Progress on tutorial, gap tweaking (water flows faster from room to room), UPnP error messages, input keys in array, underwater aiming tweaking, tons of misc stuff commit more often ffs

Lidgren.Network/Encryption/INetEncryption.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Generic;
+
+namespace Lidgren.Network
+{
+	/// <summary>
+	/// Interface for an encryption algorithm
+	/// </summary>
+	public interface INetEncryption
+	{
+		/// <summary>
+		/// Encrypt an outgoing message in place
+		/// </summary>
+		bool Encrypt(NetOutgoingMessage msg);
+
+		/// <summary>
+		/// Decrypt an incoming message in place
+		/// </summary>
+		bool Decrypt(NetIncomingMessage msg);
+	}
+}

Lidgren.Network/Encryption/NetAESEncryption.cs

@@ -0,0 +1,172 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Security.Cryptography;
+using System.Text;
+
+namespace Lidgren.Network
+{
+	/// <summary>
+	/// AES encryption
+	/// </summary>
+	public class NetAESEncryption : INetEncryption
+	{
+		private readonly byte[] m_key;
+		private readonly byte[] m_iv;
+		private readonly int m_bitSize;
+		private static readonly List<int> m_keysizes;
+		private static readonly List<int> m_blocksizes;
+
+		static NetAESEncryption()
+		{
+#if !IOS && !__ANDROID__
+			AesCryptoServiceProvider aes = new AesCryptoServiceProvider();
+			List<int> temp = new List<int>();
+			foreach (KeySizes keysize in aes.LegalKeySizes)
+			{
+				for (int i = keysize.MinSize; i <= keysize.MaxSize; i += keysize.SkipSize)
+				{
+					if (!temp.Contains(i))
+						temp.Add(i);
+					if (i == keysize.MaxSize)
+						break;
+				}
+			}
+			m_keysizes = temp;
+			temp = new List<int>();
+			foreach (KeySizes keysize in aes.LegalBlockSizes)
+			{
+				for (int i = keysize.MinSize; i <= keysize.MaxSize; i += keysize.SkipSize)
+				{
+
+					if (!temp.Contains(i))
+						temp.Add(i);
+					if (i == keysize.MaxSize)
+						break;
+				}
+			}
+			m_blocksizes = temp;
+#endif
+		}
+
+		/// <summary>
+		/// NetAESEncryption constructor
+		/// </summary>
+		public NetAESEncryption(byte[] key, byte[] iv)
+		{
+			if (!m_keysizes.Contains(key.Length * 8))
+				throw new NetException(string.Format("Not a valid key size. (Valid values are: {0})", NetUtility.MakeCommaDelimitedList(m_keysizes)));
+
+			if (!m_blocksizes.Contains(iv.Length * 8))
+				throw new NetException(string.Format("Not a valid iv size. (Valid values are: {0})", NetUtility.MakeCommaDelimitedList(m_blocksizes)));
+
+			m_key = key;
+			m_iv = iv;
+			m_bitSize = m_key.Length * 8;
+		}
+
+		/// <summary>
+		/// NetAESEncryption constructor
+		/// </summary>
+		public NetAESEncryption(string key, int bitsize)
+		{
+			if (!m_keysizes.Contains(bitsize))
