Identification via Channels

Abstract

AbstractContrasting to Shannon’s classical coding scheme for the transmission of a message over a noisy channel in the theory of identification the decoder is not really interested in what the received message is, but he only wants to decide whether a message, which is of special interest to him, had been sent or not. If the sender knows this certain message, this is a trivial problem. He just transmits one bit over the channel, namely “Yes, my message is the same as your message” or “No, it is not”. However, if he does not know this message or if there are several receivers, each one interested in different messages, this is not possible. So there is need for a different method. There are also algorithmic problems where it is not necessary to calculate the solution, but only to check whether a certain given answer is correct. Depending on the problem, this answer might be much easier to give than finding the solution. “Easier” in this context means using less resources like channel usage, computing time or storage space.