CRYPTOGRAPHIC KEY UPDATE SYSTEM FOR UPDATING ARBITRARY LENGTH CRYPTOGRAPHIC KEYS

原文（中国語）

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.