As the term itself says, one of the most important things to explore is the increase in data packet size as compare to classic CAN, CAN FD that is fulfilling the requirements in terms of data security. Longer CRC check keys are used by achieving it with adapted algorithms.
The number of data bytes that can be transmitted depending on different CRC algorithms can be used as the messages for the previous CRC formula are up to 8 data bytes as well as two enhanced algorithms that are up to 16 data bytes and even for messages, can be more than 16 data bytes.
The CAN controller can use the algorithm that is determined by the data length code so that the data security can be improved with additional suggestions that have been implemented. As the CRC is a result in CAN FD messages that always started with bits after another 5 bits as an additional bit to be included is on contrary to the CAN stuff bit rule is independent of the bit values from the previous bits. Each stuff bit has been the complementary value from the previous bit.
Source:- CAN FD