Ultra-secure communication methods and apparatus

• US 8,441,391 B2
• Filed: 05/05/2010
• Issued: 05/14/2013
• Est. Priority Date: 05/05/2010
• Status: Active Grant

• Current Assignee: Santa Mionica Semiconductor
• Original Assignee: RoundTrip, LLC
• Inventors: Karr, Lawrence J.
• Primary Examiner(s): Brainard, Timothy A
• Application Number:
  US12/774,256
• Publication Number:
  US 20110273334A1
• Time in Patent Office: 1,105 Days
• Field of Search: 342/42
• US Class Current: 342/42
• CPC Class Codes: G01S 13/825 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 13/84 for distance determination by phase measurement
• CPC Class Codes: H04K 1/06 by transmitting the information or elements thereof at unnatural speeds or in jumbled order or backwards

Abstract

A secure communication topology can be used for communications between a locator and one or more transponders to determine the location of the transponders. An example system may include a locator that is configured to transmit an interrogation signal that is encoded for receipt by one or more of the transponders. When a transponder receives and correlates the interrogation signal with an internally stored reference sequence, the transponder can transmit one or more reply transmissions at precisely determined time delay intervals. The time delay intervals are secretly known by both the locator and the transponder. The reply transmissions can each correspond to previously sampled noise signals that are also secretly known by both the transponder and the locator.

Claims

1. A method for a transponder (MT) adapted to communicate with a remote locator (RL), the method for the transponder (MT) comprising:

capturing samples of a signal transmission spectrum with a receiver in the MT;

detecting an interrogation signal from the RL when the captured samples correspond to an interrogation signal that is encoded with a specific ID Code associated with the MT; and

when the interrogation signal is detected;

synthesizing a precise carrier phase, frequency, cadence and timing for subsequent transmission from the received interrogation signal;

retrieving a first timing delay (Delay D1) and a first non-repeating noise pattern (Noise N1) for a first signal transmission;

encoding the first signal transmission with the first noise pattern (Noise N1);

wherein after the expiration of the first timing delay (Delay D1), transmitting the first signal transmission, which is encoded with the first noise pattern (Noise N1), using the precise carrier phase, frequency, cadence and timing; and

wherein retrieving the first timing delay (Delay D1) and the first noise pattern (Noise N1) comprises the steps of;

determining an index from a hash function, and

selecting the first timing delay (Delay D1) and the first noise pattern (Noise N1) using the index.

2. The method of claim 1, wherein retrieving the hash function corresponds to a cryptographic streaming hash function and wherein the crypto hash function makes the noise samples.

3. A method for a transponder (MT) adapted to communicate with a remote locator (RL), the method for the transponder (MT) comprising:

capturing samples of a signal transmission spectrum with a receiver in the MT;

detecting an interrogation signal from the RL when the captured samples correspond to an interrogation signal that is encoded with a specific ID Code associated with the MT; and

when the interrogation signal is detected;

synthesizing a precise carrier phase, frequency, cadence and timing for subsequent transmission from the received interrogation signal;

retrieving a first timing delay (Delay D1) and a first non-repeating noise pattern (Noise N1) for a first signal transmission;

encoding the first signal transmission with the first noise pattern (Noise N1);

wherein after the expiration of the first timing delay (Delay D1), transmitting the first signal transmission, which is encoded with the first noise pattern (Noise N1), using the precise carrier phase, frequency, cadence and timing; and

wherein retrieving the first timing delay (Delay D1) and the first noise pattern (Noise N1) comprises the steps of;

determining a first index from a first hash function,

determining a second index from a second hash function,

selecting the first timing delay (Delay D1) using the first index, and

selecting the first noise pattern (Noise N1) using the second index.

4. A method for a transponder (MT) adapted to communicate with a remote locator (RL), the method for the transponder (MT) comprising:

capturing samples of a signal transmission spectrum with a receiver in the MT;

detecting an interrogation signal from the RL when the captured samples correspond to an interrogation signal that is encoded with a specific ID Code associated with the MT; and

when the interrogation signal is detected;

synthesizing a precise carrier phase, frequency, cadence and timing for subsequent transmission from the received interrogation signal;

retrieving a first timing delay (Delay D1) and a first non-repeating noise pattern (Noise N1) for a first signal transmission;

encoding the first signal transmission with the first noise pattern (Noise N1);

wherein after the expiration of the first timing delay (Delay D1), transmitting the first signal transmission, which is encoded with the first noise pattern (Noise N1), using the precise carrier phase, frequency, cadence and timing; and

wherein retrieving the first noise pattern (Noise N1) comprise the steps of;

providing a predetermined seed to a streaming secure cryptographic hash function,

generating a stream of bits from the streaming secure cryptographic hash function, and

aggregating groups of bits to generate the first noise pattern (Noise N1).

5. The method of claim 4, wherein the predetermined seed is derived from one or more of a shared key, an ID code associated with the MT, a time stamp, or a date stamp.