// CoreUtil
// 
// Copyright (C) 2012-2014 Daiyuu Nobori. All Rights Reserved.
// Copyright (C) 2012-2014 SoftEther VPN Project at University of Tsukuba. All Rights Reserved.
// Comments: Tetsuo Sugiyama, Ph.D.
// 
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// version 2 as published by the Free Software Foundation.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License version 2
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
// 
// 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.
// 
// THE LICENSE AGREEMENT IS ATTACHED ON THE SOURCE-CODE PACKAGE
// AS "LICENSE.TXT" FILE. READ THE TEXT FILE IN ADVANCE TO USE THE SOFTWARE.
// 
// 
// THIS SOFTWARE IS DEVELOPED IN JAPAN, AND DISTRIBUTED FROM JAPAN,
// UNDER JAPANESE LAWS. YOU MUST AGREE IN ADVANCE TO USE, COPY, MODIFY,
// MERGE, PUBLISH, DISTRIBUTE, SUBLICENSE, AND/OR SELL COPIES OF THIS
// SOFTWARE, THAT ANY JURIDICAL DISPUTES WHICH ARE CONCERNED TO THIS
// SOFTWARE OR ITS CONTENTS, AGAINST US (SOFTETHER PROJECT, SOFTETHER
// CORPORATION, DAIYUU NOBORI OR OTHER SUPPLIERS), OR ANY JURIDICAL
// DISPUTES AGAINST US WHICH ARE CAUSED BY ANY KIND OF USING, COPYING,
// MODIFYING, MERGING, PUBLISHING, DISTRIBUTING, SUBLICENSING, AND/OR
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// CONTROLLED BY JAPANESE LAWS, AND YOU MUST FURTHER CONSENT TO
// EXCLUSIVE JURISDICTION AND VENUE IN THE COURTS SITTING IN TOKYO,
// JAPAN. YOU MUST WAIVE ALL DEFENSES OF LACK OF PERSONAL JURISDICTION
// AND FORUM NON CONVENIENS. PROCESS MAY BE SERVED ON EITHER PARTY IN
// THE MANNER AUTHORIZED BY APPLICABLE LAW OR COURT RULE.
// 
// USE ONLY IN JAPAN. DO NOT USE THIS SOFTWARE IN ANOTHER COUNTRY UNLESS
// YOU HAVE A CONFIRMATION THAT THIS SOFTWARE DOES NOT VIOLATE ANY
// CRIMINAL LAWS OR CIVIL RIGHTS IN THAT PARTICULAR COUNTRY. USING THIS
// SOFTWARE IN OTHER COUNTRIES IS COMPLETELY AT YOUR OWN RISK. THE
// SOFTETHER VPN PROJECT HAS DEVELOPED AND DISTRIBUTED THIS SOFTWARE TO
// COMPLY ONLY WITH THE JAPANESE LAWS AND EXISTING CIVIL RIGHTS INCLUDING
// PATENTS WHICH ARE SUBJECTS APPLY IN JAPAN. OTHER COUNTRIES' LAWS OR
// CIVIL RIGHTS ARE NONE OF OUR CONCERNS NOR RESPONSIBILITIES. WE HAVE
// NEVER INVESTIGATED ANY CRIMINAL REGULATIONS, CIVIL LAWS OR
// INTELLECTUAL PROPERTY RIGHTS INCLUDING PATENTS IN ANY OF OTHER 200+
// COUNTRIES AND TERRITORIES. BY NATURE, THERE ARE 200+ REGIONS IN THE
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// COUNTRIES' LAWS, REGULATIONS AND CIVIL RIGHTS TO MAKE THE SOFTWARE
// COMPLY WITH ALL COUNTRIES' LAWS BY THE PROJECT. EVEN IF YOU WILL BE
// SUED BY A PRIVATE ENTITY OR BE DAMAGED BY A PUBLIC SERVANT IN YOUR
// COUNTRY, THE DEVELOPERS OF THIS SOFTWARE WILL NEVER BE LIABLE TO
// RECOVER OR COMPENSATE SUCH DAMAGES, CRIMINAL OR CIVIL
// RESPONSIBILITIES. NOTE THAT THIS LINE IS NOT LICENSE RESTRICTION BUT
// JUST A STATEMENT FOR WARNING AND DISCLAIMER.
// 
// 
// SOURCE CODE CONTRIBUTION
// ------------------------
// 
// Your contribution to SoftEther VPN Project is much appreciated.
// Please send patches to us through GitHub.
// Read the SoftEther VPN Patch Acceptance Policy in advance:
// http://www.softether.org/5-download/src/9.patch
// 
// 
// DEAR SECURITY EXPERTS
// ---------------------
// 
// If you find a bug or a security vulnerability please kindly inform us
// about the problem immediately so that we can fix the security problem
// to protect a lot of users around the world as soon as possible.
// 
// Our e-mail address for security reports is:
// softether-vpn-security [at] softether.org
// 
// Please note that the above e-mail address is not a technical support
// inquiry address. If you need technical assistance, please visit
// http://www.softether.org/ and ask your question on the users forum.
// 
// Thank you for your cooperation.
// 
// 
// NO MEMORY OR RESOURCE LEAKS
// ---------------------------
// 
// The memory-leaks and resource-leaks verification under the stress
// test has been passed before release this source code.


