Secure modulation and demodulation

• US 8,829,984 B2
• Filed: 07/23/2012
• Issued: 09/09/2014
• Est. Priority Date: 04/07/2003
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Netlogic Microsystems Incorporated (Broadcom, Inc.)
• Inventors: Batruni, Roy G.
• Primary Examiner(s): BROWN, CHRISTOPHER J
• Application Number:
  US13/555,783
• Publication Number:
  US 20120288094A1
• Time in Patent Office: 778 Days
• Field of Search: 327/552
• US Class Current: 327/552
• CPC Class Codes: H04K 1/00 Secret communication
• CPC Class Codes: H04L 27/00 Modulated-carrier systems
• CPC Class Codes: H04L 9/0668 producing a non-linear pseudorandom sequence

Abstract

A system and method are disclosed for securely transmitting and receiving a signal. A nonlinear keying modulator is used in the transmitter to encrypt the signal using a nonlinear keying modulation technique. A nonlinear keying demodulator is used in the receiver to decrypt the signal.

Claims

1. A transmitter, comprising:

a nonlinear keying modulator comprising;

a plurality of nonlinear elements including a processor;

a plurality of linear filters; and

a combination network connecting the plurality of linear filters and the plurality of nonlinear elements including the processor;

wherein the nonlinear keying modulator is configured to encrypt a received signal using the plurality of linear filters and the plurality of nonlinear, elements;

wherein the plurality of linear filters include a plurality of feedforward filters; and

wherein the nonlinear keying modulator is adjustable varying the plurality of feedforward filters.

2. The transmitter of claim 1, wherein the nonlinear keying modulator is configured to encrypt the received signal to be decrypted by a receiver.

3. The transmitter of claim 1, wherein the nonlinear keying modulator is configured to encrypt the received signal to be decrypted by a receiver by exchanging a key.

4. The transmitter of claim 1, further comprising a linear modulator configured to linearly modulate the received signal.

5. The transmitter of claim 1, further comprising a linear modulator configured to linearly modulate the received signal, wherein the nonlinear keying modulator nonlinearly modulates the output of the linear modulator.

6. The transmitter of claim 1, further comprising a linear modulator configured to linearly modulate the received signal, wherein the linear modulator linearly modulates the output of the nonlinear keying modulator.

7. The transmitter of claim 1,

wherein the processor is a minimum-maximum processor.

8. The transmitter of claim 1,

wherein the combination network is a minimum-maximum switching matrix.

9. The transmitter of claim 1,

wherein the plurality of linear filters include a plurality of feedback filters;

and

wherein the nonlinear keying modulator is adjustable by varying the plurality of feedback filters.

10. The transmitter of claim 1,

wherein the nonlinear keying modulator is adjustable by varying a topology of the combination network.

11. The transmitter of claim 1,

wherein poles of the plurality of linear filters are inside a unit circle.

12. The transmitter of claim 1,

wherein zeros of the plurality of linear filters are inside a unit circle.

13. The transmitter of claim 1,

wherein the nonlinear keying modulator is configured by receiving a key derived from receiver configurations.

14. A transmitter, comprising:

a nonlinear keying modulator comprising;

a plurality of nonlinear elements;

a plurality of linear filters; and

a combination network connecting the plurality of linear filters and the plurality of nonlinear elements;

wherein the nonlinear keying modulator is configured to encrypt a received signal using the plurality of linear filters and the plurality of nonlinear elements;

wherein the plurality of linear filters include a number of filter coefficients; and

wherein the nonlinear keying modulator is adjustable by varying the number of filter coefficients.

15. A transmitter, comprising:

a nonlinear keying modulator comprising;

a processor; and

a plurality of linear filters coupled to the processor,

the nonlinear keying modulator configured to encrypt a received signal by;

selecting a subset of linear filters of the plurality of linear filters based on a configuration parameter;

filtering the received signal using the selected subset of linear filters; and

processing an output of the selected subset of linear filters.

16. The transmitter of claim 15, wherein the configuration parameter includes a number and type of linear filters to use for encrypting the received signal, and

wherein the type of linear filters includes a feedforward type and a feedback type.

17. The transmitter of claim 16, wherein the configuration parameter further includes a number of filter coefficients for the linear filters and a number of filter stages for the nonlinear keying modulator.

18. The transmitter of claim 15, wherein the nonlinear keying modulator further comprises a plurality of nonlinear elements, including the processor, and a combination network connecting the subset of linear filters and the plurality of nonlinear elements.