Vehicle Transponder Authentication Using Adaptive Bit-Length Encryption
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Solution Overview
Problem
Existing wireless authentication methods between transponder devices and vehicle reader units are complex to implement and have long authentication checking periods due to the complexity of encryption algorithms, especially in passive transponder devices, which limits the range and efficiency of communication.
Innovation Solution
A simplified encryption and decryption method is introduced, allowing for adaptable data length in bits for random numbers and encrypted functions, using a DES encryption algorithm and configuring the transponder device to transmit data packets of specific lengths, such as 32, 64, or 128 bits, to expedite authentication while maintaining sufficient security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex encryption algorithms are used for authentication, then security is improved, but authentication checking period increases and device complexity increases
Solution Approach 1:
The authentication data is segmented into multiple portions that are transmitted in separate time slots. The first portion is transmitted in a first time slot and the second portion in a second time slot, allowing parallel processing and reducing the overall authentication time while maintaining security through distributed encryption operations
Solution Approach 2:
Encryption operations are performed in advance on different portions of authentication data before transmission. The reader unit encrypts the first portion and the transponder encrypts the second portion beforehand, so that during the actual authentication process, the verification can proceed more quickly without performing complex real-time encryption
2Reliability
If more authentication data bits are transmitted, then security is improved, but transmission time increases and communication range is limited
Solution Approach 1:
The system dynamically adapts the number of bits used for authentication data transmission based on the communication range between reader and transponder. When the distance is short, more bits can be transmitted for higher security; when the distance is long, fewer bits are used to maintain acceptable authentication speed, creating a dynamic balance between security and speed
Solution Approach 2:
The authentication process uses only the necessary portion of available data bits based on security requirements and communication conditions. Instead of always transmitting maximum bits, the system transmits an optimized number of bits that provides sufficient security for the given scenario, reducing unnecessary transmission time
3Ease of operation
If transponder device is placed further from vehicle, then accessibility is improved, but signal strength decreases and authentication reliability deteriorates
Solution Approach 1:
The system dynamically adjusts authentication parameters based on detected communication range. When the transponder is detected at a greater distance, the system adapts by using authentication methods that are more robust to signal degradation, maintaining reliability while allowing greater accessibility
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method reduces the complexity of encryption processes, allowing for quicker authentication and authorization of vehicle functions, while maintaining a balance between security and efficiency, even at shorter communication ranges.
Implementation Method 1
Wireless data transmission or communication via electromagnetic signals between a transponder device and a reader unit placed in a vehicle
Data Source
AI summary
The method enables authentication data to be communicated and checked between a transponder device (1) and a reader unit (2) of a vehicle in order to authorize access to the vehicle. The device includes a logic circuit (11), a non-volatile memory (13), an encryption and/or decryption circuit (12) and a first transmission and reception module (14, 16) of data signals (SD). The reader unit includes a microprocessor unit (21), a memory (22), a random number generator (24) and a second module (23, 25) for transmitting and receiving data signals (SD). A random number (RN1) generated in the reader unit is transmitted with a first encrypted function obtained using the random number and a secret key. The transponder device receives the random number and the first encrypted function. A new first encrypted function is calculated in the transponder device using a secret key identical to the secret key of the reader unit. This new first function is compared with the first received encrypted function. A second encrypted function is also calculated in the transponder device in order to be transmitted to the reader unit solely if the new first encrypted function is equal to the first received encrypted function. The validity of the second encrypted function is checked in the reader unit in order to authorize access to the vehicle. The number of bits of the random number, of the first and second encrypted functions can be configured in the transponder device and/or in the reader unit with a determined length.