Is there any very rapid checksum generation algorithm?

Question

Searched around a bit, but I didn't really find what I wat looking for.

I have to validate about 100 byte[16384]'s every second (+ many other tasks..). The biggest problem that looks around the corner is speed.

Do you guys know any good checksum algorithm within C#.NET that is insanely fast? It does not have to be very exact, but if a single bit changes, the checksum should (usually..) change as well.

The byte's are stored in memory, so there's no IO stuff which slows it down.

Thanks!

Answer 1

If each single bit matters, the checksum algorithm would have to process each and every byte. A simple algorithm is simply adding each value and ignoring overflow:

    static unsafe uint GetChecksum(byte[] array)
    {
        unchecked
        {
            uint checksum = 0;
            fixed (byte* arrayBase = array)
            {
                byte* arrayPointer = arrayBase;
                for (int i = array.Length - 1; i >= 0; i--)
                {
                    checksum += *arrayPointer;
                    arrayPointer++;
                }
            }
            return checksum;
        }
    }

Of course you may not detect all changes and get duplicates, but it may give you an indication on how a fast algorithm performs.