+				throw new NetException(string.Format("Not a valid key size. (Valid values are: {0})", NetUtility.MakeCommaDelimitedList(m_keysizes)));
+
+			byte[] entropy = Encoding.UTF32.GetBytes(key);
+			// I know hardcoding salts is bad, but in this case I think it is acceptable.
+			HMACSHA512 hmacsha512 = new HMACSHA512(Convert.FromBase64String("i88NEiez3c50bHqr3YGasDc4p8jRrxJAaiRiqixpvp4XNAStP5YNoC2fXnWkURtkha6M8yY901Gj07IRVIRyGL=="));
+			hmacsha512.Initialize();
+			for (int i = 0; i < 1000; i++)
+			{
+				entropy = hmacsha512.ComputeHash(entropy);
+			}
+			int keylen = bitsize / 8;
+			m_key = new byte[keylen];
+			Buffer.BlockCopy(entropy, 0, m_key, 0, keylen);
+			m_iv = new byte[m_blocksizes[0] / 8];
+
+			Buffer.BlockCopy(entropy, entropy.Length - m_iv.Length - 1, m_iv, 0, m_iv.Length);
+			m_bitSize = bitsize;
+		}
+
+		/// <summary>
+		/// NetAESEncryption constructor
+		/// </summary>
+		public NetAESEncryption(string key)
+			: this(key, m_keysizes[0])
+		{
+		}
+
+		/// <summary>
+		/// Encrypt outgoing message
+		/// </summary>
+		public bool Encrypt(NetOutgoingMessage msg)
+		{
+#if !IOS && !__ANDROID__
+			try
+			{
+				// nested usings are fun!
+				using (AesCryptoServiceProvider aesCryptoServiceProvider = new AesCryptoServiceProvider { KeySize = m_bitSize, Mode = CipherMode.CBC })
+				{
+					using (ICryptoTransform cryptoTransform = aesCryptoServiceProvider.CreateEncryptor(m_key, m_iv))
+					{
+						using (MemoryStream memoryStream = new MemoryStream())
+						{
+							using (CryptoStream cryptoStream = new CryptoStream(memoryStream, cryptoTransform, CryptoStreamMode.Write))
+							{
+								cryptoStream.Write(msg.m_data, 0, msg.m_data.Length);
+							}
+							msg.m_data = memoryStream.ToArray();
+						}
+					}
+				}
+
+			}
+			catch
+			{
+				return false;
+			}
+			return true;
+#else
+			return false;
+#endif
+		}
+
+		/// <summary>
+		/// Decrypt incoming message
+		/// </summary>
+		public bool Decrypt(NetIncomingMessage msg)
+		{
+#if !IOS && !__ANDROID__
+			try
+			{
+				// nested usings are fun!
+				using (AesCryptoServiceProvider aesCryptoServiceProvider = new AesCryptoServiceProvider { KeySize = m_bitSize, Mode = CipherMode.CBC })
+				{
+					using (ICryptoTransform cryptoTransform = aesCryptoServiceProvider.CreateDecryptor(m_key, m_iv))
+					{
+						using (MemoryStream memoryStream = new MemoryStream())
+						{
+							using (CryptoStream cryptoStream = new CryptoStream(memoryStream, cryptoTransform,
+																			 CryptoStreamMode.Write))
+							{
+								cryptoStream.Write(msg.m_data, 0, msg.m_data.Length);
+							}
+							msg.m_data = memoryStream.ToArray();
+						}
+					}
+				}
+
+			}
+			catch
+			{
+				return false;
+			}
+			return true;
+#else
+			return false;
+#endif
+		}
+	}
+}

