VC++信息安全编程（１０）基于一阶Bézier曲线的信息隐藏编程实例

信息隐藏指在设计和确定模块时，使得一个模块内包含的特定信息（过程或数据），对于不需要这些信息的其他模块来说，是透明的。

传统的信息隐藏起源于古老的隐写术。如在古希腊战争中，为了安全地传送军事情报，奴隶主剃光奴隶 的头发，将情报文在奴隶的头皮上，待头发长起后再派出去传送消息。我国古代也早有以藏头诗、藏尾诗、漏格诗以及绘画等形式，将要表达的意思和“密语”隐藏在诗文或画卷中的特定位置，一般人只注意诗或画的表面意境，而不会去注意或破解隐藏其中的密语。 　　信息隐藏的发展历史可以一直追溯到"匿形术（Steganography）"的使用。"匿形术"一词来源于古希腊文中"隐藏的"和"图形"两个词语的组合。虽然"匿形术"与"密码术（Cryptography）"都是致力于信息的保密技术，但是，两者的设计思想却完全不同。"密码术"主要通过设计加密技术，使保密信息不可读，但是对于非授权者来讲，虽然他无法获知保密信息的具体内容，却能意识到保密信息的存在。而"匿形术"则致力于通过设计精妙的方法，使得非授权者根本无从得知保密信息的存在与否。相对于现代密码学来讲，信息隐藏的最大优势在于它并不限制对主信号的存取和访问，而是致力于签字信号的安全保密性。

我们来实践一个基于一阶Bézier曲线的信息隐藏编程实例 ，需要一定的数学基础，请见代码分析。

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CAboutDlg dialog used for App About

class CAboutDlg : public CDialog
{
public:
	CAboutDlg();

// Dialog Data
	//{{AFX_DATA(CAboutDlg)
	enum { IDD = IDD_ABOUTBOX };
	//}}AFX_DATA

	// ClassWizard generated virtual function overrides
	//{{AFX_VIRTUAL(CAboutDlg)
	protected:
	virtual void DoDataExchange(CDataExchange* pDX);    // DDX/DDV support
	//}}AFX_VIRTUAL

// Implementation
protected:
	//{{AFX_MSG(CAboutDlg)
	//}}AFX_MSG
	DECLARE_MESSAGE_MAP()
};

CAboutDlg::CAboutDlg() : CDialog(CAboutDlg::IDD)
{
	//{{AFX_DATA_INIT(CAboutDlg)
	//}}AFX_DATA_INIT
}

void CAboutDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CAboutDlg)
	//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CAboutDlg, CDialog)
	//{{AFX_MSG_MAP(CAboutDlg)
		// No message handlers
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CDataHideInBMPBZDlg dialog

CDataHideInBMPBZDlg::CDataHideInBMPBZDlg(CWnd* pParent /*=NULL*/)
	: CDialog(CDataHideInBMPBZDlg::IDD, pParent)
{
	//{{AFX_DATA_INIT(CDataHideInBMPBZDlg)
		// NOTE: the ClassWizard will add member initialization here
	//}}AFX_DATA_INIT
	// Note that LoadIcon does not require a subsequent DestroyIcon in Win32

	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CDataHideInBMPBZDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CDataHideInBMPBZDlg)
		// NOTE: the ClassWizard will add DDX and DDV calls here
	//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CDataHideInBMPBZDlg, CDialog)
	//{{AFX_MSG_MAP(CDataHideInBMPBZDlg)
	ON_WM_SYSCOMMAND()
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	ON_BN_CLICKED(IDC_BASEBMP_HIDE, OnBasebmpHide)
	ON_BN_CLICKED(IDC_HIDEFILE, OnHidefile)
	ON_BN_CLICKED(IDC_DOHIDE, OnDohide)
	ON_BN_CLICKED(IDC_BASEBMP_RESUME, OnBasebmpResume)
	ON_BN_CLICKED(IDC_BASEFILE, OnBasefile)
	ON_BN_CLICKED(IDC_RESUMEDATA, OnResumedata)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CDataHideInBMPBZDlg message handlers

BOOL CDataHideInBMPBZDlg::OnInitDialog()
{
	CDialog::OnInitDialog();

	// Add "About..." menu item to system menu.

