The evolution of the car key

If time travel were possible and you visited the future, you would almost certainly want to take a car of the future for a spin. But when you reach for the car key, everyone would turn to you with confused looks on their faces and ask, "What’s a car key?” You see, the car key will almost certainly become a relic of the past.

At the Apple Worldwide Developers Conference (WWDC) held in June this year, Apple officially announced that the Car Key digital car key feature will be incorporated in iOS 14. With Car Key, drivers can use their iPhone or Apple Watch to lock, unlock, start and drive a car without a physical key, and share their virtual key with other people. The 2021 updated BMW 5 Series will be the first model to support this new feature.

According to Apple's description of Car Key, we can define the so-called digital car key as a “function” of smart phones and wearable devices through wireless communication technology. It allows drivers to forgo a physical car key and unlock and control the car with improved safety and greater convenience.

Image 1. Apple announces that it will support the Car Key digital car key feature in iOS 14 (Image source: Internet)

The history of car keys

Just as the car has undergone several evolutions over the last hundred years, so has the car key. In the beginning, you had to insert a "big crank" into the front of the car and shake it with brute force. It was hardly an elegant solution.

It was only in 1949 that Chrysler introduced car keys with a mechanical form similar to that of household keys. However, as this kind of mechanical key was too easily "cracked", anti-theft chips were implanted that required chip verification before the car could be unlocked and started.

Fast-forward to the 1990s and remote control technology came along and left its mark on the car key. The driver only needed to press a button and the car would lock or unlock with a telltale beep. This technology remains popular today.

Next came the passive keyless entry system (PKE). This meant that as long as the key was on your person, you didn't need to take it out. You just had to touch the door handle to open the door. Nor did you need to insert the key into the ignition above the driver's seat, because the vehicle starts at the press of a button.

In summary, the car key evolved from the blade-shaped mechanical key to the chip/remote control key, and finally to the PKE system, all the while making things progressively easier and more convenient for the driver. The net result is that the "car key" is becoming less and less like a key. With today's digital car keys, the very "physical existence" of the key is eliminated as the "virtual key" is built into mobile phones and other devices.

If we think about it, the virtual key will do more than lock and unlock the car door, and make starting a vehicle easier and more convenient. It will in fact provide future drivers with many new experiences. For example:

• The digitization and virtualization of keys makes the sharing and distribution of car keys easier and more efficient. Without the need to hand over physical keys, any driver who obtains a digital car key through the cloud will be authorized to unlock and use the designated vehicle. This will not only help facilitate the transfer of car usage rights between family and friends, but also aid the development of new businesses such as car rental and car sharing.
   
• The digital car key is more easily "bound" to a specific driver, and more easily and fully integrated with the vehicle and driver data. Hence car companies and service organizations will be able to provide services based on more precisely monitored and measured driver preferences.

Given that these new experiences provide an opportunity for the automotive industry to extract greater value out of their customers, it is easy to understand why everyone is rushing to adopt the digital car key.

Technologies and standards

Although the digital car key appears to be practical, a wireless communication technology that can enable "dialog" between the driver and the vehicle, complete identity authentication and other operations, and provide a safe and seamless experience, there is still a way to go before it replaces the physical key.

At present, there are several wireless technologies available to choose from in the developer's "toolbox.” The first is Bluetooth, a technology that meets the requirements of digital car key application scenarios in terms of communication distance, security and low power consumption. More importantly, Bluetooth is the most widely used of all wireless technologies. Currently, all smart phones feature Bluetooth as one of their standard specifications. In terms of cars, according to forecasts made by the Bluetooth Technology Alliance (SIG), a total of 109 million Bluetooth in-vehicle devices will be shipped by 2024, meaning that Bluetooth will be a standard feature in 87% of new vehicles produced. This also means that there will be increased demand for optional Bluetooth hardware resources that comply with vehicle specifications.

However, in the digital car key market of the future, Bluetooth will have to compete with near-field wireless communication (NFC) technology, which is already making an impact. NFC technology allows data exchange within a range of just a few centimeters and provides the "touch and open" experience. Furthermore, information is almost theft-proof as it requires verification by financial-level applications. NFC also supports drawing power from the main device, so even when the phone is in sleep mode, low battery mode or even turned off, operations such as unlocking and starting the vehicle can still occur. This is a strong selling point that differentiates it from Bluetooth. According to reports, Apple will be using NFC technology in its Car Key application.

Image 2     The NFC-based digital car key solution developed by Avnet （Image source: Avnet）

In addition to Bluetooth and NFC, there is another wireless technology that is quietly emerging in area of digital car keys – ultra-wideband (UWB) technology. UWB uses short pulses to transmit data over a wide frequency band, achieving accurate positioning by measuring time of flight (ToF) and angle of arrival of radio waves. Accuracy can reach the centimeter level, precisely detecting the user’s proximity to the car door. This feature makes it possible to use UWB to implement PKE based on data keys. As long as you carry a mobile phone or wearable device that supports UWB and a built-in digital key with you, the door will automatically unlock when you approach your car without you needing to do so much as raise your hand. Unlike other wireless technologies that use signal strength to perceive distance, UWB signals are marked with a time stamp, which can effectively prevent relay attacks from copying signals and thus greatly enhance security. Today, many car companies have activated UWB digital key programs. Apple has taken the lead by integrating UWB into iPhone 11, which was launched last year in an obvious bid to seize an early mover advantage.

 
Image 3     Application scenarios of UWB in car keys demoed by NXP and Volkswagen （Image source: NXP）

In step with the evolution of technology, standards pertaining to digital car keys are also constantly evolving. CCC (Car Connectivity Consortium) is bridging the differences between solutions provided by different manufacturers through a series of standardization processes, thus ensuring the safety of digital car keys and paving the way for the application of various technologies.

For example, CCC’s Digital Key Release specification defines how to use NFC distance restrictions and secure element applications to ensure the highest level of security for vehicle access. As UWB will be supported in the 3.0 version of the specification, CCC is currently developing a specification based on BLE combined with UWB to support the implementation of PKE digital key solutions.

According to forecast data released by Technavio, the global digital car key market will grow by 11% in 2020, achieving year-on-year growth of 1.93 million vehicles. And that is just the beginning of the revolution. The contest between various technologies, the expansion of application scenarios, and changing driver habits will all determine how the digital "key” evolves. Only when it is refined, accepted and widely adopted will the physical key truly become a relic of the past.