Setup solution

ModernKeePassLib/Cryptography/Cipher/StandardAesEngine.cs

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+/*
+  KeePass Password Safe - The Open-Source Password Manager
+  Copyright (C) 2003-2019 Dominik Reichl <dominik.reichl@t-online.de>
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  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
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.IO;
+using System.Security;
+using System.Text;
+
+#if !KeePassUAP
+using System.Security.Cryptography;
+#endif
+
+using ModernKeePassLib.Resources;
+
+namespace ModernKeePassLib.Cryptography.Cipher
+{
+	public sealed class StandardAesEngine : ICipherEngine
+	{
+#if !KeePassUAP
+		private const CipherMode SaeCipherMode = CipherMode.CBC;
+		private const PaddingMode SaePaddingMode = PaddingMode.PKCS7;
+#endif
+
+		private static PwUuid g_uuidAes = null;
+		public static PwUuid AesUuid
+		{
+			get
+			{
+				PwUuid pu = g_uuidAes;
+				if(pu == null)
+				{
+					pu = new PwUuid(new byte[] {
+						0x31, 0xC1, 0xF2, 0xE6, 0xBF, 0x71, 0x43, 0x50,
+						0xBE, 0x58, 0x05, 0x21, 0x6A, 0xFC, 0x5A, 0xFF });
+					g_uuidAes = pu;
+				}
+
+				return pu;
+			}
+		}
+
+		public PwUuid CipherUuid
+		{
+			get { return StandardAesEngine.AesUuid; }
+		}
+
+		public string DisplayName
+		{
+			get
+			{
+				return ("AES/Rijndael (" + KLRes.KeyBits.Replace(@"{PARAM}",
+					"256") + ", FIPS 197)");
+			}
+		}
+
+		private static void ValidateArguments(Stream s, bool bEncrypt, byte[] pbKey, byte[] pbIV)
+		{
+			if(s == null) { Debug.Assert(false); throw new ArgumentNullException("s"); }
+
+			if(pbKey == null) { Debug.Assert(false); throw new ArgumentNullException("pbKey"); }
+			if(pbKey.Length != 32) { Debug.Assert(false); throw new ArgumentOutOfRangeException("pbKey"); }
+
+			if(pbIV == null) { Debug.Assert(false); throw new ArgumentNullException("pbIV"); }
+			if(pbIV.Length != 16) { Debug.Assert(false); throw new ArgumentOutOfRangeException("pbIV"); }
+
+			if(bEncrypt)
+			{
+				Debug.Assert(s.CanWrite);
+				if(!s.CanWrite) throw new ArgumentException("Stream must be writable!");
+			}
+			else // Decrypt
+			{
+				Debug.Assert(s.CanRead);
+				if(!s.CanRead) throw new ArgumentException("Stream must be readable!");
+			}
+		}
+
+		private static Stream CreateStream(Stream s, bool bEncrypt, byte[] pbKey, byte[] pbIV)
+		{
+			StandardAesEngine.ValidateArguments(s, bEncrypt, pbKey, pbIV);
+
+#if KeePassUAP
+			return StandardAesEngineExt.CreateStream(s, bEncrypt, pbKey, pbIV);
+#else
+			SymmetricAlgorithm a = CryptoUtil.CreateAes();
+			if(a.BlockSize != 128) // AES block size
+			{
+				Debug.Assert(false);
+				a.BlockSize = 128;
+			}
+			a.KeySize = 256;
+			a.Mode = SaeCipherMode;
+			a.Padding = SaePaddingMode;
+
+			ICryptoTransform t;
+			if(bEncrypt) t = a.CreateEncryptor(pbKey, pbIV);
+			else t = a.CreateDecryptor(pbKey, pbIV);
+			if(t == null) { Debug.Assert(false); throw new SecurityException("Unable to create AES transform!"); }
+
+			return new CryptoStreamEx(s, t, bEncrypt ? CryptoStreamMode.Write :
+				CryptoStreamMode.Read, a);
+#endif
+		}
+
+		public Stream EncryptStream(Stream s, byte[] pbKey, byte[] pbIV)
+		{
+			return StandardAesEngine.CreateStream(s, true, pbKey, pbIV);
+		}
+
+		public Stream DecryptStream(Stream s, byte[] pbKey, byte[] pbIV)
+		{
+			return StandardAesEngine.CreateStream(s, false, pbKey, pbIV);
+		}
+	}
+}