifting the shift register is shifted, it is possible to obtain a highly confidential random number sequence.

[Brief description of drawings]

1 is a block diagram of a random number generator according to an embodiment of the present invention, FIG. 2 is a timing diagram of shift pulses input to the random number generator shown in FIG. 1, and FIG. 3 is a configuration of a conventional random number generator. It is a figure. 5,6 ... Shift register, 7 ... EXOR circuit, 8 ... Protection circuit, 9 ... Selector, 10 ... Comparison circuit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H04N 7/167

Claims (1)

[Claims] 1. A first random number generation circuit, a second random number generation circuit, an exclusive OR circuit, a switching circuit, a protection circuit, and a comparison circuit, wherein the generation cycle of the second random number generation circuit is: A cycle of the output pattern of the first random number generating circuit, wherein the output of the first random number generating circuit and the output of the second random number generating circuit are processed by the exclusive OR circuit,
This result is detected by the protection circuit, the switching circuit outputs the output from the second random number generating circuit or the exclusive OR circuit according to the output of the protection circuit, and the comparison circuit outputs the output of the switching circuit. And a first random number generating circuit for shifting the first random number generating circuit.