When an encrypted message is received, it can be easily decrypted if the offset (=counter) of the received message is known (and also the required private key of course). This allows for random access on decryption. What if the receiver somehow forgot to keep track of the counter. Can the receiver still recreate the original plaintext? Or is it required that every received encrypted text is asigned a resp. counter value upon arrival? Or is this counter passed in some way such that the receiver does not have to keep track of it, e.g. as an additional parameter.
A scenario I was thinking of is that when the receiver missed the first N blocks. He/she would then not know the current counter resulting in not being able to decrypt.