CCC 3.0 Vehicle Keyless Entry System Implementation System Architecture

With the development of various wireless connection technologies and the release of the Car Connectivity Consortium Digital Key Release 3.0 (CCC3.0) specification, the standard for smartphones to become fully digital car keys has been determined.

This article will gradually learn the CCC3.0 standard for vehicle digital keys, and will gradually and incompletely implement the CCC3.0 demo based on the evaluation board and SDK of the NXP BLE chip KW38/KW45, as well as UWB and Secure Element in subsequent studies.

1. CCC3.0 Standard vs. CCC2.0 Standard

In the CCC2.0 standard, NFC near-field contactless communication technology is used to provide a channel for data interaction between the mobile phone digital key and the vehicle's security module (Secure Element), so as to realize processes such as owner authentication (Owner Pairing), standard transmission (Stand Transaction), and fast transmission (Fast Transaction).

As a supplement to the CCC2.0 standard, the CCC3.0 standard is mandatory to retain support for NFC technology as a backup solution compatible with the CCC2.0 standard. In addition, the following functions are added:

Add BLE wireless communication technology. BLE can replace NFC as the channel for data interaction of security modules. It also undertakes the negotiation of UWB security ranging session parameters, provides UWB first security ranging time synchronization mechanism, and can provide RKE remote control, start/lock engine and other functions.

Adding UWB security ranging function and adding keyless entry and location awareness functions by implementing UWB connection can bring a better user-friendly experience.

CCC3.0 extends end-to-end security from the secure element of the mobile phone to the secure element of the car through BLE. By adding UWB wireless connection technology, a secure ranging session is established. The ranging key is derived from the
digital key securely stored in the Secure Element. The ranging key has a limited life cycle, which shortens the time window available to attackers and provides secure ranging.

2. Digital Key System Architecture

The system architecture provided in CCC3.0 is shown in Figure 1. In addition to the owner key end (mobile phone or physical key), vehicle end, friend key device, owner key OEM server, car manufacturer OEM server, friend key OEM server, and key tracking server, a relay server is also added. It is designed to provide a standard interface for sharing key services for different key OEM manufacturers.

In the architecture of Figure 1, the CCC 3.0 standard specifies the links of the standard interface, which are the solid line parts in the figure, while the private interface or common interface links shown by the dotted line are outside the standard. The following are the functions of each link:

Link (1): This link provides a secure communication channel between the vehicle and the OEM server and is fully controlled by the OEM.

Link (2): This link provides a secure communication channel between the vehicle owner's device and the vehicle owner's OEM server.

Links (3), (4), (11), (12): Standard links specified in the CCC3.0 standard, used for communication between the vehicle and the device to perform functions such as owner pairing, vehicle locking/unlocking, and engine starting. You can choose to implement these functions through links (3) and (4) in the case of NFC connection; or through links (11) and (12) in the case of BLE/UWB connection.

Links (9) and (10): provide proprietary interfaces between the owner's mobile device and the friend's device and the car OEM server, respectively, to provide communication with the car manufacturer's OEM server.

Links (2), (6), (7), (8), (13), (14): Through these links, the car owner's mobile device can share the digital key with the friend's device. The mobile phone OEM server is responsible for managing the life cycle of the digital key applet and updating the necessary certificates in the car owner's/friend's mobile phone through (2)/(7); in addition, (13) and (14) can also be used to interact through the relay server. The communication links (6) and (8) between the car manufacturer's OEM server and the (car owner's/friend's) mobile phone OEM server are used to exchange server certificates, key sharing, key tracking, key termination and notification.

Link (5): The key tracking server is an optional server. Link (5) provides a connection from the OEM server to the key tracking server to manage user accounts and track all verified digital keys of registered vehicles, thereby protecting the privacy of stored information.

3. Digital Key System Demo

The CCC3.0 standard digital key system architecture is a complete digital key ecosystem. Building a complete one requires cooperation from multiple parties and consumes a lot of resources. Therefore, the demo implemented by KW45 simplifies the functions to achieve the purpose of learning by reference to the demo. The KW45 SDK provides a BLE routine of CCC3.0, which only implements the basic functions of BLE. The demo will implement richer functions on the routine.

3.1 Vehicle-side hardware structure

The KW45 evaluation board as a master/slave node is connected to the UWB (NCJ29D5) evaluation board via SPI and controls an external LED as an output to display the vehicle status in real time. The SE node KW45 is connected to the SE (SE051 or NCJ38) evaluation board via SPI. The nodes are connected via the CAN bus.

3.1.1 The master node provides the following functions:

1). Implement the data path BLE <-> CAN-FD <-> SE, as the transfer of SE interaction data, to achieve the security information interaction between the vehicle-side SE and the mobile phone digital key, so as to support processes such as owner authentication

2). Configure UWB and start safe distance measurement

3).

Realize UWB time synchronization with the mobile phone, and start UWB ranging from the node through CAN bus control

4). Collect UWB ranging information from the node and forward it to the mobile phone via BLE

3.1.2 The slave node provides the following functions:

1). Configure UWB and start safe distance measurement

2). Receive the master node to control and start UWB

3). The ranging results are transmitted to the master node via CAN

3.1.3SE nodes provide the following functions:

BLE <-> CAN-FD <-> SE data path, SE endpoint data

3.2 Mobile phone display interface

The mobile phone implements owner authentication, UWB secure ranging session parameter negotiation, BLE to UWB time synchronization mechanism, and displays the mobile phone location distance information through the distance information sent back by the vehicle.