KeePassLib finally portable (but version 2.19)

Windows Store project stub

ModernKeePassLib/Security/XorredBuffer.cs

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+/*
+  KeePass Password Safe - The Open-Source Password Manager
+  Copyright (C) 2003-2012 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.Diagnostics;
+
+namespace ModernKeePassLib.Security
+{
+	/// <summary>
+	/// Represents an object that is encrypted using a XOR pad until
+	/// it is read. <c>XorredBuffer</c> objects are immutable and
+	/// thread-safe.
+	/// </summary>
+	public sealed class XorredBuffer
+	{
+		private byte[] m_pbData; // Never null
+		private byte[] m_pbXorPad; // Always valid for m_pbData
+
+		/// <summary>
+		/// Length of the protected data in bytes.
+		/// </summary>
+		public uint Length
+		{
+			get { return (uint)m_pbData.Length; }
+		}
+
+		/// <summary>
+		/// Construct a new XOR-protected object using a protected byte array
+		/// and a XOR pad that decrypts the protected data. The
+		/// <paramref name="pbProtectedData" /> byte array must have the same size
+		/// as the <paramref name="pbXorPad" /> byte array.
+		/// The <c>XorredBuffer</c> object takes ownership of the two byte
+		/// arrays, i.e. the caller must not use or modify them afterwards.
+		/// </summary>
+		/// <param name="pbProtectedData">Protected data (XOR pad applied).</param>
+		/// <param name="pbXorPad">XOR pad that can be used to decrypt the
+		/// <paramref name="pbProtectedData" /> parameter.</param>
+		/// <exception cref="System.ArgumentNullException">Thrown if one of the input
+		/// parameters is <c>null</c>.</exception>
+		/// <exception cref="System.ArgumentException">Thrown if the byte arrays are
+		/// of different size.</exception>
+		public XorredBuffer(byte[] pbProtectedData, byte[] pbXorPad)
+		{
+			if(pbProtectedData == null) { Debug.Assert(false); throw new ArgumentNullException("pbProtectedData"); }
+			if(pbXorPad == null) { Debug.Assert(false); throw new ArgumentNullException("pbXorPad"); }
+
+			Debug.Assert(pbProtectedData.Length == pbXorPad.Length);
+			if(pbProtectedData.Length != pbXorPad.Length) throw new ArgumentException();
+
+			m_pbData = pbProtectedData;
+			m_pbXorPad = pbXorPad;
+		}
+
+		/// <summary>
+		/// Get a copy of the plain-text. The caller is responsible
+		/// for clearing the byte array safely after using it.
+		/// </summary>
+		/// <returns>Unprotected plain-text byte array.</returns>
+		public byte[] ReadPlainText()
+		{
+			byte[] pbPlain = new byte[m_pbData.Length];
+
+			for(int i = 0; i < pbPlain.Length; ++i)
+				pbPlain[i] = (byte)(m_pbData[i] ^ m_pbXorPad[i]);
+
+			return pbPlain;
+		}
+
+		/* public bool EqualsValue(XorredBuffer xb)
+		{
+			if(xb == null) { Debug.Assert(false); throw new ArgumentNullException("xb"); }
+
+			if(xb.m_pbData.Length != m_pbData.Length) return false;
+
+			for(int i = 0; i < m_pbData.Length; ++i)
+			{
+				byte bt1 = (byte)(m_pbData[i] ^ m_pbXorPad[i]);
+				byte bt2 = (byte)(xb.m_pbData[i] ^ xb.m_pbXorPad[i]);
+
+				if(bt1 != bt2) return false;
+			}
+
+			return true;
+		}
+
+		public bool EqualsValue(byte[] pb)
+		{
+			if(pb == null) { Debug.Assert(false); throw new ArgumentNullException("pb"); }
+
+			if(pb.Length != m_pbData.Length) return false;
+
+			for(int i = 0; i < m_pbData.Length; ++i)
+			{
+				if((byte)(m_pbData[i] ^ m_pbXorPad[i]) != pb[i]) return false;
+			}
+
+			return true;
+		} */
+	}
+}