using System;
using System.Security.Cryptography;
///<summary>
/// Represents a pseudo-random number generator, a device that produces random data.
///</summary>
classCryptoRandom : RandomNumberGenerator
{
privatestaticRandomNumberGenerator r;
///<summary>
/// Creates an instance of the default implementation of a cryptographic random number generator that can be used to generate random data.
///</summary>
public CryptoRandom()
 {
  r = RandomNumberGenerator.Create();
 }
 ///<summary>
 /// Fills the elements of a specified array of bytes with random numbers.
 ///</summary>
 ///<param name=”buffer”>An array of bytes to contain random numbers.</param>
 publicoverridevoid GetBytes(byte[] buffer)
 {
  r.GetBytes(buffer);
 }
 ///<summary>
 /// Returns a random number between 0.0 and 1.0.
 ///</summary>
 publicdouble NextDouble()
 {
  byte[] b = newbyte[4];
  r.GetBytes(b);
  return (double)BitConverter.ToUInt32(b, 0) / UInt32.MaxValue;
 }
 ///<summary>
 /// Returns a random number within the specified range.
 ///</summary>
 ///<param name=”minValue”>The inclusive lower bound of the random number returned.</param>
 ///<param name=”maxValue”>The exclusive upper bound of the random number returned. maxValue must be greater than or equal to minValue.</param>
 publicint Next(int minValue, int maxValue)
 {
  return (int)Math.Round(NextDouble() * (maxValue – minValue – 1)) + minValue;
 }
 ///<summary>
 /// Returns a nonnegative random number.
 ///</summary>
 publicint Next()
 {
  return Next(0, Int32.MaxValue);
 }
 ///<summary>
 /// Returns a nonnegative random number less than the specified maximum
 ///</summary>
 ///<param name=”maxValue”>The inclusive upper bound of the random number returned. maxValue must be greater than or equal 0</param>
 publicint Next(int maxValue)
 {
  return Next(0, maxValue);
 }
}