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////////////////////////////////////////////////////////////////////////////////
// This source file is part of the ZipArchive library source distribution and
// is Copyrighted 2000 - 2007 by Artpol Software - Tadeusz Dracz
//
// 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.
//
// For the licensing details refer to the License.txt file.
//
// Web Site: http://www.artpol-software.com
////////////////////////////////////////////////////////////////////////////////
/**
* \file ZipCrc32Cryptograph.h
* Includes the CZipCrc32Cryptograph class.
*
*/
#if !defined(ZIPARCHIVE_ZIPCRC32CRYPTOGRAPH_DOT_H)
#define ZIPARCHIVE_ZIPCRC32CRYPTOGRAPH_DOT_H
#if _MSC_VER > 1000
#pragma once
#endif
#include "zlib/zlib.h"
#include "ZipCryptograph.h"
#include "ZipFileHeader.h"
#include "ZipStorage.h"
#define ZIPARCHIVE_ENCR_HEADER_LEN 12
/**
Performs the traditional zip encryption.
\see
<a href="kb">0610201627|std</a>
*/
class ZIP_API CZipCrc32Cryptograph : public CZipCryptograph
{
public:
CZipCrc32Cryptograph(){}
bool InitDecode(CZipAutoBuffer& password, CZipFileHeader& currentFile, CZipStorage& storage);
void InitEncode(CZipAutoBuffer& password, CZipFileHeader& currentFile, CZipStorage& storage);
void Decode(char* pBuffer, DWORD uSize)
{
for (DWORD i = 0; i < uSize; i++)
CryptDecode(pBuffer[i]);
}
void Encode(char* pBuffer, DWORD uSize)
{
for (DWORD i = 0; i < uSize; i++)
CryptEncode(pBuffer[i]);
}
bool CanHandle(int iEncryptionMethod)
{
return iEncryptionMethod == CZipCryptograph::encStandard;
}
/**
See CZipCryptograph::GetEncryptedInfoSizeBeforeData
*/
static DWORD GetEncryptedInfoSizeBeforeData()
{
return ZIPARCHIVE_ENCR_HEADER_LEN;
}
/**
See CZipCryptograph::GetEncryptedInfoSizeAfterData
*/
static DWORD GetEncryptedInfoSizeAfterData()
{
return 0;
}
/**
Returns the CRC table.
*/
static const DWORD* GetCRCTable()
{
return zarch_get_crc_table();
}
private:
void CryptDecode(char &c)
{
c ^= CryptDecryptByte();
CryptUpdateKeys(c);
}
char CryptDecryptByte()
{
int temp = (m_keys[2] & 0xffff) | 2;
return (char)(((temp * (temp ^ 1)) >> 8) & 0xff);
}
void CryptInitKeys(CZipAutoBuffer& password);
void CryptUpdateKeys(char c);
DWORD CryptCRC32(DWORD l, char c)
{
const DWORD *CRC_TABLE = zarch_get_crc_table();
return CRC_TABLE[(l ^ c) & 0xff] ^ (l >> 8);
}
void CryptEncode(char &c)
{
char t = CryptDecryptByte();
CryptUpdateKeys(c);
c ^= t;
}
DWORD m_keys[3];
public:
~CZipCrc32Cryptograph(){}
};
#endif
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