... for those who don't have to accommodate to an existing CRC-clone, but their task is to include one to their design: it is possible to "design" the "parameters" so, that if you feed it with a continuous stream of zeros, the resulting checksum is zero regardless of the length of the stream (in fact it's easy - just set everything to zero, in most of algos this will work).

Although a strict matematician will see no problem in this - zero is just a number as good as any other, so it's good for any checksum too - the engineer sees the gotcha - it's quite easy to have such an error in data storage or transmission, which results in such continuous stream of zeros - and that would then pass undetected.

JW