I am examining a protocol that uses CRC32 as a MAC (see note 1) the weaknesses of this method but I would nevertheless like to see if it is just weak or actually relatively easily to break. The ...
There are 100 bytes with a CRC16. However I only know the first 50. I want to change byte 5 from a known value X to another value Y, and fix up the CRC16 to be valid - without knowing bytes 50-100. ...