Systems and methods for encrypting communication between vehicles

Patent metadata

Field	Value
Publication number	US-11122425-B2
Application number	US-201916510097-A
Country	US
Kind code	B2
Filing date	Jul 12, 2019
Priority date	Jul 13, 2018
Publication date	Sep 14, 2021
Grant date	Sep 14, 2021

Abstract

A physical layer secret key generation scheme exploiting randomness of the road surface and driving behavior is described herein. A symmetric key generation scheme can be implemented in any existing V2V visible light communication. By analyzing and simulating numerous samples taken from NGSIM vehicle trajectory data, the natural driving behavior and road surface roughness can be exploited as a source of randomness to generate symmetric cryptographic security keys.

First claim

What is claimed is:

1. A method of generating a set of at least two identical encryption keys, for encrypting data across a communications channel shared by at least two vehicles, wherein the encryption keys are generated independently by each vehicle, wherein the encryption keys are generated from a stochastic process of the communications channel shared by the vehicles, wherein the stochastic process is observable to all of the vehicles and caused by road conditions and driving behavior, said method comprising:
a. coordinating a common time for the vehicles to begin sampling the stochastic process ( 101 );
b. for all of the vehicles, simultaneously sampling a plural number of sample points of the stochastic process ( 102 ), wherein the number of sample points is identical for all of the vehicles, wherein each sample point has a corresponding index;
c. for each vehicle, for each sample in the plurality of samples ( 103 ) thus sampled, quantizing the sample point using a quantization rule ( 104 ), wherein the quantization rule is the same for all vehicles, wherein the quantized point is a key bit of the encryption key, wherein the quantization rule determines if the key bit is a one “1”, a “0”, or invalid, wherein if the sample point is a “1” or a “0”, it is a valid sample point, wherein the indices corresponding to the valid sample points comprise a plurality of valid indices ( 105 ), wherein the key bits of all of the valid sample points together comprise a plurality of key bits ( 109 );
d. for each vehicle, sharing the plurality of valid indices with all other vehicles;
e. for each vehicle, comparing the pluralities of valid indices for all of the other vehicles, selecting only the valid indices shared by all vehicles ( 107 ), and determining a plurality of shared valid indices ( 108 ) that are common to all of the at least two vehicles, and
f. for each vehicle, selecting the plurality of key bits corresponding to the shared valid index values ( 110 ), wherein the plurality of key bits thus selected comprises the encryption key ( 111 ),
wherein because the stochastic process is observable to all of the vehicles, and the process used to generate the plurality of key bits is common to all vehicles, the encryption keys thus generated are identical.

2. The method of claim 1 , wherein the communications channel is a vehicle to vehicle visible light communication channel, wherein a pre-defined visible light signal is simultaneously transmitted between the at least two vehicles, wherein the signal is symmetrically affected by road conditions and driving behavior in a manner observable to the vehicles, wherein the stochastic process comprises fluctuations in a signal strength of the visible light signal transmitted between the vehicles.

3. The method of claim 1 , wherein the signal is an RF signal, wherein the stochastic process comprises fluctuations of RF signal strength caused by road conditions and driving behavior.

4. The method of claim 1 , wherein the signal is visible light of headlights from one vehicle to the other, wherein the stochastic process comprises fluctuations of headlight light brightness due to the road conditions and driving behavior.

5. The method of claim 1 , wherein the quantization rule comprises an upper and a lower threshold, wherein the key bit is a 1 if the sample value is greater than the upper threshold, wherein the key bit is a 0 if the sample is below the lower threshold, wherein the sample is invalid otherwise.

