CryptoApiRandomGenerator.cs :  » PDF » iTextSharp » Org » BouncyCastle » Crypto » Prng » C# / CSharp Open Source

#if !NETCF_1_0

using System;
using System.Security.Cryptography;

namespace Org.BouncyCastle.Crypto.Prng{
  /// <summary>
  /// Uses Microsoft's RNGCryptoServiceProvider
  /// </summary>
  public class CryptoApiRandomGenerator
    : IRandomGenerator
  {
    private readonly RNGCryptoServiceProvider rndProv;

    public CryptoApiRandomGenerator()
    {
      rndProv = new RNGCryptoServiceProvider();
    }

    #region IRandomGenerator Members

    public virtual void AddSeedMaterial(byte[] seed)
    {
      // We don't care about the seed
    }

    public virtual void AddSeedMaterial(long seed)
    {
      // We don't care about the seed
    }

    public virtual void NextBytes(byte[] bytes)
    {
      rndProv.GetBytes(bytes);
    }

    public virtual void NextBytes(byte[] bytes, int start, int len)
    {
      if (start < 0)
        throw new ArgumentException("Start offset cannot be negative", "start");
      if (bytes.Length < (start + len))
        throw new ArgumentException("Byte array too small for requested offset and length");

      if (bytes.Length == len && start == 0) 
      {
        NextBytes(bytes);
      }
      else 
      {
        byte[] tmpBuf = new byte[len];
        rndProv.GetBytes(tmpBuf);
        Array.Copy(tmpBuf, 0, bytes, start, len);
      }
    }

    #endregion
  }
}

#endif