Lidgren.Network/Encryption/NetBlockEncryptionBase.cs

@@ -0,0 +1,88 @@
+using System;
+using System.Collections.Generic;
+
+namespace Lidgren.Network
+{
+	/// <summary>
+	/// Base for a non-threadsafe encryption class
+	/// </summary>
+	public abstract class NetBlockEncryptionBase : INetEncryption
+	{
+		// temporary space for one block to avoid reallocating every time
+		private byte[] m_tmp;
+
+		/// <summary>
+		/// Block size in bytes for this cipher
+		/// </summary>
+		public abstract int BlockSize { get; }
+
+		/// <summary>
+		/// NetBlockEncryptionBase constructor
+		/// </summary>
+		public NetBlockEncryptionBase()
+		{
+			m_tmp = new byte[BlockSize];
+		}
+
+		/// <summary>
+		/// Encrypt am outgoing message with this algorithm; no writing can be done to the message after encryption, or message will be corrupted
+		/// </summary>
+		public bool Encrypt(NetOutgoingMessage msg)
+		{
+			int payloadBitLength = msg.LengthBits;
+			int numBytes = msg.LengthBytes;
+			int blockSize = BlockSize;
+			int numBlocks = (int)Math.Ceiling((double)numBytes / (double)blockSize);
+			int dstSize = numBlocks * blockSize;
+
+			msg.EnsureBufferSize(dstSize * 8 + (4 * 8)); // add 4 bytes for payload length at end
+			msg.LengthBits = dstSize * 8; // length will automatically adjust +4 bytes when payload length is written
+
+			for(int i=0;i<numBlocks;i++)
+			{
+				EncryptBlock(msg.m_data, (i * blockSize), m_tmp);
+				Buffer.BlockCopy(m_tmp, 0, msg.m_data, (i * blockSize), m_tmp.Length);
+			}
+
+			// add true payload length last
+			msg.Write((UInt32)payloadBitLength);
+
+			return true;
+		}
+
+		/// <summary>
+		/// Decrypt an incoming message encrypted with corresponding Encrypt
+		/// </summary>
+		/// <param name="msg">message to decrypt</param>
+		/// <returns>true if successful; false if failed</returns>
+		public bool Decrypt(NetIncomingMessage msg)
+		{
+			int numEncryptedBytes = msg.LengthBytes - 4; // last 4 bytes is true bit length
+			int blockSize = BlockSize;
+			int numBlocks = numEncryptedBytes / blockSize;
+			if (numBlocks * blockSize != numEncryptedBytes)
+				return false;
+
+			for (int i = 0; i < numBlocks; i++)
+			{
+				DecryptBlock(msg.m_data, (i * blockSize), m_tmp);
+				Buffer.BlockCopy(m_tmp, 0, msg.m_data, (i * blockSize), m_tmp.Length);
+			}
+
+			// read 32 bits of true payload length
+			uint realSize = NetBitWriter.ReadUInt32(msg.m_data, 32, (numEncryptedBytes * 8));
+			msg.m_bitLength = (int)realSize;
+			return true;
+		}
+
+		/// <summary>
+		/// Encrypt a block of bytes
+		/// </summary>
+		protected abstract void EncryptBlock(byte[] source, int sourceOffset, byte[] destination);
+
+		/// <summary>
+		/// Decrypt a block of bytes
+		/// </summary>
+		protected abstract void DecryptBlock(byte[] source, int sourceOffset, byte[] destination);
+	}
+}

