//
// System.Security.Cryptography.RNGCryptoServiceProvider
//
// Authors:
// Mark Crichton (crichton@gimp.org)
// Sebastien Pouliot (sebastien@ximian.com)
//
// (C) 2002
// Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
// "In the beginning there was Chaos,
// and within this Chaos was Power,
// Great Power without form."
// -- The Verrah Rubicon of Verena, Book One
using System.Globalization;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text;
namespace System.Security.Cryptography{
#if !NET_2_1
[ComVisible (true)]
#endif
public sealed class RNGCryptoServiceProvider : RandomNumberGenerator {
private static object _lock;
private IntPtr _handle;
static RNGCryptoServiceProvider ()
{
if (RngOpen ())
_lock = new object ();
}
public RNGCryptoServiceProvider ()
{
_handle = RngInitialize (null);
Check ();
}
#if !NET_2_1
public RNGCryptoServiceProvider (byte[] rgb)
{
_handle = RngInitialize (rgb);
Check ();
}
public RNGCryptoServiceProvider (CspParameters cspParams)
{
// CSP selection isn't supported but we still return
// random data (no exception) for compatibility
_handle = RngInitialize (null);
Check ();
}
public RNGCryptoServiceProvider (string str)
{
if (str == null)
_handle = RngInitialize (null);
else
_handle = RngInitialize (Encoding.UTF8.GetBytes (str));
Check ();
}
#endif
private void Check ()
{
if (_handle == IntPtr.Zero) {
throw new CryptographicException (
Locale.GetText ("Couldn't access random source."));
}
}
[MethodImplAttribute(MethodImplOptions.InternalCall)]
private static extern bool RngOpen ();
[MethodImplAttribute(MethodImplOptions.InternalCall)]
private static extern IntPtr RngInitialize (byte[] seed);
[MethodImplAttribute(MethodImplOptions.InternalCall)]
private static extern IntPtr RngGetBytes (IntPtr handle, byte[] data);
[MethodImplAttribute(MethodImplOptions.InternalCall)]
private static extern void RngClose (IntPtr handle);
public override void GetBytes (byte[] data)
{
if (data == null)
throw new ArgumentNullException ("data");
if (_lock == null) {
_handle = RngGetBytes (_handle, data);
} else {
// using a global handle for randomness
lock (_lock) {
_handle = RngGetBytes (_handle, data);
}
}
Check ();
}
public override void GetNonZeroBytes (byte[] data)
{
if (data == null)
throw new ArgumentNullException ("data");
byte[] random = new byte [data.Length * 2];
int i = 0;
// one pass should be enough but hey this is random ;-)
while (i < data.Length) {
_handle = RngGetBytes (_handle, random);
Check ();
for (int j=0; j < random.Length; j++) {
if (i == data.Length)
break;
if (random [j] != 0)
data [i++] = random [j];
}
}
}
~RNGCryptoServiceProvider ()
{
if (_handle != IntPtr.Zero) {
RngClose (_handle);
_handle = IntPtr.Zero;
}
}
}
}
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