US 10,433,166 B2 · Cryptography using RF power measurement

Abstract

The embodiments provide a cryptography key for two communicating devices that is based on information known only to the devices. The information may only be determined by the devices. Each device determines the information without communicating key information related to the encryption key with the other. Channel characteristic reciprocity between the devices allows creation of identical keys in each device. Each device sends a signal to the other device at the same power level based on the distance between the devices. The power level may be set to result in a target receive power level at the other device. Each device samples the received signal, generates sampling results, creates a key based on the sampling results and a threshold power level, and utilizes the key. The threshold power level may be based on the target receive power level, or a median power determined from the sampling results.

Claims20

Dependent claims

A first device comprising:

a processor;
and
a memory in communication with the processor, the memory comprising executable instructions that, when executed by the processor, cause the processor to control the first device to perform functions of:
storing a first target receive power, at which a first setup signal is targeted to be received by a second device via a communication channel;
determining, from the first target receive power, a first transmission power to send the first setup signal to the second device via the communication channel;
via the communication channel, transmitting the first setup signal to the second device at the determined first transmission power;
via the communication channel, receiving a second setup signal from the second device at a second target receive power, wherein the first and second target receive powers are the same;
sampling the second setup signal to generate sampling results;
creating a key from the sampling results;
and
using the created key, encrypting or decrypting a data signal transmitted between the first and second devices via the communication channel.

8 more elements

Dependencies are inferred from the claim text.

Cryptography using RF power measurement

Life of this patent

Cryptography using RF power measurement

Life of this patent

Abstract

Claims20