Lidgren.Network/Encryption/NetDESEncryption.cs

@@ -0,0 +1,164 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Security.Cryptography;
+using System.Text;
+
+namespace Lidgren.Network
+{
+	/// <summary>
+	/// DES encryption
+	/// </summary>
+	public class NetDESEncryption : INetEncryption
+	{
+		private readonly byte[] m_key;
+		private readonly byte[] m_iv;
+		private readonly int m_bitSize;
+		private static readonly List<int> m_keysizes;
+		private static readonly List<int> m_blocksizes;
+
+		static NetDESEncryption()
+		{
+
+			DESCryptoServiceProvider des = new DESCryptoServiceProvider();
+			List<int> temp = new List<int>();
+			foreach (KeySizes keysize in des.LegalKeySizes)
+			{
+				for (int i = keysize.MinSize; i <= keysize.MaxSize; i += keysize.SkipSize)
+				{
+					if (!temp.Contains(i))
+						temp.Add(i);
+					if (i == keysize.MaxSize)
+						break;
+				}
+			}
+			m_keysizes = temp;
+			temp = new List<int>();
+			foreach (KeySizes keysize in des.LegalBlockSizes)
+			{
+				for (int i = keysize.MinSize; i <= keysize.MaxSize; i += keysize.SkipSize)
+				{
+
+					if (!temp.Contains(i))
+						temp.Add(i);
+					if (i == keysize.MaxSize)
+						break;
+				}
+			}
+			m_blocksizes = temp;
+		}
+
+		/// <summary>
+		/// NetDESEncryption constructor
+		/// </summary>
+		public NetDESEncryption(byte[] key, byte[] iv)
+		{
+			if (!m_keysizes.Contains(key.Length * 8))
+				throw new NetException(string.Format("Not a valid key size. (Valid values are: {0})", NetUtility.MakeCommaDelimitedList(m_keysizes)));
+
+			if (!m_blocksizes.Contains(iv.Length * 8))
+				throw new NetException(string.Format("Not a valid iv size. (Valid values are: {0})",  NetUtility.MakeCommaDelimitedList(m_blocksizes)));
+
+			m_key = key;
+			m_iv = iv;
+			m_bitSize = m_key.Length * 8;
+		}
+
+		/// <summary>
+		/// NetDESEncryption constructor
+		/// </summary>
+		public NetDESEncryption(string key, int bitsize)
+		{
+			if (!m_keysizes.Contains(bitsize))
+				throw new NetException(string.Format("Not a valid key size. (Valid values are: {0})", NetUtility.MakeCommaDelimitedList(m_keysizes)));
+
+			byte[] entropy = Encoding.UTF32.GetBytes(key);
+			// I know hardcoding salts is bad, but in this case I think it is acceptable.
+			HMACSHA512 hmacsha512 = new HMACSHA512(Convert.FromBase64String("i88NEiez3c50bHqr3YGasDc4p8jRrxJAaiRiqixpvp4XNAStP5YNoC2fXnWkURtkha6M8yY901Gj07IRVIRyGL=="));
+			hmacsha512.Initialize();
+			for (int i = 0; i < 1000; i++)
+			{
+				entropy = hmacsha512.ComputeHash(entropy);
+			}
+			int keylen = bitsize / 8;
+			m_key = new byte[keylen];
+			Buffer.BlockCopy(entropy, 0, m_key, 0, keylen);
+			m_iv = new byte[m_blocksizes[0] / 8];
+
+			Buffer.BlockCopy(entropy, entropy.Length - m_iv.Length - 1, m_iv, 0, m_iv.Length);
+			m_bitSize = bitsize;
+		}
+
+		/// <summary>
+		/// NetDESEncryption constructor
+		/// </summary>
+		public NetDESEncryption(string key)
+			: this(key, m_keysizes[0])
+		{
+		}
+
+		/// <summary>
+		/// Encrypt outgoing message
+		/// </summary>
+		public bool Encrypt(NetOutgoingMessage msg)
+		{
+			try
+			{
+				// nested usings are fun!
+				using (DESCryptoServiceProvider desCryptoServiceProvider = new DESCryptoServiceProvider { KeySize = m_bitSize, Mode = CipherMode.CBC })
+				{
+					using (ICryptoTransform cryptoTransform = desCryptoServiceProvider.CreateEncryptor(m_key, m_iv))
+					{
+						using (MemoryStream memoryStream = new MemoryStream())
+						{
+							using (CryptoStream cryptoStream = new CryptoStream(memoryStream, cryptoTransform,
+																			 CryptoStreamMode.Write))
+							{
+								cryptoStream.Write(msg.m_data, 0, msg.m_data.Length);
+							}
+							msg.m_data = memoryStream.ToArray();
+						}
+					}
+				}
+
+			}
+			catch
+			{
+				return false;
+			}
+			return true;
+		}
+
+		/// <summary>
+		/// Decrypt incoming message
+		/// </summary>
+		public bool Decrypt(NetIncomingMessage msg)
+		{
+			try
+			{
+				// nested usings are fun!
+				using (DESCryptoServiceProvider desCryptoServiceProvider = new DESCryptoServiceProvider { KeySize = m_bitSize, Mode = CipherMode.CBC })
+				{
+					using (ICryptoTransform cryptoTransform = desCryptoServiceProvider.CreateDecryptor(m_key, m_iv))
+					{
+						using (MemoryStream memoryStream = new MemoryStream())
+						{
+							using (CryptoStream cryptoStream = new CryptoStream(memoryStream, cryptoTransform,
+																			 CryptoStreamMode.Write))
+							{
+								cryptoStream.Write(msg.m_data, 0, msg.m_data.Length);
+							}
+							msg.m_data = memoryStream.ToArray();
+						}
+					}
+				}
+
+			}
+			catch
+			{
+				return false;
+			}
+			return true;
+		}
+	}
+}

