Secure, real-time based data transfer

A communication system comprising:

• at least one receiver and at least one transmitter interconnected via a field bus, the transmitter and receiver each including one of (i) a security chip and (ii) a comparable logic circuit for at least one of (i) encrypting and (ii) decrypting data telegrams, and
• a processor;
• wherein the communication system is configured to perform the real-time-based transfer of data telegrams between the transmitter and the receiver by:
• (a) providing, by the transmitter, each data telegram to be transferred from the transmitter to the receiver with an additional data index;
• (b) storing, by the receiver, each data telegram received from the transmitter in a memory, along with an associated additional data index;
• (c) transferring, by transmitter, a data telegram that has already been transferred to the receiver a second time after one of (i) a defined time interval has elapsed and (ii) a defined number of data telegrams is transferred, the data telegram that is transferred the second time having an additional signature, and the data telegram that is transferred the second time being additionally encrypted by the transmitter;
• and
• (d) performing, by the receiver, a comparison of the signed data telegram transferred a second time with a corresponding data telegram stored in the memory after receiving the signed data telegram transferred the second time to verify the transmitter;
• wherein on each occasion during which steps a) to d) are repeated, a signed data telegram transferred from the transmitter to the receiver the second time has a data index that differs from the data index of the signed data telegram that was transferred the second time in a previous run.