6. The method of claim 5 , wherein the threshold values vary depending on the index corresponding to the sample point.

7. A system ( 200 ) for sending encrypted messages between a first vehicle and a second vehicle, wherein the first vehicle and the second vehicle are symmetrically affected by a stochastic nature of road conditions and driving behavior, wherein a pre-defined probe signal is sent between the first vehicle and the second vehicle which is symmetrically affected by road conditions and driving behavior, wherein received probe signals are used to generate symmetric encryption keys, the system comprising:
a. the first vehicle ( 201 ), capable of transmitting a first light signal ( 210 );
b. a first transceiver ( 202 ) disposed on the first vehicle ( 201 );
c. a first sensor ( 203 ) disposed on the first vehicle ( 201 ), capable of sensing a second light signal ( 211 ) transmitted by the second vehicle ( 205 );
d. a first processor ( 204 ), operatively connected to the first transceiver ( 202 ) and the first sensor ( 203 ), executing computer readable instructions comprising:
i. instructions for sending messages ( 209 ) to the second vehicle via the first transceiver, and for receiving messages from the second vehicle via the first transceiver;
ii. instructions for sending a pre-defined probe signal to the second vehicle;
iii. instructions for receiving the pre-defined probe signal from the second vehicle;
iv. instructions for sampling a fixed number of sample points from the pre-defined probe signal at fixed intervals, producing a first plurality of sample points ( 212 ), wherein each sample point has an index value;
v. instructions for quantizing the first plurality of sample points, wherein the quantized sample point is a “1” or a “0”, or invalid, wherein the quantized sample points that are “1” or “0” are valid, wherein the index values of the valid sample points comprise a first plurality of valid index values, wherein the valid quantized sample points comprise a first plurality of key bits corresponding to the first plurality of valid index values,
vi. instructions for transmitting the first plurality of valid index values to the second vehicle ( 214 ),
vii. instructions for receiving a second plurality of valid index values from the second vehicle ( 214 ),
viii. instructions for comparing the first plurality of valid index values to the second plurality of valid index values, and for determining a plurality of shared valid index values;
ix. instructions for selecting the plurality of key bits corresponding to the plurality of shared valid index values, wherein the plurality of key bits thus selected comprises a first encryption key ( 215 );
x. instructions for encrypting a first message using the first encryption key;
xi. instructions for transmitting the encrypted first message to the second vehicle;
xii. instructions for receiving an encrypted second message from the second vehicle; and
xiii. instructions for decrypting the encrypted second message using the first encryption key;

e. the second vehicle ( 205 ), capable of transmitting the second light signal ( 211 );
f. a second transceiver ( 206 ), disposed on the second vehicle;
g. a second sensor ( 207 ), disposed on the second vehicle, capable of sensing the first light signal ( 210 ) of the first vehicle;
h. the second processor ( 208 ), operatively connected to the second transceiver and the second sensor, capable of executing computer readable instructions comprising:
i. instructions for sending messages ( 209 ) to the first vehicle via the transceiver, and receiving messages from the second vehicle via the transceiver;
ii. instructions for sending the pre-defined probe signal to the first vehicle;
iii. instructions for receiving the pre-defined probe signal from the first vehicle;
iv. instructions for sampling a fixed number of sample points from the received probe signal at fixed intervals, producing a second plurality of sample points ( 213 ), wherein each sample point has an index value;
v. instructions for quantizing the second plurality of sample points, wherein the quantized sample point is a “1” or a “0”, or invalid, wherein the quantized sample points that are “1” or “0” are valid, wherein the index values of the valid sample po

Assignees

• Univ California

Inventors

• Zaman Imam Uz
• Lopez Anthony Bahadir
• Al Faruque Mohammad Abdullah
• Boyraz Ozdal

Classifications

• H04L2209/80

  Wireless · CPC title

• H04W12/041

  Key generation or derivation · CPC title

• H04W12/03 Primary

  Protecting confidentiality, e.g. by encryption · CPC title

• H04L9/0866

  involving user or device identifiers, e.g. serial number, physical or biometrical information, DNA, hand-signature or measurable physical characteristics · CPC title

• H04W4/46

  for vehicle-to-vehicle communication [V2V] · CPC title