GARbro-mirror/ArcFormats/Malie/MalieEncryption.cs

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//! \file MalieEncryption.cs
//! \date Tue Jun 06 20:38:57 2017
//! \brief Malie System encryption implementation.
//
// Copyright (C) 2017 by morkt
//
// 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.IO;
using GameRes.Cryptography;
using GameRes.Utility;
namespace GameRes.Formats.Malie
{
public interface IMalieDecryptor
{
void DecryptBlock (long block_offset, byte[] buffer, int index);
}
public class CamelliaDecryptor : IMalieDecryptor
{
Camellia m_enc;
public CamelliaDecryptor (uint[] key)
{
m_enc = new Camellia (key);
}
public void DecryptBlock (long block_offset, byte[] buffer, int index)
{
m_enc.DecryptBlock (block_offset, buffer, index);
}
}
public class CfiDecryptor : IMalieDecryptor
{
byte[] m_key;
public CfiDecryptor (byte[] key)
{
m_key = key;
}
public void DecryptBlock (long block_offset, byte[] data, int index)
{
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if (null == data)
throw new ArgumentNullException ("data");
if (index < 0 || index + 0x10 > data.Length)
throw new ArgumentOutOfRangeException ("index");
int offset = (int)block_offset;
int o = offset & 0xF;
byte first = data[index+o];
for (int i = 0; i < 0x10; ++i)
{
if (o != i)
data[index+i] ^= first;
}
offset >>= 4;
unsafe
{
fixed (byte* data8 = &data[index])
{
uint* data32 = (uint*)data8;
uint k = Binary.RotR (0x39653542, m_key[offset & 0x1F] ^ 0xA5);
data32[0] = Binary.RotR (data32[0] ^ k, m_key[(offset + 12) & 0x1F] ^ 0xA5);
k = Binary.RotL (0x76706367, m_key[(offset + 3) & 0x1F] ^ 0xA5);
data32[1] = Binary.RotL (data32[1] ^ k, m_key[(offset + 15) & 0x1F] ^ 0xA5);
k = Binary.RotR (0x69454462, m_key[(offset + 6) & 0x1F] ^ 0xA5);
data32[2] = Binary.RotR (data32[2] ^ k, m_key[(offset - 14) & 0x1F] ^ 0xA5);
k = Binary.RotL (0x71334334, m_key[(offset + 9) & 0x1F] ^ 0xA5);
data32[3] = Binary.RotL (data32[3] ^ k, m_key[(offset - 11) & 0x1F] ^ 0xA5);
}
}
}
}
internal class EncryptedStream : Stream
{
ArcView.Frame m_view;
IMalieDecryptor m_dec;
long m_max_offset;
long m_position = 0;
byte[] m_current_block = new byte[BlockLength];
int m_current_block_length = 0;
long m_current_block_position = 0;
public const int BlockLength = 0x1000;
public IMalieDecryptor Decryptor { get { return m_dec; } }
public EncryptedStream (ArcView mmap, IMalieDecryptor decryptor)
{
m_view = mmap.CreateFrame();
m_dec = decryptor;
m_max_offset = mmap.MaxOffset;
}
public override int Read (byte[] buf, int index, int count)
{
int total_read = 0;
bool refill_buffer = !(m_position >= m_current_block_position && m_position < m_current_block_position + m_current_block_length);
while (count > 0 && m_position < m_max_offset)
{
if (refill_buffer)
{
m_current_block_position = m_position & ~((long)BlockLength-1);
FillBuffer();
}
int src_offset = (int)m_position & (BlockLength-1);
int available = Math.Min (count, m_current_block_length - src_offset);
Buffer.BlockCopy (m_current_block, src_offset, buf, index, available);
m_position += available;
total_read += available;
index += available;
count -= available;
refill_buffer = true;
}
return total_read;
}
private void FillBuffer ()
{
m_current_block_length = m_view.Read (m_current_block_position, m_current_block, 0, (uint)BlockLength);
for (int offset = 0; offset < m_current_block_length; offset += 0x10)
{
m_dec.DecryptBlock (m_current_block_position+offset, m_current_block, offset);
}
}
#region IO.Stream methods
public override bool CanRead { get { return !m_disposed; } }
public override bool CanWrite { get { return false; } }
public override bool CanSeek { get { return !m_disposed; } }
public override long Length { get { return m_max_offset; } }
public override long Position
{
get { return m_position; }
set { m_position = value; }
}
public override long Seek (long pos, SeekOrigin whence)
{
if (SeekOrigin.Current == whence)
m_position += pos;
else if (SeekOrigin.End == whence)
m_position = m_max_offset + pos;
else
m_position = pos;
return m_position;
}
public override void Write (byte[] buf, int index, int count)
{
throw new NotSupportedException();
}
public override void SetLength (long length)
{
throw new NotSupportedException();
}
public override void Flush ()
{
}
#endregion
#region IDisposable methods
bool m_disposed = false;
protected override void Dispose (bool disposing)
{
if (!m_disposed)
{
if (disposing)
m_view.Dispose();
m_disposed = true;
base.Dispose();
}
}
#endregion
}
}