How to get random double value out of random byte array values?

Question

I would like to use RNGCryptoServiceProvider as my source of random numbers. As it only can output them as an array of byte values how can I convert them to 0 to 1 double value while preserving uniformity of results?

Answer 1

You can use the BitConverter.ToDouble(...) method. It takes in a byte array and will return a Double. Thre are corresponding methods for most of the other primitive types, as well as a method to go from the primitives to a byte array.

Answer 2

Use BitConverter to convert a sequence of random bytes to a Double:

byte[] random_bytes = new byte[8];  // BitConverter will expect an 8-byte array
new RNGCryptoServiceProvider().GetBytes(random_bytes);

double my_random_double = BitConverter.ToDouble(random_bytes, 0);

Answer 3

byte[] result = new byte[8];
rng.GetBytes(result);
return (double)BitConverter.ToUInt64(result,0) / ulong.MaxValue;