Quote Originally Posted by jmcilhinney View Post
Actually, now that I think about it that would probably not really work because the likelihood of getting a low number would be very small because you'd be unlikely to get all zeroes for the higher-order Bytes. What you probably ought to do is to use Random.NextDouble and then scale that value using the length of your range to select a value within it.
That would still exclude more numbers than it included as there would need to be a massive upscaling which (as we know all too well from image scaling) simply increases the gaps between possible values. Mathematics on this scale is just something for which the PC, even with BIgInteger, is simply not designed.