	// IDM_ABOUTBOX must be in the system command range.
	ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
	ASSERT(IDM_ABOUTBOX < 0xF000);

	CMenu* pSysMenu = GetSystemMenu(FALSE);
	if (pSysMenu != NULL)
	{
		CString strAboutMenu;
		strAboutMenu.LoadString(IDS_ABOUTBOX);
		if (!strAboutMenu.IsEmpty())
		{
			pSysMenu->AppendMenu(MF_SEPARATOR);
			pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
		}
	}

	// Set the icon for this dialog.  The framework does this automatically
	//  when the application's main window is not a dialog
	SetIcon(m_hIcon, TRUE);			// Set big icon
	SetIcon(m_hIcon, FALSE);		// Set small icon
	
	// TODO: Add extra initialization here
	t=0.035;		//融合系数
	m_bBaseBMPHide=false;
	m_bBaseBMPResume=false;
	m_bHidefile=false;
	m_bBasefile=false;
	GetDlgItem(IDC_DOHIDE)->EnableWindow(m_bBaseBMPHide && m_bHidefile);
	GetDlgItem(IDC_RESUMEDATA)->EnableWindow(m_bBaseBMPResume && m_bBasefile);

	return TRUE;  // return TRUE  unless you set the focus to a control
}

void CDataHideInBMPBZDlg::OnSysCommand(UINT nID, LPARAM lParam)
{
	if ((nID & 0xFFF0) == IDM_ABOUTBOX)
	{
		CAboutDlg dlgAbout;
		dlgAbout.DoModal();
	}
	else
	{
		CDialog::OnSysCommand(nID, lParam);
	}
}

// If you add a minimize button to your dialog, you will need the code below
//  to draw the icon.  For MFC applications using the document/view model,
//  this is automatically done for you by the framework.

void CDataHideInBMPBZDlg::OnPaint() 
{
	if (IsIconic())
	{
		CPaintDC dc(this); // device context for painting

		SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);

		// Center icon in client rectangle
		int cxIcon = GetSystemMetrics(SM_CXICON);
		int cyIcon = GetSystemMetrics(SM_CYICON);
		CRect rect;
		GetClientRect(&rect);
		int x = (rect.Width() - cxIcon + 1) / 2;
		int y = (rect.Height() - cyIcon + 1) / 2;

		// Draw the icon
		dc.DrawIcon(x, y, m_hIcon);
	}
	else
	{
		CDialog::OnPaint();
	}
}

// The system calls this to obtain the cursor to display while the user drags
//  the minimized window.
HCURSOR CDataHideInBMPBZDlg::OnQueryDragIcon()
{
	return (HCURSOR) m_hIcon;
}

unsigned char CDataHideInBMPBZDlg::HideCalculate(unsigned char B, unsigned char H)
{
	unsigned char R=(int)((1-t)*B+0.5f)+(int)(t*H+0.5f);
	return R;
}

unsigned char CDataHideInBMPBZDlg::ShowCalculate(unsigned char C, unsigned char B)
{
	unsigned char R=(int)((C- (int)((1-t)*B+0.5f))/t+0.5f);
	if(R%32>15)
		R+=15;
	R=(int)(R/32.0f+0.5f);
	return R;
}


