Phone
as a Key

• Digitalization is a megatrend – in the automotive sector, too

• Car access using a smartphone is becoming mainstream

• Huf launches digital car key with hands-free comfort

• Functions on Demand – add extras via smartphone app

The smartphone is taking over the function of the car key, combining the advantages of digital car keys with the hands-free comfort of passive access systems.

Digital car keys are becoming a matter of course

Whether with the Apple iPhone or smartphones from other manufacturers such as Samsung or Huawei, we are now used to performing a wide range of tasks with our cell phones. Smartphones have long since become much more than a means of communication. We use them to surf the Internet, exchange information via social media or news services, and in some cases also use them to control televisions and other electronic devices as well as to pay at the supermarket or the cinema. Smartphones also play a key role in cars. According to a representative survey by the IT association Bitkom, 69 percent of respondents find smartphone integration more important than the car brand when buying a car. This is because infotainment systems in modern cars automatically pair with registered smartphones when the driver gets in. It allows the driver to use hands-free phone services or play music stored on the smartphone via the car’s audio system. 

How about digital car keys using NFC?

In many cases, smartphones can also lock or unlock cars. As with payment at the supermarket checkout or gas station, NFC (near field communication) technology is used. However, NFC has one disadvantage: the smartphone must always be actively held in the hand and in front of the door handle with integrated NFC interface. This is because, as the name “Near Field Communication” suggests, data is transmitted only within the immediate vicinity.

Passive entry systems with physical car keys are quite different. These hands-free systems such as Keyless-Go from Mercedes or Comfort Access from BMW are more comfortable because the car unlocks automatically, whether the keys are in your pocket, jacket, or handbag. Yes, such systems still have a physical key; this serves as a transponder. The car can be unlocked and started without having to actively pick up and press a button on the key.

Phone as a Key: digital car key, made by Huf

Phone as a Key from Huf combines the best of both worlds. Users of this digital key system enjoy the comfort of hands-free car access and can also take advantage of the other benefits of smartphone integration, including sharing digital car keys with friends, neighbors, and family via smartphone.

Liberkee offers digital key system for more than just cars

Car rental companies and car sharing providers also benefit from these flexible authorization options. Huf has already been offering this system for digital car keys as an aftermarket solution since 2014 via its subsidiary Liberkee. In addition, the Liberkee app offers a platform for almost all applications, no matter whether mobility, housing industry, co-working spaces, or public administration. The digital key provided by Liberkee is the door opener for the Internet of Things (IoT).

Functions on Demand for new business areas

While Liberkee provides digital keys as an aftermarket solution, Huf offers Phone as a Key directly to car manufacturers, who can integrate the smart system for digital key management into their vehicles. Another advantage of this OEM solution is that with Phone as a Key, additional functions can be added on demand and over the air (OTA) via smartphone app. These digital services open up additional market potential for car manufacturers and an even more individualized customer experience thanks to numerous comfort and safety features. One example is the detection of people in the in the car. Thanks to the extremely precise positioning of the Huf UWB sensors, even the breathing movements of small children in the car can be detected. Child Presence Detection will be included in the 5-star rating in the Euro NCAP crash test from 2022. The National Highway Traffic Safety Administration (NHTSA) will also take this technology into account. These and other aspects of passenger detection will also come into play in car insurance.

• Digital key management

• Phone as a Key enables hands-free car access

Using a smartphone as a car key makes it easy to create and send new digital car keys. Huf adds the comfort of passive entry to this flexibility.

Digital car keys can be shared flexibly

Compared to a traditional car key, a digital car key has the advantage of easy and flexible management. For example, a digital car key can be created and easily deleted via smartphone. Very helpful when a vehicle is used by several people or when car access is needed at short notice.

Easy sharing of a vehicle within the family

For example, each family member with a driver’s license can have their own digital car key. Situations where a child or spouse has accidentally taken the car key and someone is now stuck at home (and with the car in the driveway, too) will not happen anymore thanks to digital car keys. Digital car keys can also be assigned with different authorizations, which offers new possibilities when sharing keys with children. For example, children can seek shelter from rain and storms in the car, but they are not allowed to start the engine thanks to the individual assignment of rights. Digital key management also offers advantages for youngsters. If youngsters with a driver’s license are not supposed to drive the car late at night or while their parents are on vacation, for example, parents can revoke the digital car key.

Another use case made possible by digital key management is the car temporarily becoming a parcel station. Car owners who are not at home and are expecting a package can send a digital key to their car to the parcel courier. The parcel courier now has the digital car key on their smartphone or other mobile device and is allowed to open the trunk, for example. The parcel courier can now place the parcel in the trunk. The other car doors remain locked, meaning that no access to the interior is possible. After they have deposited the package and closed the trunk lid, the digital car key becomes invalid and can no longer be used by the parcel courier.

