System and method for dynamic tuning feedback control for random number generator

Patent metadata

Field	Value
Publication number	US-9846568-B2
Application number	US-201414275924-A
Country	US
Kind code	B2
Filing date	May 13, 2014
Priority date	May 23, 2013
Publication date	Dec 19, 2017
Grant date	Dec 19, 2017

Abstract

A random number generator includes a first circuit producing a random sequence of values, the first circuit having an adjustable input that changes the entropy of the random sequence of numbers; a second circuit receiving the random sequence of values from the first circuit and producing an output indicative of the degree of entropy of the random sequence of values, and a third circuit that adjusts the adjustable input of the first circuit in response to the output of the second circuit.

First claim

The invention claimed is:

1. A random number generator comprising
a first circuit producing a first and second random sequence of values, said circuit having a first and second adjustable input that changes the entropy of the first and second random sequence of numbers, respectively, the first circuit comprising:
a first and second oscillator producing first and second oscillating output signals, at least the second oscillator being tunable so that the frequency of said second oscillating output signal can be adjusted by signals applied to the first adjustable input, and
a first sampling circuit receiving said first and second oscillating output signals and sampling said first oscillating output signal at intervals determined by said second oscillating output signal;
a third and fourth oscillator producing third and fourth oscillating output signals, at least the fourth oscillator being tunable so that the frequency of said fourth oscillating output signal can be adjusted by signals applied to the second adjustable input, and
a second sampling circuit receiving said third and fourth oscillating output signals and sampling said third oscillating output signal at intervals determined by said fourth oscillating output signal:

the random number generator further comprising a first von Neumann de-correlator circuit receiving the first random sequence of values from the first circuit and producing a first output signal indicative of the degree of entropy of the first random sequence of values and a second output signal that changes states whenever the first random sequence of values from said first circuit is in first and second states for equal portions of a selected time period,
a second circuit that adjusts the first adjustable input of the first circuit in response to the outputs of the first von Neumann de-correlator circuit, and
a second von Neumann de-correlator circuit receiving the second random sequence of values from the first circuit and producing a first output signal indicative of the degree of entropy of the second random sequence of values and a second output signal that changes states whenever the second random sequence of values from said first circuit is in first and second states for equal portions of a selected time period, and
a third circuit that adjusts the second adjustable input of the first circuit in response to the outputs of the second von Neumann de-correlator circuit.

2. The random number generator of claim 1 in which said first, second, third and fourth oscillators are free-running from the first application of power, so that said first, second, third and fourth oscillating output signals have random phases with respect to each other.

3. The random number generator of claim 1 in which said first and second sampling circuit is a D-type flip flop having a D input receiving said first and third oscillating output signal, and a clock input receiving said second and fourth oscillating output signal.

4. The random number generator of claim 1 in which said second circuit includes a counter that counts the state changes in said first output signal of said de-correlator, and is reset each time the count reaches a predetermined threshold value.

5. The random number generator of claim 4 in which said second circuit adjusts the first adjustable input of said first circuit each time said count reaches said predetermined threshold value.

6. The circuit of claim 1 which includes a power saving control circuit for controlling operation of at least the first oscillator and the second tunable oscillator to switchably control their operation between a first normal mode of operation and a second low power mode of operation.

7. The circuit of claim 1 which includes a power saving control circuit for controlling operation of at least the first oscillator and the second tunable oscillator to switchably control their operation between a first low power mode of operation in which at least the first oscillator and the second tunable oscillator other than oscillate and a second normal mode of operation.

Assignees

• Synopsys Inc

Inventors

• Hamilton Neil Farquhar
• Hamilton Scott Andrew
• Borza Michael

Classifications

• G06F7/588 Primary

  Random number generators, i.e. based on natural stochastic processes · CPC title