using System;
using System.Threading;
using System.Data;
using System.Data.Sql;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using System.Text;
using System.Configuration;
using System.Collections;
using System.Collections.Generic;
using System.Security.Cryptography;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
using System.Diagnostics;
using System.Web.Mail;
using System.Net;
using System.Net.Sockets;
using System.Net.NetworkInformation;

namespace CoreUtil
{
	public class RC4 : ICloneable
	{
		uint x, y;
		uint[] state;

		public RC4(byte[] key)
		{
			state = new uint[256];

			uint i, t, u, ki, si;

			x = 0;
			y = 0;

			for (i = 0; i < 256; i++)
			{
				state[i] = i;
			}

			ki = si = 0;
			for (i = 0; i < 256; i++)
			{
				t = state[i];

				si = (si + key[ki] + t) & 0xff;
				u = state[si];
				state[si] = t;
				state[i] = u;
				if (++ki >= key.Length)
				{
					ki = 0;
				}
			}
		}

		private RC4()
		{
		}

		public object Clone()
		{
			RC4 rc4 = new RC4();

			rc4.x = this.x;
			rc4.y = this.y;
			rc4.state = (uint[])this.state.Clone();

			return rc4;
		}

		public byte[] Encrypt(byte[] src)
		{
			return Encrypt(src, src.Length);
		}
		public byte[] Encrypt(byte[] src, int len)
		{
			return Encrypt(src, 0, len);
		}
		public byte[] Encrypt(byte[] src, int offset, int len)
		{
			byte[] dst = new byte[len];

			uint x, y, sx, sy;
			x = this.x;
			y = this.y;

			int src_i = 0, dst_i = 0, end_src_i;

			for (end_src_i = src_i + len; src_i != end_src_i; src_i++, dst_i++)
			{
				x = (x + 1) & 0xff;
				sx = state[x];
				y = (sx + y) & 0xff;
				state[x] = sy = state[y];
				state[y] = sx;
				dst[dst_i] = (byte)(src[src_i + offset] ^ state[(sx + sy) & 0xff]);
			}

			this.x = x;
			this.y = y;

			return dst;
		}
		public void SkipDecrypt(int len)
		{
			SkipEncrypt(len);
		}
		public void SkipEncrypt(int len)
		{
			uint x, y, sx, sy;
			x = this.x;
			y = this.y;

			int src_i = 0, dst_i = 0, end_src_i;

			for (end_src_i = src_i + len; src_i != end_src_i; src_i++, dst_i++)
			{
				x = (x + 1) & 0xff;
				sx = state[x];
				y = (sx + y) & 0xff;
				state[x] = sy = state[y];
				state[y] = sx;
			}

			this.x = x;
			this.y = y;
		}

		public byte[] Decrypt(byte[] src)
		{
			return Decrypt(src, src.Length);
		}
		public byte[] Decrypt(byte[] src, int len)
		{
			return Decrypt(src, 0, len);
		}
		public byte[] Decrypt(byte[] src, int offset, int len)
		{
			return Encrypt(src, offset, len);
		}
	}
}

// Developed by SoftEther VPN Project at University of Tsukuba in Japan.
// Department of Computer Science has dozens of overly-enthusiastic geeks.
// Join us: http://www.tsukuba.ac.jp/english/admission/