The Huf Group combines digital car keys with hands-free comfort

A major advantage, but one that remains imperceptible in everyday life, is that Phone as a Key from Huf enables hands-free car access. Similar to the passive entry systems from Volkswagen (Kessy), Mercedes (Keyless-Go) or BMW (Comfort Access), the car key – or in the case of Phone as a Key, the smartphone – no longer has to be actively held in the hand to open the car and start the engine.

Many modern smartphones, starting with the Apple iPhone 12 or the latest Samsung Galaxy models, already use UWB. Smartwatches such as the Apple Watch or smart tags such as the Apple AirTags are also already equipped with UWB technology. With UWB, it is possible to locate smart devices with precision in the centimeter range.

Comfort and safety extras via smartphone app

Anyone who wants even more comfort or safety in the car can easily add these extras via a smartphone app. Car manufacturers such as Audi already offer Functions on Demand via myAudi, providing their customers with a personalized user experience. Whereas the equipment list tick boxes when buying a new car were previously the only way to equip one’s car according to how you wanted it, Functions on Demand will, in the future, also allow to personalize used cars at a later date. The Huf Phone as a Key system offers a wide range of additional extras thanks to smartphone integration and high positioning precision.

For example, the Huf Phone as Key positioning systems can recognize not only the digital car key, but also other objects and people. One example is the Child Presence Detection function. If sleeping toddlers or babies are forgotten in the car, they could suffer heat stroke or even die. Huf Phone as a Key detects even the slightest breathing movements and reacts immediately if the digital car key on the smartphone is no longer within range of the vehicle. Phone as a Key informs the car and smartphone owner via a push message, alerting them to persons in the locked car.

• Smartphone as car key with BLE, UWB, and NFC
• BLE detects proximity and saves energy
• UWB for precise positioning
• NFC for emergencies
• AUTOSAR-compatible

Signal transmission via smartphone: The Phone as a Key digital car key combines the use of BLE, UWB, and NFC to achieve high energy efficiency and precise positioning.

Combination of BLE, UWB, and NFC

With the Phone as a Key digital car key, Huf uses the three signal transmissions that are available in smartphones: Bluetooth Low Energy (BLE), Ultra Wide Band (UWB), and Near Field Communication (NFC). The different technologies complement each other ideally and play to their strengths when you approach the vehicle.

BLE detects the approach of a digital car key at an early stage

The first step is to use Bluetooth Low Energy (BLE). Satellites in the car detect the approach of the smartphone with a matching digital car key from about 30 meters away from the car. The initial exchange of data and a first check of the digital car key take place. Since the system in the vehicle is only now “woken up”, energy consumption can be kept low for both the vehicle and the smartphone. However, BLE is not sufficiently precise for exact key positioning. In major markets, the approval relevant for insurance stipulates that an engine start must be possible only if the device is clearly located inside the vehicle.

UWB for precise smartphone positioning

To achieve precise positioning, Phone as a Key uses UWB from a distance of around 10 meters to locate the device with the digital car key. Ideally, four transceiver units are located in the corners of the vehicle to enable precise positioning of the device under almost all conditions. Two additional UWB satellites are used inside the car. In this way, Phone as a Key meets the requirements for positioning precision mentioned above. The rear of the two UWB satellites in the interior can be integrated into the roof liner and thus also monitor the rear seats and the trunk. This opens up possibilities for further functions, such as passenger detection.

NFC as a fallback

Phone as a Key uses NFC as a fallback solution. NFC transceivers can be installed in door handles, the B-pillar, and in the interior, for example. If the car battery is drained, the door can still be opened thanks to NFC and a brief current pulse.

• Can be integrated into many cars and platforms
• UWB, BLE, and NFC for transmission
• Phone as a Key is AUTOSAR compliant
• Flexible and compact satellite antenna design
• Software development kit (SDK) for app developers

With experience and understanding, Huf has consistently developed the system architecture of digital key management according to market needs.

AUTOSAR compatibility as a key factor

As with all its products, Huf, as an experienced automotive supplier, has also ensured that Phone as a Key can be integrated into almost all car architectures. That is why Phone as a Key is consistently AUTOSAR compliant. AUTOSAR (AUTomotive Open System ARchitecture) is a global development partnership of car manufacturers, suppliers, and other electronics, semiconductor, and software companies founded in 2003. AUTOSAR aims to create an open and standardized software architecture for electronic control units (ECU).

Complete package of hardware and software

With Phone as a Key, OEM get a complete package: an AUTOSAR-compliant control unit, satellites for receiving UWB and BLE signals, NFC transceivers and, finally, the software algorithm that makes a major contribution to the system’s excellent positioning precision.

