Method and device for transmitting messages in real time

A system for transmitting messages in real time between users in a closed network of a vehicle, the system comprising:

• a vehicle bus;
• at least one transmitter configured to encrypt safety-relevant real-time data of a message to be transmitted, including a transmitter ID of said transmitter, using a private key of said transmitter in order to generate an encrypted message, said transmitter configured to transmit the encrypted message, which includes the safety-relevant real-time data and the transmitter ID of said transmitter, together with an unencrypted transmitter ID of said transmitter, on said vehicle bus;
• and
• at least one receiver connected to said vehicle bus and configured to decrypt the encrypted message received through said vehicle bus using a public key of said transmitter identified by the received unencrypted transmitter ID in order to decrypt the encrypted message and obtain a decrypted Transmitter ID;
• said receiver configured to compare the decrypted transmitter ID with the unencrypted transmitter ID in order to determine whether the message has been transmitted correctly.

In a closed network of a vehicle, a receiver connected to concurrently receive an unencrypted transmitter ID and an encrypted message, which includes an encrypted transmitter ID and safety-relevant real-time data, from a transmitter, the receiver comprising:

• a memory configured to store a public key;
• a decryption unit connected to the memory to obtain a public key that is selected based on the unencrypted transmitter ID that was received by the receiver together with the encrypted message, the decryption unit configured to obtain a decrypted transmitter ID by decrypting the encrypted message using the public key that was selected based on the unencrypted transmitter ID that was received by the receiver together with the encrypted message;
• and
• a comparison unit configured to compare the unencrypted transmitter ID with the decrypted transmitter ID obtained by decrypting the encrypted message in order to determine whether the message has been transmitted correctly.