password.cpp

VC6.0环境下开发

#include "stdafx.h"
#include "Password.h"
#include "string.h"
#include "MyPassword.h"

CPassWord::CPassWord()
{
	m_change = 4823013431;
}

CPassWord::ecfile(LPCTSTR fpath)
{
	CFile *file;
	file = new CFile;
	//打开文件
	if (!file->Open(fpath,CFile::shareDenyNone|CFile::modeReadWrite))
	{
		MessageBox(NULL,"No such file or can not open it","Mistakes",MB_OK);
		
		delete file;
		file = NULL;

		return FALSE;
	}
	
	/////判断该文件是否已经被加密(加密后文件尾为***)
	char *IsAdded = new char[4];
	file->Seek(-4,CFile::end);
	file->Read(IsAdded,4);
    if (!strcmp(IsAdded,"***"))
	{ 
		MessageBox(NULL,"文件已加密,无法再次加密","加密",MB_OK);
		file->Close();
		
		delete []IsAdded;
		IsAdded = NULL;
		delete file;
		file = NULL;
		
		return FALSE;
	}

	file->SeekToBegin();
	//
	int flen = file->GetLength();
	char * data = new char[flen];
	//将文件信息读入data中
	file->Read(data,flen);
	//将data中的数据进行异或操作(加密)
	for (int i=0;i<flen;i++)
	{
		data[i] ^= m_change;
	}
    
	file->SeekToBegin();
	//将加密后的数据写入文件中
	file->Write(data,flen);
	file->SeekToEnd();
	
	//将密码异或后写如文件中
	char *str = new char[g_string.GetLength()+1];
	for (i=0;i<g_string.GetLength();i++) 
	{
		str[i] = g_string.GetAt(i);
		str[i] ^= m_change;
	}
	str[i] = '\0';
	g_string.Format(str);
	
	file->Write(g_string,g_string.GetLength());
	//将***写入文件中，用作判断文件是否已经被加密的标志
	file->Write("***",4);
	//
	file->Close();
	//释放堆空间
	delete file;
	file = NULL;
	delete []data;
	data = NULL;
	delete []str;
	str = NULL;
	MessageBox(NULL,"文件已经加密","加密",MB_OK);
	return TRUE;
}


CPassWord::dcfile(LPCTSTR fpath)
{
	CFile *file;
	file = new CFile;
	//打开要解密的文件
	if (!file->Open(fpath,CFile::shareDenyNone|CFile::modeReadWrite))
	{
		
		MessageBox(NULL,"No such file or can not open it","Mistakes",MB_OK);
        return FALSE;
	}
    //检验文件是否已经加密
	char *IsAdded = new char[4];
	file->Seek(-4,CFile::end);

	//将文件尾的信息读入IsAdded中
	file->Read(IsAdded,4);
	
	//判断文件是否被加密过
	if (strcmp(IsAdded,"***"))
	{
		MessageBox(NULL,"文件尚未加密","加密",MB_OK);
		file->Close();
		delete []IsAdded;
		IsAdded = NULL;
		delete file;
		file = NULL;
		return FALSE;
	}

	file->SeekToBegin();
	
	int flen = file->GetLength();
	
	char *data = new char[flen];//文件数据信息
	
	char *check =new char[g_string.GetLength()+1];//密码判断
	


	file->Seek(-g_string.GetLength()-4,CFile::end);
	file->Read(check,g_string.GetLength());
	check[g_string.GetLength()] = '\0';
	for (int i=0;i<g_string.GetLength();i++)
	{
		check[i] ^= m_change; 
	}
	
	//判断密码是否正确
	if (strcmp(g_string,check))
	{
		delete []check;
		check =NULL;
		delete []data;
		data = NULL;
		MessageBox(NULL,"密码错误，无法解密","解密失败",MB_OK);
		return FALSE;
	}
    
	file->SeekToBegin();
	//读入文件数据
	file->Read(data,flen-g_string.GetLength()-4);
	
	//将文件数据进行异或(解密)
	for( i=0;i<flen-g_string.GetLength();i++)
	{
		data[i] ^= m_change; 
	}
	
	//将解密后的数据写入文件中
	file->SeekToBegin();
	file->Write(data,flen-g_string.GetLength()-4);
	file->SetLength(flen-g_string.GetLength()-4);
	file->Close();
	
	delete file;
	file = NULL;
    
	MessageBox(NULL,"文件已经成功解密","解密",MB_OK);
	return TRUE;
}