This question can be classified as “theoretical computer science”. Sorry if this is the wrong place to ask, I warmly encourage you to suggest me more appropriate places.

Suppose to send a message M and let R be the CRC obtained using a generating polynomial G.
Thus, we send the “redundant” message
M' = [M R].

Now, suppose that during the transmission, the message arrives corrupted by errors to receiver. Let’s call it M'', with M'' != M'.

Suppose now that the receiver classifies M'' as “good”, i.e. the CRC algorithms gives 0 as remainder when “dividing” M'' by G.

Even thought I know that this is a very rare situation, what would a communication system do in such a situation? Is the received “doomed” to use the collected “trash data”? How can this affect the quality of the communication?

Thanks in advance!