BLE, UWB, and NFC complement each other

Because of the long range and economical energy consumption, Phone as a Key uses BLE (Bluetooth Low Energy) for data communication and initial positioning of a device. However, this method is not precise enough for exact positioning. If the driver continues to approach the car, UWB (Ultra Wide Band) is used for centimeter-precise positioning from a distance of around ten meters.

As a fallback, access and startup are also possible using NFC (Near Field Communication). The NFC transceiver is integrated in the door handle on the driver’s door. Alternatively, the module can also be located in the B-pillar. In the interior, there is another NFC contact surface in the center console where drivers can place their smartphone.

Flexible antenna with compact design

The expertise of Huf is also reflected in the UWB and BLE satellites and the NFC transceiver. These enable more than just high positioning precision. The PCB antennas are also integrated in robust and compact housings that can be easily installed in the car.

SDK for app developers

Huf provides car manufacturer app developers with a software development kit (SDK) that allows them to easily and efficiently integrate Phone as a Key’s features into existing smartphone apps.

• AUTOSAR-compatible 
• CCC-compliant
• Security in accordance with ISO/SAE 21434
• Meets Thatcham requirements

Huf’s Phone as a Key digital car key meets all major standards on the vehicle side in terms of connectivity, compatibility, and security.

Phone as a Key is compatible with important standards

Systems for managing digital keys must be compatible with as many devices as possible and, secondly, be able to be integrated into as many vehicle architectures as possible. That is why Huf has made sure that Phone as a Key meets important standards. For example, Phone as a Key uses the common Ultra Wide Band (UWB), Bluetooth Low Energy (BLE), and Near Field Communication (NFC) methods for signal transmission and positioning, and is compliant to AUTOSAR, CCC and Thatcham.

AUTOSAR: Can be integrated into almost all vehicle architectures

Thanks to an AUTOSAR-compliant control unit, Phone as a Key integrates well with suitable vehicle architectures. AUTOSAR is a worldwide development partnership of car manufacturers and other companies in the automotive industry that have jointly developed and established an open and standardized software architecture for electronic control units (ECU).

CCC Digital Key: Standards for smartphones

Huf is a member of the (Car Connectivity Consortium), where it is working with car manufacturers, suppliers, and smartphone manufacturers on standards for communication between smartphones and cars. With “Digital Key”, CCC is developing a standard for secure digital car keys on smartphones. Central to this will be Ultra Wide Band (UWB) technology, which enables very precise and secure positioning.

The latest generations of smart devices such as smartphones, smart tags, and smartwatches already have UWB chips. Apple is considered a pioneer here with its iPhone 11 and iPhone 12, and Samsung has integrated UWB technology with the Samsung Galaxy S21+ and S21 ultra. These and other smartphones will comply with CCC standards in the future, as will Huf Phone as a Key, and will therefore be compatible.

Thatcham: Huf Phone as a Key meets anti-theft requirements

The British driving safety institute Thatcham Research stipulates that the engine may only be started when the key is inside the car. Outside the car, the interior may only be detected if the key is less than 20 centimeters from the outer skin of the car body. Phone as a Key meets these security requirements and thus offers a high level of theft protection.

ISO/SAE 21434

The “Road Vehicles – Cybersecurity Engineering” ISO/SAE 21434 standard is a standard for cyber security developed by an ISO (International Organization for Standardization) working group and SAE International (formerly the Society of Automotive Engineers). A key point of the standard is threat analysis and risk assessment.

The standard is related to the EU regulation on cyber security. The United Nations Economic Commission for Europe (UNECE) is developing a certification scheme for a cyber security management system (CSMS), which becomes mandatory for the type approval of vehicles.

• UWB prevents relay station attacks with precise positioning
• Huf Phone as a Key meets Thatcham requirements 
• Digital car key from Huf complies with ISO/SAE 21434

The smartphone as a car key must be at least as secure as traditional car keys. Phone as a Key achieves this by combining BLE and UWB.

Digital car keys more secure than radio transmission via LF

Today, car access and authorization take place almost exclusively via radio-based keys. The problem with LF technology is that savvy thieves can intercept these radio waves. With these relay station attacks, unauthorized persons gain access to the vehicle by intercepting the key signals and extending them to their own device, which they then use to fool the vehicle into believing that the matching key is present.

Bluetooth Low Energy (BLE) in conjunction with Ultra Wide Band (UWB) are capable of achieving extremely precise positioning across a large radius in comparison with current wireless technologies. UWB in particular plays to its strengths here. The signals generated use a very wide frequency range in a point-to-point positioning, generate very short time signals, and are insensitive to narrowband interference. With UWB in Phone as a Key, relay station attacks are a thing of the past. As a member of the Car Connectivity Consortium Huf is working with car manufacturers and tech giants such as Apple, Samsung, and Google toward making UWB the global standard as soon as possible.

