On-device random number generator

• US 20050041803A1
• Filed: 08/18/2003
• Published: 02/24/2005
• Est. Priority Date: 01/02/2003
• Status: Abandoned Application

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Dahan, Franck, Chateau, Alain
• Application Number:
  US10/643,069
• Publication Number:
  US 20050041803A1
• Time in Patent Office: Days
• US Class Current: 380/46
• CPC Class Codes: G06F 21/73 by creating or determining hardware identification, e.g. serial numbers
• CPC Class Codes: G06F 7/58 Random or pseudo-random number generators

Abstract

A random key generator circuit (10) generates a random number internal to an integrated circuit and stores the random number as a “root key” in a memory (18) on the integrated circuit. The output of the Root Key memory (18) is only accessible internal to the integrated circuit. The root key can be permanently stored in a fused memory or other memory type which is protected from erasure or reprogramming once the root key is stored.

Claims

1. Circuitry for generating a random key, comprising:

a random number generator for generating a random number implemented in an integrated circuit;

a memory internal to the integrated circuit for receiving and permanently storing the random number, said memory being accessible only internally to the integrated circuit.

2. The circuitry of claim 1 and further comprising circuitry for detecting undesirable random numbers.

3. The circuitry of claim 2 wherein said detecting circuitry comprises circuitry for detecting a ratio of “

1”

s and “

0”

s in said random number and comparing the ratio to a threshold.

4. The circuitry of claim 1 and further comprising comparison circuitry for comparing the value stored in said memory to the random number.

5. A mobile computing device comprising:

processing circuitry implemented in an integrated circuit;

a random key generator circuit implemented in said integrated circuit and coupled to said processing circuitry, comprising;

a random number generator for generating a random number;

a memory internal to the integrated circuit for receiving and permanently storing the random number, said memory being accessible only internally to the integrated circuit.

6. The mobile computing device of claim 5 wherein said random key generator further comprises circuitry for detecting undesirable random numbers.

7. The mobile computing device of claim 6 wherein said detecting circuitry comprises circuitry for detecting a ratio of “

1”

s and “

0”

s in said random number and comparing the ratio to a threshold.

8. The mobile computing device of claim 6 wherein said random key generator circuit further comprises comparison circuitry for comparing the value stored in said memory to the random number.

9. A method of generating a random key, comprising the steps of:

generating a random number in an integrated circuit;

permanently storing the random number in a memory on said integrated circuit, where said memory is accessible only internally to the integrated circuit.

10. The method of claim 9 and further comprising the steps of identifying undesirable random numbers and regenerating a new random number in response thereto.