Random number generation system with ring oscillators

• US 8,583,711 B2
• Filed: 12/02/2009
• Issued: 11/12/2013
• Est. Priority Date: 12/02/2009
• Status: Expired due to Fees

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Hars, Laszlo
• Primary Examiner(s): Kinkead, Arnold
• Assistant Examiner(s): Tan, Richard
• Application Number:
  US12/629,274
• Publication Number:
  US 20110128081A1
• Time in Patent Office: 1,441 Days
• Field of Search: 331/57, 331/78, 708250-256
• US Class Current: 708/250
• CPC Class Codes: G06F 7/588 Random number generators, i.e. based on natural stochastic processes

Abstract

A random number generation system comprising one or more ring oscillators configured to generate entropy due to accumulated phase drift. A random number generator can include a ring oscillator configured to switch between a first state in which a signal of the ring oscillator oscillates between logic levels, and a second state in which the signal at least partially settles to one of the logic levels. The random number generator can also include a counter configured to measure a count of pulses of the signal and a whitener mechanism configured to receive the signal from the ring oscillator, latch a logic level of the signal from the ring oscillator, latch the count of pulses from the counter, and generate a random number based on the logic level and the count of pulses. Corresponding methods may also be performed.

Claims

1. A random number generation system comprising:

a ring oscillator configured to switch between a first state in which a signal of the ring oscillator oscillates between logic levels, and a second state in which the signal at least partially settles to one of the logic levels;

a counter configured to measure a count of pulses of the signal; and

a mechanism configured to receive the signal from the ring oscillator, latch a logic level of the signal from the ring oscillator, latch the count of pulses from the counter, and generate a non-deterministic random number based on the logic level and the count of pulses.

2. The random number generation system of claim 1, wherein the ring oscillator comprises:

a plurality of inverters; and

a gate operably coupled between a first and a second of the plurality of inverters, the gate being configured to switch the ring oscillator between the first state and the second state.

3. The random number generation system of claim 2, wherein the gate comprises an exclusive OR gate.

4. The random number generation system of claim 2, and further comprising a signal generator, wherein a first input of the gate is operably coupled to the signal generator.

5. The random number generation system of claim 1, wherein the ring oscillator further comprises a multiplexer having a plurality of circuits configured to adjust a pulse frequency of the signal.

6. The random number generation system of claim 1, wherein the counter is operably coupled to the ring oscillator and configured to count pulses of the signal while the ring oscillator is in the second state.

7. A random number generation system comprising:

a signal generator;

a plurality of inverters;

a gate comprising a first input operably coupled to the signal generator, a second input operably coupled to a first of the inverters, and an output operably coupled to a second of the inverters, wherein the gate is configured to function as an inverter when a signal from the signal generator is at a first logic level and as a buffer when the signal is at a second logic level;

a counter operably coupled to at least one of the plurality of inverters or the output of the gate; and

a whitener configured to;

receive an output signal from one of the plurality of inverters;

latch a logic level of the output signal;

latch a count of pulses from the counter; and

combine the logic level and the count of pulses to generate a non-deterministic random number.

8. The random number generation system of claim 7, wherein the gate comprises an exclusive OR gate.

9. The random number generation system of claim 7, further comprising a multiplexer having a plurality of circuits, the multiplexer operably coupled to at least one of the plurality of inverters or to the output of the gate.

10. A method comprising:

generating phase drift in an oscillating signal;

latching the oscillating signal to at least partially settle to a logic level;

latching a count of pulses that corresponds to a time required for the latched signal to settle to the logic level; and

combining the logic level and the count of pulses to generate a non-deterministic random number.

11. The method of claim 10, wherein generating the phase drift in the oscillating signal comprises transmitting the oscillating signal through a plurality of inverters.

12. The method of claim 11, wherein latching the oscillating signal comprises switching a gate, which is operably coupled to at least one of the plurality of inverters, from functioning as an inverter to functioning as a buffer.

13. A random number generation system comprising:

an oscillator comprising;

a gate chain comprising;

a first plurality of inverters; and

a gate having a first input operably coupled to a first of the first plurality of inverters, a second input, and an output, wherein a second of the first plurality of inverters is operably coupled to the output of the gate;

a feedback network comprising a second plurality of inverters, wherein the second input of the gate is operably coupled to one of the second plurality of inverters;

a counter operably coupled to an oscillator output from the oscillator and configured to measure a count of pulses of the oscillator output; and

a circuit configured to;

receive the oscillator output;

latch a logic level of the oscillator output;

latch the count of pulses from the counter; and

generate a non-deterministic random number by combining the logic level and the count of pulses.

14. The random number generation system of claim 13, wherein a second of the second plurality of inverters is operably coupled to the output of the gate.

15. The random number generation system of claim 13, wherein the gate comprises an exclusive OR gate.

16. The random number generation system of claim 13, wherein the gate is a first gate, and wherein the random number generation system further comprises:

a signal generator; and

a second gate having a first input operably coupled to the signal generator, a second input operably coupled to the output of the second of the first plurality of inverters, and an output, wherein the second input of the first gate is operably coupled to the output of the second gate.

17. The random number generation system of claim 16, wherein the second gate comprises a NAND gate.

18. The random number generation system of claim 13, and further comprising a plurality of XOR gates, wherein at least a portion of the XOR gates are operably coupled between the output of the gate and the at least one of the first plurality of inverters.