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#region Disclaimer / License
// Copyright (C) 2011, Kenneth Skovhede
// http://www.hexad.dk, opensource@hexad.dk
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
//
#endregion
using System;
using System.Collections.Generic;
using System.Text;
using Duplicati.Library.Interface;
namespace Duplicati.Library.Encryption
{
/// <summary>
/// Simple helper class that implements the filebased functions, and wraps them onto the stream based ones
/// </summary>
public abstract class EncryptionBase : IEncryption
{
private readonly byte[] m_copybuffer = new byte[Duplicati.Library.Utility.Utility.DEFAULT_BUFFER_SIZE];
#region IEncryption Members
public abstract IList<ICommandLineArgument> SupportedCommands { get; }
public abstract string FilenameExtension { get; }
public abstract string DisplayName { get; }
public abstract string Description { get; }
protected abstract void Dispose(bool disposing);
public virtual void Encrypt(string inputfile, string outputfile)
{
using (System.IO.FileStream fs1 = System.IO.File.OpenRead(inputfile))
using (System.IO.FileStream fs2 = System.IO.File.Create(outputfile))
this.Encrypt(fs1, fs2);
}
public virtual void Encrypt(System.IO.Stream input, System.IO.Stream output)
{
using (System.IO.Stream cs = Encrypt(output))
Utility.Utility.CopyStream(input, cs, true, m_copybuffer);
}
public abstract System.IO.Stream Encrypt(System.IO.Stream input);
public virtual void Decrypt(string inputfile, string outputfile)
{
using (System.IO.FileStream fs1 = System.IO.File.OpenRead(inputfile))
using (System.IO.FileStream fs2 = System.IO.File.Create(outputfile))
this.Decrypt(fs1, fs2);
}
public abstract System.IO.Stream Decrypt(System.IO.Stream input);
public virtual long SizeOverhead(long filesize)
{
using (Utility.TempFile t1 = new Duplicati.Library.Utility.TempFile())
using (Utility.TempFile t2 = new Duplicati.Library.Utility.TempFile())
{
using (System.IO.Stream s1 = System.IO.File.Create(t1))
{
long bytesleft = filesize;
byte[] buf = new byte[1024];
Random rnd = new Random();
while (bytesleft > 0)
{
rnd.NextBytes(buf);
s1.Write(buf, 0, (int)Math.Min(buf.Length, bytesleft));
bytesleft -= buf.Length;
}
}
Encrypt(t1, t2);
return Math.Max(0, new System.IO.FileInfo(t2).Length - filesize);
}
}
public virtual void Decrypt(System.IO.Stream input, System.IO.Stream output)
{
try
{
using (System.IO.Stream cs = Decrypt(input))
Utility.Utility.CopyStream(cs, output, true, m_copybuffer);
}
catch (System.Security.Cryptography.CryptographicException cex)
{
//Better error message than "Padding is invalid and cannot be removed" :)
throw new System.Security.Cryptography.CryptographicException(string.Format(Strings.EncryptionBase.DecryptionError, cex.Message), cex);
}
}
#endregion
#region IDisposable Members
public void Dispose()
{
Dispose(true);
}
#endregion
}
}
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