void CDataHideInBMPBZDlg::OnBasebmpHide() 
{
	// TODO: Add your control notification handler code here
	CFileDialog dlg(TRUE,"bmp","*.bmp",OFN_HIDEREADONLY|OFN_OVERWRITEPROMPT,"载体位图文件(*.bmp)|*.bmp||",NULL);
	if(dlg.DoModal()==IDOK)
	{
		m_bBaseBMPHide=true;
		m_sCarrierFileHide=dlg.GetPathName();
		GetDlgItem(IDC_BASEBMP_HIDE)->SetWindowText(m_sCarrierFileHide);
	}
	else
		m_bBaseBMPHide=false;
	GetDlgItem(IDC_DOHIDE)->EnableWindow(m_bBaseBMPHide && m_bHidefile);
}

void CDataHideInBMPBZDlg::OnHidefile() 
{
	// TODO: Add your control notification handler code here
	CFileDialog dlg(TRUE,"*","*.*",OFN_HIDEREADONLY|OFN_OVERWRITEPROMPT,"待隐藏文件(*.*)|*.*||",NULL);
	if(dlg.DoModal()==IDOK)
	{
		m_bHidefile=true;
		m_sHideFile=dlg.GetPathName();
		m_sHideFileName=dlg.GetFileName();
		GetDlgItem(IDC_HIDEFILE)->SetWindowText(m_sHideFileName);
	}
	else
		m_bHidefile=false;
	GetDlgItem(IDC_DOHIDE)->EnableWindow(m_bBaseBMPHide && m_bHidefile);
}

void CDataHideInBMPBZDlg::OnDohide() 
{
	// TODO: Add your control notification handler code here
	CFile BaseFile,HideFile;
	DWORD BaseFileLen,HideFileLen;
	
	unsigned char* BaseData;
	unsigned char* HideData;

	
	if(m_bBaseBMPHide==true && m_bHidefile==true)
	{
		BaseFile.Open(m_sCarrierFileHide,CFile::modeReadWrite);
		BaseFileLen=BaseFile.GetLength();
		HideFile.Open(m_sHideFile,CFile::modeReadWrite);
		HideFileLen=HideFile.GetLength();
		
		//信息头：文件名*文件长*
		CString	InfoHead;
		InfoHead.Format("%s*%d*",m_sHideFileName,HideFileLen);
		int HeadLen=InfoHead.GetLength();
		
		if(BaseFileLen<((HeadLen+HideFileLen)*8)/3+100)
		{
			AfxMessageBox("待隐藏文件过大!请换一较大载体位图文件。");
			return;
		}

		BaseData=new unsigned char[BaseFileLen];
		BaseFile.Read(BaseData,BaseFileLen);
		HideData=new unsigned char[BaseFileLen];
		//对明文进行组帧
		for(int k=0;k<HeadLen;k++)
			HideData[k]=InfoHead.GetAt(k);
		HideFile.Read(HideData+HeadLen,HideFileLen);
		for(DWORD kk=HeadLen+HideFileLen;kk<BaseFileLen;kk++)
			HideData[kk]=0;

		if(BaseData[28]!=24)
		{
			AfxMessageBox("载体文件格式错误!");
			BaseFile.Close();
			if(BaseData!=NULL)
				delete BaseData;
			return;
		}
		unsigned char Temp=0;
		DWORD j=0;
		for(DWORD i=54;i<BaseFileLen;i++)
		{
			Temp=((HideData[j]&224)>>5)<<5;		//1
			BaseData[i]=HideCalculate(BaseData[i],Temp);
			i++;
			Temp=((HideData[j]&28)>>2)<<5;		//2
			BaseData[i]=HideCalculate(BaseData[i],Temp);
			i++;
			Temp=(HideData[j]&3)<<1;			//3
			j++;
			Temp|=(HideData[j]&128)>>7;
			Temp*=32;
			BaseData[i]=HideCalculate(BaseData[i],Temp);
			i++;
			Temp=((HideData[j]&112)>>4)<<5;		//4
			BaseData[i]=HideCalculate(BaseData[i],Temp);
			i++;
			Temp=((HideData[j]&14)>>1)<<5;		//5
			BaseData[i]=HideCalculate(BaseData[i],Temp);
			i++;
			Temp=(HideData[j]&1)<<2;			//6
			j++;
			Temp|=(HideData[j]&192)>>6;
			Temp*=32;
			BaseData[i]=HideCalculate(BaseData[i],Temp);
			i++;
			Temp=((HideData[j]&56)>>3)<<5;		//7
			BaseData[i]=HideCalculate(BaseData[i],Temp);
			i++;
			Temp=(HideData[j]&7)<<5;			//8
			BaseData[i]=HideCalculate(BaseData[i],Temp);
			j++;
		}

