How vehicle keyless entry security has evolved - Embedded.com

How vehicle keyless entry security has evolved

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Here is a sneak peek into vehicle access systems spanning from years-old remote keyless entry to the futuristic key as a service or KaaS.

Ever since vehicles were first invented around 3500 BC by the Babylonians, the problem of vehicle theft has been a constant reminder of the vicissitudes of ownership and property protection. Since the earliest days, concepts for vehicle protection and security have continued to evolve.

Vehicle’s mechanical locking mechanisms were invented in the 1900s, and the subsequent generations of mechanical locks became more complicated while protecting interior and engine start ignition system of the vehicle. Eventually, that led to the culmination of having one mechanical key to fit all the vehicle locks: doors, boot/trunk, hood/bonnet, and ignition.

After the arrival of the wireless key in the 1980s, innovation in wireless access control methods has scaled up and proliferated significantly over the past 40 years. This invisible operation is enabled by utilizing numerous wireless transmitters and receivers around the vehicle communicating wirelessly with a user device.

The initial concepts started in the 1980s and steadily increased the functionality and complexity with successive generations integrating different authentication systems. Later generations evolved with escalating countermeasures in wireless security technologies.

It started with the most basic wireless implementation of remote keyless entry (RKE) systems and moved to greater functionality with passive entry system (PES) and then onto the passive access and secure entry (PASE) system. It hopped from one technology to another spanning simple ASK, FSK modulation, coded frequency hopping spread spectrum in Bluetooth Low Energy (BLE) systems, and then onto ultrawideband (UWB) chirp modulation. Similarly, in the security domain, moving from simple uncoded digital to coded digital, rolling codes, and Advanced Encryption Standard (AES) implementation took this technology to higher levels of security.

Remote keyless entry (RKE)

RKE is an electronic lock that controls access to a building or vehicle without using a traditional mechanical key. The term keyless entry system originally meant a lock controlled by a keypad located at or near the driver’s door, which required entering a predetermined or self-programmed numeric code. Some systems had a hidden touch-activated keypad.

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Figure 1 Remote keyless entry controls access without using a traditional mechanical key. Source: Continental Automotive

In later generations of this device, the wireless access of the window lifter function allowed the driver the control of the windows with force limitation, an important additional safety aspect. By locking the doors with the remote-control fob or user device, the doors will be locked, and the windows and the sunroof will be closed automatically.

Passive entry system (PES)

A passive entry system (PES) enhances the remote keyless entry (RKE) system and a feature of keyless enter-n-go. This feature lets you to lock and unlock the vehicle’s door(s) without pushing the key fob lock or unlock buttons. With the key fob in the pocket or purse, just a mere touch of your fingers on the door handle unlocks and pushes open the car door in an instant.

Unlike its predecessor, remote keyless entry, the key fob responds to the door handle antennas, continuously sending out a “challenge” signal to the key fob from as far as 3 feet away. If the “challenge” is met, the fob will respond to the door lock receiver via RF signal. And vehicle authentication and unlocking occur.

Passive keyless entry (PKE)

Like PES, PKE is an automotive security system that operates automatically when the user is in proximity to the vehicle. It unlocks the door on approach or when the door handle is pulled and locks it when the user walks away or touches the car on exit.

Passive entry and passive start (PEPS)

PEPS is a secure wireless communication system that enables a driver to access the car—unlocking the car and starting the engine—without physically using a key. This system uses RF signals for authenticating the key by sending signals between the car and the key. The PEPS system uses radio waves in the low-frequency range, typically 125 kHz or 134 kHz, and radio waves in the ultra-high-frequency (UHF) range, typically sub-1 GHz signals, in a bidirectional communication to exchange unique key access codes between the key and the vehicle. Once the exchanged codes match the expected values and the key is car’s vicinity, the car allows access to the driver.

The system also measures the distance between the car and the key, determining whether the key is inside or outside the car. This information can be used to give different types of access to the driver. For example, only entry access will be granted if the key is outside the car, but the engine start function will not work.

Passive access secure entry (PASE)

With PASE, it is possible to access the vehicle and start the engine without holding the key in your hand. The vehicle’s system automatically recognizes the matching PASE key on approach, automatically starts systems, adjusts customized vehicle settings such as heating, audio, mirrors, dashboard, navigation and music, and opens the vehicle. For the driver, this means maximum ease of use as well as maximum convenience; simply get in and drive away.

Continental’s PASE system, first introduced in 1998, is undergoing continuous development. The latest innovation is the integration of UWB radio technology. Different functions are activated depending on the driver’s distance from the vehicle. Based on the type of movement or distance, the vehicle “knows” what needs to be done to make access to the car as convenient as possible for the driver.

Start with welcome light. The light is automatically switched on when the vehicle detects a valid key. Next is approach unlock. Personal vehicle settings such as seat position, climate control, and entertainment functions are activated in this zone. For walk-away locking, the doors lock automatically if the driver moves away from the vehicle. Boot/trunk opens automatically on approach without the need for additional sensors, providing increased driver convenience.

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Figure 2 In a PASE, different functions are activated depending on the driver’s distance from the vehicle. Source: Continental Automotive

While many of the above features are sometimes specific to various automotive OEMs and Tier 1 suppliers, over time, these functions have shifted to include one or more functionalities on their own. Nevertheless, the basis for the various functionalities continues to be as follows:

  1. User device access authentication to various sections of the vehicle: door, trunk, hood and other sections.
  2. User Communication on the status of the vehicle: battery, temperature, tire pressure, software updates and other states.
  3. User activated vehicle actions to switch on the headlights and air-conditioning, download software updates, roll up the windows, lock the vehicle, unlock the vehicle and other similar actions.
  4. Automated vehicle actions based on the user’s position around the vehicle like welcome lights, walk-away locking, automatic trunk opening, and even a remote driving interface for smart parking and automated valet.

Key as a service

The journey started from a simple security feature to restrict access to the vehicle interior, and then it expanded into more complex use cases of safety, security, monitoring, and actuation. Finally, it culminated in user devices wirelessly interfacing with the vehicle’s remote functionality controller.

The introduction of keyless entry and engine start functions in vehicles were followed by automatic authentication. Subsequently, that led to vehicle status monitoring and actuation, and now the next generation of wireless access systems strive to far exceed what we have in vehicles today.

Figure 3 Smartphones are now turned into a vehicle key using dedicated interface. Source: Continental Automotive

With user devices like smartphones having Internet connectivity and link to the vehicle through custom dedicated interfaces, the natural progression for a digital key is becoming a reality. The next generation of vehicle access systems is using virtual keys. Key as a service or KaaS allows vehicle manufacturers to offer drivers access to the vehicle via smartphones. Automakers are also making it easier for fleet managers and users to manage keys using flexible digital management with dynamic over-the-air (OTA) key issuance.

—Brian Fernandes is head of wireless communication R&D at the Singapore office of Continental Automotive.

>> This article was originally published on our sister site, EDN.


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