>I don't use it. I'm approaching this from the POV that if it's commonly used across the net, someone else has already implemented the class, and you don't have to reinvent the wheel.

Yes, this is what it is. That class is a .NET class of the commonly used CRC32 standard. There is probably just something I didn't type correctly when I normalized it as it works ok for everything which is pretty much under 5 MB. But, over that, it gives negative values.