How can I generate random Int64 and UInt64 values using the Random class in C#?
Here you go, this uses the crytpo services (not the Random class), which is (theoretically) a better RNG then the Random class. You could easily make this an extension of Random or make your own Random class where the RNGCryptoServiceProvider is a class-level object.
using System.Security.Cryptography;
public static Int64 NextInt64()
{
var bytes = new byte[sizeof(Int64)];
RNGCryptoServiceProvider Gen = new RNGCryptoServiceProvider();
Gen.GetBytes(bytes);
return BitConverter.ToInt64(bytes , 0);
}