Positioning precision is relevant for approval

Huf works on in cooperation with external partners such as NXP on a very high positioning precision, achieving very good results. This positioning precision is very important for the high approval requirements in various countries. In order for passive car access and authorization systems to receive approval relevant for insurance, there are strict specifications in many markets regarding the positioning precision of digital car key systems. Only if the system clearly detects that the smartphone is in the car may an engine start be possible.

Thatcham: Huf Phone as a Key meets anti-theft requirements

The British driving safety institute Thatcham Research regularly checks new vehicles for anti-theft protection. In addition to numerous on-board security technologies designed to prevent theft, the testers focus on systems that enable passive authorization via radio signal to open the vehicle. Important factors for a good keyless entry system are the prevention of signal extension by third parties and precise positioning. A system with very high positioning precision recognizes that the key for authorization is in the vehicle and only then starts the engine. This is also required by the Thatcham Institute. The positioning algorithms are designed to meet the highest security requirements and allow only a minimal tolerance range. Phone as a Key meets these security requirements and thus offers a high level of protection against theft.

ISO/SAE 21434: New standard for cyber security

Cyber security already plays an important role in the Phone as a Key product development process. This is why Phone as a Key complies with the new ISO/SAE 21434 standard for cyber security in the automotive sector. The standard was jointly developed by the International Organization for Standardization (ISO) and SAE International (Society of Automotive Engineers). The new regulations do not define the security loopholes in the vehicle and how to fix them, as that would be of little use due to the ever-increasing quality of hacker attacks. ISO 21434 has a significantly further-reaching impact on many processes at automotive companies. It begins with the product development process and defines clear concepts and specifications for a threat analysis and risk assessment. The standard also covers production, servicing, volume operation, and management as well as the disposal of personal data. Based on these defined frameworks and concepts, Huf communicates with its customers on a level playing field and can identify and block potential weak points in the digital world early on. This is the case, for example, with hardware and especially software components such as firmware, which is essential for reliable communication with smartphones but also offers potential risks. Then there are digital car keys, which are shared across various devices but cannot be allowed to fall into the wrong hands. The Huf Phone as a Key team has drawn up a comprehensive analysis and risk assessment, which means that it can already provide its customers with reliable estimates in line with ISO 21434.

Huf develops not only digital but also physical keys for hands-free car access with UWB, BLE, and NFC

In addition to digital car keys on smartphones, many car manufacturers would like to continue offering car buyers the physical car key. Hardly surprising, considering the handover of the car key is an important moment in the car purchase process. However, the physical car key must be compatible with the digital car key system because additional LF antennas in the vehicle are not a good solution for cost and security reasons alone. Huf has been able to reduce the power and computing requirements of the latest generation of car keys to the point where integration into an architecture with NFC, BLE, and UWB is possible. For example, a motion sensor integrated into the car key ensures that the key switches to sleep mode when it is not in use. This is how energy can be used efficiently.

• Huf has more than 100 years of experience
• Huf technology is in about 50 percent of all cars worldwide
• Huf has been working with digital car keys since 2014
• Huf is a specialist in secure car access and authorization

Huf is the specialist for car access and authorization for more than 100 years. Since 2014, Huf has offered digital car keys as a retrofit solution.

Huf: pioneer and innovator in passive vehicle access

Huf is the leading specialist in secure car access and authorization and has been the first choice and reliable partner for car manufacturers around the globe for more than 100 years. Huf supports its customers in the digital transformation with consistently up-to-date technologies in door handles, car keys, and key cards, offering suitable solutions for modern car access.

Huf has played a major role in the development of keyless entry systems

In 1989, the Mercedes SL (R129) was the first car that could be opened with infrared remote control – the remote control key was supplied by Huf. In 1999, Huf introduced the Passive Entry system. Keyless entry comfort, i.e. opening and starting the car without using the key at all, is now a widespread equipment feature with systems such as Keyless Go from Mercedes or Comfort Access from BMW. The first car door handle with NFC technology also came from Huf, making it possible to open the car with a smartphone for the first time.

Experience with digital car keys since 2014

Huf has been offering car opening, closing, and starting as well as digital key management via smartphone app as an aftermarket solution for car rental companies and car sharing providers since 2014. For this purpose, Huf founded the subsidiary Huf Secure Mobile. Since 2021, the company is called Liberkee, offering a digital key solution that also opens numerous doors and gates outside the car.

Huf is the market leader for various products in the automotive sector

Huf is the market leader for car door handles and lock sets. Around 50 percent of all cars worldwide run on Huf products. In 2020, the automotive supplier generated sales of around EUR 1 billion with 7,800 employees at 19 locations worldwide.