Check out example codes for "c# checksum". It will help you in understanding the concepts better.

Code Example 1

private static string GetMD5HashFromFile(string fileName)
{
	using (var md5 = MD5.Create())
	{
    	using (var stream = File.OpenRead(fileName))
        {
        	return BitConverter.ToString(md5.ComputeHash(stream)).Replace("-", string.Empty);
       	}
	}
}

Learn ReactJs, React Native from akashmittal.com