Lidgren.Network/Encryption/NetRC2Encryption.cs

@@ -0,0 +1,165 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Security.Cryptography;
+using System.Text;
+
+namespace Lidgren.Network
+{
+	/// <summary>
+	/// RC2 encryption
+	/// </summary>
+	public class NetRC2Encryption : INetEncryption
+	{
+		private readonly byte[] m_key;
+		private readonly byte[] m_iv;
+		private readonly int m_bitSize;
+		private static readonly List<int> m_keysizes;
+		private static readonly List<int> m_blocksizes;
+
+		static NetRC2Encryption()
+		{
+
+			RC2CryptoServiceProvider rc2 = new RC2CryptoServiceProvider();
+			List<int> temp = new List<int>();
+			foreach (KeySizes keysize in rc2.LegalKeySizes)
+			{
+				for (int i = keysize.MinSize; i <= keysize.MaxSize; i += keysize.SkipSize)
+				{
+					if (!temp.Contains(i))
+						temp.Add(i);
+					if (i == keysize.MaxSize)
+						break;
+				}
+			}
+			m_keysizes = temp;
+			temp = new List<int>();
+			foreach (KeySizes keysize in rc2.LegalBlockSizes)
+			{
+				for (int i = keysize.MinSize; i <= keysize.MaxSize; i += keysize.SkipSize)
+				{
+
+					if (!temp.Contains(i))
+						temp.Add(i);
+					if (i == keysize.MaxSize)
+						break;
+				}
+			}
+			m_blocksizes = temp;
+		}
+
+		/// <summary>
+		/// NetRC2Encryption constructor
+		/// </summary>
+		public NetRC2Encryption(byte[] key, byte[] iv)
+		{
+			if (!m_keysizes.Contains(key.Length * 8))
+				throw new NetException(string.Format("Not a valid key size. (Valid values are: {0})", NetUtility.MakeCommaDelimitedList(m_keysizes)));
+
+			if (!m_blocksizes.Contains(iv.Length * 8))
+				throw new NetException(string.Format("Not a valid iv size. (Valid values are: {0})", NetUtility.MakeCommaDelimitedList(m_blocksizes)));
+
+			m_key = key;
+			m_iv = iv;
+			m_bitSize = m_key.Length * 8;
+		}
+
+		/// <summary>
+		/// NetRC2Encryption constructor
+		/// </summary>
+		public NetRC2Encryption(string key, int bitsize)
+		{
+			if (!m_keysizes.Contains(bitsize))
+				throw new NetException(string.Format("Not a valid key size. (Valid values are: {0})", NetUtility.MakeCommaDelimitedList(m_keysizes)));
+				
+			byte[] entropy = Encoding.UTF32.GetBytes(key);
+			// I know hardcoding salts is bad, but in this case I think it is acceptable.
+			HMACSHA512 hmacsha512 = new HMACSHA512(Convert.FromBase64String("i88NEiez3c50bHqr3YGasDc4p8jRrxJAaiRiqixpvp4XNAStP5YNoC2fXnWkURtkha6M8yY901Gj07IRVIRyGL=="));
+			hmacsha512.Initialize();
+			for (int i = 0; i < 1000; i++)
+			{
+				entropy = hmacsha512.ComputeHash(entropy);
+			}
+			int keylen = bitsize / 8;
+			m_key = new byte[keylen];
+			Buffer.BlockCopy(entropy, 0, m_key, 0, keylen);
+			m_iv = new byte[m_blocksizes[0] / 8];
+
+			Buffer.BlockCopy(entropy, entropy.Length - m_iv.Length - 1, m_iv, 0, m_iv.Length);
+			m_bitSize = bitsize;
+		}
+
+		/// <summary>
+		/// NetRC2Encryption constructor
+		/// </summary>
+		/// <param name="key"></param>
+		public NetRC2Encryption(string key)
+			: this(key, m_keysizes[0])
+		{
+		}
+
+		/// <summary>
+		/// Encrypt outgoing message
+		/// </summary>
+		public bool Encrypt(NetOutgoingMessage msg)
+		{
+			try
+			{
+				// nested usings are fun!
+				using (RC2CryptoServiceProvider rc2CryptoServiceProvider = new RC2CryptoServiceProvider { KeySize = m_bitSize, Mode = CipherMode.CBC })
+				{
+					using (ICryptoTransform cryptoTransform = rc2CryptoServiceProvider.CreateEncryptor(m_key, m_iv))
+					{
+						using (MemoryStream memoryStream = new MemoryStream())
+						{
+							using (CryptoStream cryptoStream = new CryptoStream(memoryStream, cryptoTransform,
+																			 CryptoStreamMode.Write))
+							{
+								cryptoStream.Write(msg.m_data, 0, msg.m_data.Length);
+							}
+							msg.m_data = memoryStream.ToArray();
+						}
+					}
+				}
+
+			}
+			catch
+			{
+				return false;
+			}
+			return true;
+		}
+
+		/// <summary>
+		/// Decrypt incoming message
+		/// </summary>
+		public bool Decrypt(NetIncomingMessage msg)
+		{
+			try
+			{
+				// nested usings are fun!
+				using (RC2CryptoServiceProvider rc2CryptoServiceProvider = new RC2CryptoServiceProvider { KeySize = m_bitSize, Mode = CipherMode.CBC })
+				{
+					using (ICryptoTransform cryptoTransform = rc2CryptoServiceProvider.CreateDecryptor(m_key, m_iv))
+					{
+						using (MemoryStream memoryStream = new MemoryStream())
+						{
+							using (CryptoStream cryptoStream = new CryptoStream(memoryStream, cryptoTransform,
+																			 CryptoStreamMode.Write))
+							{
+								cryptoStream.Write(msg.m_data, 0, msg.m_data.Length);
+							}
+							msg.m_data = memoryStream.ToArray();
+						}
+					}
+				}
+
+			}
+			catch
+			{
+				return false;
+			}
+			return true;
+		}
+	}
+}

