GPSKey: GPS based Secret Key Establishment for Intra-Vehicle Environment
Edwin Yang, Song Fang · 2022
In order to overcome such limitations, context-based pairing schemes, where they extract secret key from common observations (e.g., visual channel [29], ambient audio [9], [14], timing of detected events [11], wireless signal strength [12], [33] and wireless channel interference [19], [22]) without requiring human interactions are proposed.However, these schemes present two shortcomings: (1) The surrounding environment may not consistently provide enough randomness for effective key generations.For example, [11] requires a user to generate additional events to reduce pairing time.(2) Some channels may not available in a normal vehicle.For example, audio signals in a vehicle can be easily interfered with by noises and vibrations.Recent research efforts propose context-based pairing schemes for vehicular environments [6], [16].They focus on a fact that devices located in the same vehicle experience highly similar movement, which can be captured by inertial measurement unit (IMU) sensors (e.g., accelerometer, gyroscope, and magnetometer).For example, [16] derives a key from the vertical acceleration (perpendicular to lateral and longitudinal acceleration) of a vehicle, which is affected by vehicle type and road condition.[6] employs three different sensors, where a vehicle's lateral and longitudinal accelerations are captured by an accelerometer, a gyroscope is utilized for measuring the vehicle's turns, and a barometer monitors altitude changes.However, these schemes present two limitations: (1) IMU sensor data can be easily disturbed by device movement, thus may not be robust or provide a consistent performance when the user uses or wear the device during key establishment.(2) IMU sensor data are considered insensitive on modern mobile devices, where any mobile applications can access them without specific privilege [21], [35].In this paper, we utilize a vehicle's movement pattern in GPS data to derive secret keys.The key idea is that two GPSenabled devices in the same vehicle may observe the same vehicle movement with highly similar accuracy.The vehicle movement is determined by a driver's pedal control, which contains randomness from the surrounding traffic environment.Each device extracts secret bits from the observed vehicle velocity when the vehicle is moving.While the devices may get slightly different binary bit sequences due to observation errors, they perform reconciliation to agree on the same key.We implement a prototype of the proposed key establishment scheme and perform real-world experiments to quantify its performance.Extensive experimental results show that the legitimate devices can establish a 128-bit key in a 71-Abstract-With the advent of the in-vehicle infotainment (IVI) systems (e.g., Android Automotive) and other portable devices (e.g., smartphones) that may be brought into a vehicle, it becomes crucial to establish a secure channel between the vehicle and an in-vehicle device or between two in-vehicle devices.Traditional pairing schemes are tedious, as they require user interaction (e.g., manually typing in a passcode or bringing the two devices close to each other).Modern vehicles, together with smartphones and many emerging Internet-of-things (IoT) devices (e.g., dashcam) are often equipped with built-in Global Positioning System (GPS) receivers.In this paper, we propose a GPS-based Key establishment technique, called GPSKey, by leveraging the inherent randomness of vehicle movement.Specifically, vehicle movement changes with road ground conditions, traffic situations, and pedal operations.It thus may have rich randomness.Meanwhile, two invehicle GPS receivers can observe the same vehicle movement and exploit it for key establishment without requiring user interaction.We implement a prototype of GPSKey on top of off-the-shelf devices.Experimental results show that legitimate devices in the same vehicle require 1.18-minute of driving on average to establish a 128-bit key.Meanwhile, the attacker who follows or leads the victim's vehicle is unable to infer the key.