Pseudo-random number generation based on periodic sampling of one or more linear feedback shift registers

• US 8,229,108 B2
• Filed: 08/15/2003
• Issued: 07/24/2012
• Est. Priority Date: 08/15/2003
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Wan, Wade Keith, Chen, Sherman (Xuemin)
• Primary Examiner(s): Cervetti, David Garcia
• Application Number:
  US10/642,318
• Publication Number:
  US 20050036607A1
• Time in Patent Office: 3,266 Days
• Field of Search: 380/265, 380/28, 380/46, 708/252, 708/250
• US Class Current: 380/28
• CPC Class Codes: H04L 9/0668 producing a non-linear pseudorandom sequence

Abstract

One or more methods and systems of generating pseudo-random numbers that are used as encryption keys in cryptographic applications are presented. In one embodiment, a method of generating pseudo-random numbers is performed by sampling output sequences of a linear feedback shift register with a specified periodicity. In one embodiment, the generating of pseudo-random numbers using linear feedback shift registers is accomplished by periodically switching between iterative outputs generated by multiple linear feedback shift registers. In one embodiment, a method of encrypting a pseudo-random number generated by a linear feedback shift register comprises using a nonlinear operator. In one embodiment, a method of further encrypting a pseudo-random number is accomplished by using a hashing function whose initial value varies over time by way of a function operating on one or more variables. In one embodiment, an apparatus for generating pseudo-random numbers using linear feedback shift registers comprises a digital hardware.

Claims

1. A method of generating pseudo-random numbers using linear feedback shift registers in which the correlation between successive pseudo-random numbers is reduced, said method comprising periodically switching between iterative outputs generated by at least a first linear feedback shift register and iterative outputs generated by at least a second linear feedback shift register.

2. The method of claim 1 wherein said pseudo-random numbers are generated with a period equal to the sum of each of the individual linear feedback shift register periods.

3. The method of claim 2 wherein said pseudo-random numbers are generated with a period equal to the sum of each of the individual linear feedback shift register periods.

4. The method of claim 2 wherein said pseudo-random numbers are generated with a period equal to the sum of each of the individual linear feedback shift register periods.

5. The method of claim 1 further comprising:

receiving said pseudo-random number generated from said linear feedback shift register; and

varying the initial value of said hashing function over time by way of a function operating on one or more variables.

6. The method of claim 5 wherein said one or more variables comprises the configuration of feedback taps associated with said linear feedback shift register.

7. A method of further encrypting a pseudo-random number generated from a linear feedback shift register by using a hashing function comprising:

receiving said pseudo-random number generated from said linear feedback shift register; and

varying the initial value of said hashing function over time by way of a function operating on one or more variables.