/* Transport Security Layer (TLS)
 * Copyright (c) 2003-2004 Carlos Guzman Alvarez
 * 
 * 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.
 */

using System;
using System.Security.Cryptography;

using Mono.Security.Cryptography;

namespace Mono.Security.Protocol.Tls.Handshake.Server
{
	internal class TlsClientFinished : HandshakeMessage
	{
		#region Constructors

		public TlsClientFinished(Context context, byte[] buffer)
			: base(context, HandshakeType.Finished,  buffer)
		{
		}

		#endregion

		#region Protected Methods

		protected override void ProcessAsSsl3()
		{
			bool decryptError = false;

			// Compute handshake messages hashes
			HashAlgorithm hash = new SslHandshakeHash(this.Context.MasterSecret);

			TlsStream data = new TlsStream();
			data.Write(this.Context.HandshakeMessages.ToArray());
			data.Write((int)0x434C4E54);
			
			hash.TransformFinalBlock(data.ToArray(), 0, (int)data.Length);

			data.Reset();

			byte[] clientHash	= this.ReadBytes((int)Length);			
			byte[] serverHash	= hash.Hash;
			
			// Check client prf against server prf
			if (clientHash.Length != serverHash.Length)
			{
				decryptError = true;
			}
			else
			{
				for (int i = 0; i < clientHash.Length; i++)
				{
					if (clientHash[i] != serverHash[i])
					{
						decryptError = true;
						break;
					}
				}
			}

			if (decryptError)
			{
				throw new TlsException(
					AlertDescription.DecryptError,
					"Decrypt error.");
			}
		}

		protected override void ProcessAsTls1()
		{
			byte[]			clientPRF		= this.ReadBytes((int)this.Length);
			HashAlgorithm	hash			= new MD5SHA1();
			bool			decryptError	= false;

			hash.ComputeHash(
				this.Context.HandshakeMessages.ToArray(), 
				0,
				(int)this.Context.HandshakeMessages.Length);

			byte[] serverPRF = this.Context.Cipher.PRF(
				this.Context.MasterSecret, "client finished", hash.Hash, 12);

			// Check client prf against server prf
			if (clientPRF.Length != serverPRF.Length)
			{
				decryptError = true;
			}
			else
			{
				for (int i = 0; i < serverPRF.Length; i++)
				{
					if (clientPRF[i] != serverPRF[i])
					{
						decryptError = true;
					}
				}
			}

			if (decryptError)
			{
				throw new TlsException(
					AlertDescription.DecryptError,
					"Decrypt error.");
			}
		}

		#endregion
	}
}