Vehicle Key Update Protocol for Post-Quantum Cryptographic Keys
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cryptographic key update protocols, such as the AUTomotive Open System Architecture (AUTOSAR) secure hardware extension, are inadequate for updating cryptographic keys beyond 128 bits, which is necessary for post-quantum security, as they do not provide sufficient transport security for keys with bit lengths greater than 256 bits.
Innovation Solution
A cryptographic key update system that employs an N-bit compression function and N-bit message authentication code to securely transmit and verify new cryptographic keys of arbitrary lengths greater than 256 bits, using methods like AES-COMPRESSION_FUNC and AES-CMAC, ensuring compatibility with existing systems and resistance to quantum computers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the current AUTOSAR secure hardware extension key update protocol is used, then 128-bit cryptographic keys can be provisioned and updated, but the protocol cannot support cryptographic keys with bit lengths greater than 256 bits required for post-quantum security
Solution Approach 1:
The patent changes the cryptographic parameters from fixed 128-bit keys to variable-length keys supporting 256 bits and greater. This is achieved by modifying the key update protocol to accept and process arbitrary length cryptographic keys, thereby enabling post-quantum security requirements while maintaining protocol reliability through enhanced authentication mechanisms
Solution Approach 2:
The patent segments the key update process into distinct phases: authentication phase using message authentication codes, key encryption phase using key encryption keys, and key installation phase. This segmentation allows each phase to be optimized for its specific security requirements, enabling support for longer key lengths without compromising overall protocol security
2Reliability
If cryptographic keys with bit length greater than 256 bits are implemented, then post-quantum security is achieved, but existing key update protocols lack sufficient transport security for these longer keys
Solution Approach 1:
The patent introduces intermediary cryptographic elements including message authentication codes (MACs) and key encryption keys (KEKs) that mediate the key update process. These intermediaries provide layered security where MACs authenticate messages during transmission and KEKs protect the actual cryptographic keys, enabling secure transport of long keys without requiring complete protocol redesign
Solution Approach 2:
The patent performs preliminary authentication and key establishment actions before the actual key update. Message authentication codes are computed and verified in advance, and key encryption keys are established prior to key transmission. This preliminary action ensures that even though the protocol handles longer keys, the security foundation is laid beforehand, reducing the complexity of real-time security operations
Data Source
AI summary
A method for updating arbitrary length cryptographic keys having a bit length greater than 256 bits by a cryptographic key update system includes transmitting, by a sender, a first transmission to one or more controllers that are part of a vehicle and transmitting, by the sender, a second transmission to the one or more controllers, where the second transmission is a symmetric key encryption under a key encryption key of a concatenation of a plurality of parameters and a new cryptographic key. The sender derives the key encryption key by transforming an authentication key and a bit string of constant values based on an N-bit compression function. The method includes transmitting, by the sender, a third transmission to the one or more controllers that is an N-bit message authentication code under a first message authentication code (MAC) key of a concatenation of the first transmission and the second transmission.