From 869ccb7bcbc0850529077f13598b6e0772055bfe Mon Sep 17 00:00:00 2001
From: lidgren <lidgren@users.noreply.github.com>
Date: Sat, 11 Oct 2014 08:22:49 +0000
Subject: [PATCH] Added missing file NetCryptoProviderBase.cs

---
 .../Encryption/NetCryptoProviderBase.cs       | 76 +++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 Lidgren.Network/Encryption/NetCryptoProviderBase.cs

diff --git a/Lidgren.Network/Encryption/NetCryptoProviderBase.cs b/Lidgren.Network/Encryption/NetCryptoProviderBase.cs
new file mode 100644
index 0000000..2d6adfc
--- /dev/null
+++ b/Lidgren.Network/Encryption/NetCryptoProviderBase.cs
@@ -0,0 +1,76 @@
+using System;
+using System.IO;
+using System.Security.Cryptography;
+
+namespace Lidgren.Network
+{
+	public abstract class NetCryptoProviderBase : NetEncryption
+	{
+		protected SymmetricAlgorithm m_algorithm;
+
+		public NetCryptoProviderBase(NetPeer peer, SymmetricAlgorithm algo)
+			: base(peer)
+		{
+			m_algorithm = algo;
+			m_algorithm.GenerateKey();
+			m_algorithm.GenerateIV();
+		}
+
+		public override void SetKey(byte[] data, int offset, int count)
+		{
+			int len = m_algorithm.Key.Length;
+			var key = new byte[len];
+			for (int i = 0; i < len; i++)
+				key[i] = data[offset + (i % count)];
+			m_algorithm.Key = key;
+
+			len = m_algorithm.IV.Length;
+			key = new byte[len];
+			for (int i = 0; i < len; i++)
+				key[len - 1 - i] = data[offset + (i % count)];
+			m_algorithm.IV = key;
+		}
+
+		public override bool Encrypt(NetOutgoingMessage msg)
+		{
+			int unEncLenBits = msg.LengthBits;
+
+			var ms = new MemoryStream();
+			var cs = new CryptoStream(ms, m_algorithm.CreateEncryptor(), CryptoStreamMode.Write);
+			cs.Write(msg.m_data, 0, msg.LengthBytes);
+			cs.Close();
+
+			// get results
+			var arr = ms.ToArray();
+			ms.Close();
+
+			msg.EnsureBufferSize((arr.Length + 4) * 8);
+			msg.LengthBits = 0; // reset write pointer
+			msg.Write((uint)unEncLenBits);
+			msg.Write(arr);
+			msg.LengthBits = (arr.Length + 4) * 8;
+
+			return true;
+		}
+
+		public override bool Decrypt(NetIncomingMessage msg)
+		{
+			int unEncLenBits = (int)msg.ReadUInt32();
+
+			var ms = new MemoryStream(msg.m_data, 4, msg.LengthBytes - 4);
+			var cs = new CryptoStream(ms, m_algorithm.CreateDecryptor(), CryptoStreamMode.Read);
+
+			var result = m_peer.GetStorage(unEncLenBits);
+			cs.Read(result, 0, NetUtility.BytesToHoldBits(unEncLenBits));
+			cs.Close();
+
+			// TODO: recycle existing msg
+
+			msg.m_data = result;
+			msg.m_bitLength = unEncLenBits;
+			msg.m_readPosition = 0;
+
+			return true;
+		}
+	}
+}