How to generate a cryptographically secure Double between 0 and 1?

Question

I know how to generate a random number between 0 and 1 using the NextDouble method of the pseudo-random number generator.

var rng1 = new System.Random();
var         


        

Answer 1

Well, I would not call a 64-bit random number "cryptographically secure" - you'd want a lot more bits than that to be "cryptographically secure". But anyway, you could do something like this:

var bytes = // assume this contains 8 bytes of random numbers

long l = BitConverter.ToInt64(bytes);
double d = Math.Abs(1 / (double)l);