Lidgren.Network/Encryption/NetTripleDESEncryption.cs

@@ -0,0 +1,164 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Security.Cryptography;
+using System.Text;
+
+namespace Lidgren.Network
+{
+	/// <summary>
+	/// Triple DES encryption
+	/// </summary>
+	public class NetTripleDESEncryption : INetEncryption
+	{
+		private readonly byte[] m_key;
+		private readonly byte[] m_iv;
+		private readonly int m_bitSize;
+		private static readonly List<int> m_keysizes;
+		private static readonly List<int> m_blocksizes;
+
+		static NetTripleDESEncryption()
+		{
+
+			TripleDESCryptoServiceProvider tripleDES = new TripleDESCryptoServiceProvider();
+			List<int> temp = new List<int>();
+			foreach (KeySizes keysize in tripleDES.LegalKeySizes)
+			{
+				for (int i = keysize.MinSize; i <= keysize.MaxSize; i += keysize.SkipSize)
+				{
+					if (!temp.Contains(i))
+						temp.Add(i);
+					if (i == keysize.MaxSize)
+						break;
+				}
+			}
+			m_keysizes = temp;
+			temp = new List<int>();
+			foreach (KeySizes keysize in tripleDES.LegalBlockSizes)
+			{
+				for (int i = keysize.MinSize; i <= keysize.MaxSize; i += keysize.SkipSize)
+				{
+
+					if (!temp.Contains(i))
+						temp.Add(i);
+					if (i == keysize.MaxSize)
+						break;
+				}
+			}
+			m_blocksizes = temp;
+		}
+
+		/// <summary>
+		/// NetTriplsDESEncryption constructor
+		/// </summary>
+		public NetTripleDESEncryption(byte[] key, byte[] iv)
+		{
+			if (!m_keysizes.Contains(key.Length * 8))
+				throw new NetException(string.Format("Not a valid key size. (Valid values are: {0})", NetUtility.MakeCommaDelimitedList(m_keysizes)));
+
+			if (!m_blocksizes.Contains(iv.Length * 8))
+				throw new NetException(string.Format("Not a valid iv size. (Valid values are: {0})", NetUtility.MakeCommaDelimitedList(m_blocksizes)));
+
+			m_key = key;
+			m_iv = iv;
+			m_bitSize = m_key.Length * 8;
+		}
+
+		/// <summary>
+		/// NetTriplsDESEncryption constructor
+		/// </summary>
+		public NetTripleDESEncryption(string key, int bitsize)
+		{
+			if (!m_keysizes.Contains(bitsize))
+				throw new NetException(string.Format("Not a valid key size. (Valid values are: {0})", NetUtility.MakeCommaDelimitedList(m_keysizes)));
+
+			byte[] entropy = Encoding.UTF32.GetBytes(key);
+			// I know hardcoding salts is bad, but in this case I think it is acceptable.
+			HMACSHA512 hmacsha512 = new HMACSHA512(Convert.FromBase64String("i88NEiez3c50bHqr3YGasDc4p8jRrxJAaiRiqixpvp4XNAStP5YNoC2fXnWkURtkha6M8yY901Gj07IRVIRyGL=="));
+			hmacsha512.Initialize();
+			for (int i = 0; i < 1000; i++)
+			{
+				entropy = hmacsha512.ComputeHash(entropy);
+			}
+			int keylen = bitsize / 8;
+			m_key = new byte[keylen];
+			Buffer.BlockCopy(entropy, 0, m_key, 0, keylen);
+			m_iv = new byte[m_blocksizes[0] / 8];
+
+			Buffer.BlockCopy(entropy, entropy.Length - m_iv.Length - 1, m_iv, 0, m_iv.Length);
+			m_bitSize = bitsize;
+		}
+
+		/// <summary>
+		/// NetTriplsDESEncryption constructor
+		/// </summary>
+		public NetTripleDESEncryption(string key)
+			: this(key, m_keysizes[0])
+		{
+		}
+
+		/// <summary>
+		/// Encrypt outgoing message
+		/// </summary>
+		public bool Encrypt(NetOutgoingMessage msg)
+		{
+			try
+			{
+				// nested usings are fun!
+				using (TripleDESCryptoServiceProvider tripleDESCryptoServiceProvider = new TripleDESCryptoServiceProvider { KeySize = m_bitSize, Mode = CipherMode.CBC })
+				{
+					using (ICryptoTransform cryptoTransform = tripleDESCryptoServiceProvider.CreateEncryptor(m_key, m_iv))
+					{
+						using (MemoryStream memoryStream = new MemoryStream())
+						{
+							using (CryptoStream cryptoStream = new CryptoStream(memoryStream, cryptoTransform,
+																			 CryptoStreamMode.Write))
+							{
+								cryptoStream.Write(msg.m_data, 0, msg.m_data.Length);
+							}
+							msg.m_data = memoryStream.ToArray();
+						}
+					}
+				}
+
+			}
+			catch
+			{
+				return false;
+			}
+			return true;
+		}
+
+		/// <summary>
+		/// Decrypt incoming message
+		/// </summary>
+		public bool Decrypt(NetIncomingMessage msg)
+		{
+			try
+			{
+				// nested usings are fun!
+				using (TripleDESCryptoServiceProvider tripleDESCryptoServiceProvider = new TripleDESCryptoServiceProvider { KeySize = m_bitSize, Mode = CipherMode.CBC })
+				{
+					using (ICryptoTransform cryptoTransform = tripleDESCryptoServiceProvider.CreateDecryptor(m_key, m_iv))
+					{
+						using (MemoryStream memoryStream = new MemoryStream())
+						{
+							using (CryptoStream cryptoStream = new CryptoStream(memoryStream, cryptoTransform,
+																			 CryptoStreamMode.Write))
+							{
+								cryptoStream.Write(msg.m_data, 0, msg.m_data.Length);
+							}
+							msg.m_data = memoryStream.ToArray();
+						}
+					}
+				}
+
+			}
+			catch
+			{
+				return false;
+			}
+			return true;
+		}
+	}
+}

Lidgren.Network/Encryption/NetXorEncryption.cs

@@ -0,0 +1,58 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Lidgren.Network
+{
+	/// <summary>
+	/// Example class; not very good encryption
+	/// </summary>
+	public class NetXorEncryption : INetEncryption
+	{
+		private byte[] m_key;
+
+		/// <summary>
+		/// NetXorEncryption constructor
+		/// </summary>
+		public NetXorEncryption(byte[] key)
+		{
+			m_key = key;
+		}
+
+		/// <summary>
+		/// NetXorEncryption constructor
+		/// </summary>
+		public NetXorEncryption(string key)
+		{
+			m_key = Encoding.UTF8.GetBytes(key);
+		}
+
+		/// <summary>
+		/// Encrypt an outgoing message
+		/// </summary>
+		public bool Encrypt(NetOutgoingMessage msg)
+		{
+			int numBytes = msg.LengthBytes;
+			for (int i = 0; i < numBytes; i++)
+			{
+				int offset = i % m_key.Length;
+				msg.m_data[i] = (byte)(msg.m_data[i] ^ m_key[offset]);
+			}
+			return true;
+		}
+
+		/// <summary>
+		/// Decrypt an incoming message
+		/// </summary>
+		public bool Decrypt(NetIncomingMessage msg)
+		{
+			int numBytes = msg.LengthBytes;
+			for (int i = 0; i < numBytes; i++)
+			{
+				int offset = i % m_key.Length;
+				msg.m_data[i] = (byte)(msg.m_data[i] ^ m_key[offset]);
+			}
+			return true;
+		}
+	}
+}

Lidgren.Network/Encryption/NetXteaEncryption.cs

@@ -0,0 +1,146 @@
+/* Copyright (c) 2010 Michael Lidgren
+
+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 System.Text;
+using System.Security;
+
+namespace Lidgren.Network
+{
+	/// <summary>
+	/// Methods to encrypt and decrypt data using the XTEA algorithm
+	/// </summary>
+	public sealed class NetXtea : NetBlockEncryptionBase
+	{
+		private const int c_blockSize = 8;
+		private const int c_keySize = 16;
+		private const int c_delta = unchecked((int)0x9E3779B9);
+
+		private readonly int m_numRounds;
+		private readonly uint[] m_sum0;
+		private readonly uint[] m_sum1;
+
+		/// <summary>
+		/// Gets the block size for this cipher
+		/// </summary>
+		public override int BlockSize { get { return c_blockSize; } }
+
+		/// <summary>
+		/// 16 byte key
+		/// </summary>
+		public NetXtea(byte[] key, int rounds)
+		{
+			if (key.Length < c_keySize)
+				throw new NetException("Key too short!");
+
+			m_numRounds = rounds;
+			m_sum0 = new uint[m_numRounds];
+			m_sum1 = new uint[m_numRounds];
+			uint[] tmp = new uint[8];
+
+			int num2;
+			int index = num2 = 0;
+			while (index < 4)
+			{
+				tmp[index] = BitConverter.ToUInt32(key, num2);
+				index++;
+				num2 += 4;
+			}
+			for (index = num2 = 0; index < 32; index++)
+			{
+				m_sum0[index] = ((uint)num2) + tmp[num2 & 3];
+				num2 += -1640531527;
+				m_sum1[index] = ((uint)num2) + tmp[(num2 >> 11) & 3];
+			}
+		}
+
+		/// <summary>
+		/// 16 byte key
+		/// </summary>
+		public NetXtea(byte[] key)
+			: this(key, 32)
+		{
+		}
+
+		/// <summary>
+		/// String to hash for key
+		/// </summary>
+		public NetXtea(string key)
+			: this(SHA1.Create().ComputeHash(Encoding.UTF8.GetBytes(key)), 32)
+		{
+		}
+
+		/// <summary>
+		/// Encrypts a block of bytes
+		/// </summary>
+		protected override void EncryptBlock(byte[] source, int sourceOffset, byte[] destination)
+		{
+			uint v0 = BytesToUInt(source, sourceOffset);
+			uint v1 = BytesToUInt(source, sourceOffset + 4);
+
+			for (int i = 0; i != m_numRounds; i++)
+			{
+				v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ m_sum0[i];
+				v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ m_sum1[i];
+			}
+
+			UIntToBytes(v0, destination, 0);
+			UIntToBytes(v1, destination, 0 + 4);
+
+			return;
+		}
+
+		/// <summary>
+		/// Decrypts a block of bytes
+		/// </summary>
+		protected override void DecryptBlock(byte[] source, int sourceOffset, byte[] destination)
+		{
+			// Pack bytes into integers
+			uint v0 = BytesToUInt(source, sourceOffset);
+			uint v1 = BytesToUInt(source, sourceOffset + 4);
+
+			for (int i = m_numRounds - 1; i >= 0; i--)
+			{
+				v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ m_sum1[i];
+				v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ m_sum0[i];
+			}
+
+			UIntToBytes(v0, destination, 0);
+			UIntToBytes(v1, destination, 0 + 4);
+
+			return;
+		}
+
+		private static uint BytesToUInt(byte[] bytes, int offset)
+		{
+			uint retval = (uint)(bytes[offset] << 24);
+			retval |= (uint)(bytes[++offset] << 16);
+			retval |= (uint)(bytes[++offset] << 8);
+			return (retval | bytes[++offset]);
+		}
+
+		private static void UIntToBytes(uint value, byte[] destination, int destinationOffset)
+		{
+			destination[destinationOffset++] = (byte)(value >> 24);
+			destination[destinationOffset++] = (byte)(value >> 16);
+			destination[destinationOffset++] = (byte)(value >> 8);
+			destination[destinationOffset++] = (byte)value;
+		}
+	}
+}