		BaseFile.Close();
		HideFile.Close();
		
		CFile file;
		file.Open("融合图像.bmp",CFile::modeCreate|CFile::modeReadWrite);
		file.Write(BaseData,BaseFileLen);
		file.Close();
		AfxMessageBox("信息隐藏完毕!");
		
		if(BaseData!=NULL)
			delete BaseData;
		if(HideData!=NULL)
			delete HideData;
	}		
}

void CDataHideInBMPBZDlg::OnBasebmpResume() 
{
	// TODO: Add your control notification handler code here
	CFileDialog dlg(TRUE,"bmp","*.bmp",OFN_HIDEREADONLY|OFN_OVERWRITEPROMPT,"载体位图文件(*.bmp)|*.bmp||",NULL);
	if(dlg.DoModal()==IDOK)
	{
		m_bBaseBMPResume=true;
		m_sCarrierFileResume=dlg.GetPathName();
		GetDlgItem(IDC_BASEBMP_RESUME)->SetWindowText(m_sCarrierFileResume);

	}
	else
		m_bBaseBMPResume=false;
	GetDlgItem(IDC_RESUMEDATA)->EnableWindow(m_bBaseBMPResume && m_bBasefile);
}

void CDataHideInBMPBZDlg::OnBasefile() 
{
	// TODO: Add your control notification handler code here
	CFileDialog dlg(TRUE,"bmp","*.bmp",OFN_HIDEREADONLY|OFN_OVERWRITEPROMPT,"原始文件(*.bmp)|*.bmp||",NULL);
	if(dlg.DoModal()==IDOK)
	{
		m_bBasefile=true;
		m_sBaseFile=dlg.GetPathName();
		GetDlgItem(IDC_BASEFILE)->SetWindowText(m_sBaseFile);
	}
	else
		m_bBasefile=false;
	GetDlgItem(IDC_RESUMEDATA)->EnableWindow(m_bBaseBMPResume && m_bBasefile);
}

void CDataHideInBMPBZDlg::OnResumedata() 
{
	// TODO: Add your control notification handler code here
	CFile BaseFile;
	CFile CarrierFile;
	DWORD BaseFileLen;
	DWORD CarrierFileLen;
	
	unsigned char* BaseData;
	unsigned char* CarrierData;
	
	if(m_bBaseBMPResume==true && m_bBasefile==true)
	{
		CarrierFile.Open(m_sCarrierFileResume,CFile::modeReadWrite);
		CarrierFileLen=CarrierFile.GetLength();
		BaseFile.Open(m_sBaseFile,CFile::modeReadWrite);
		BaseFileLen=BaseFile.GetLength();

		if(BaseFileLen!=CarrierFileLen)
		{
			AfxMessageBox("选取的不是充作载体的原始文件!");
			CarrierFile.Close();
			BaseFile.Close();
			return;
		}
		
		CarrierData=new unsigned char[CarrierFileLen];
		CarrierFile.Read(CarrierData,CarrierFileLen);

		BaseData=new unsigned char[CarrierFileLen];
		BaseFile.Read(BaseData,CarrierFileLen);

		if(CarrierData[28]!=24)
		{
			AfxMessageBox("载体文件格式错误!");
			CarrierFile.Close();
			BaseFile.Close();
			if(CarrierData!=NULL)
				delete CarrierData;
			if(BaseData!=NULL)
				delete BaseData;
			return;
		}
		if(BaseData[28]!=24)
		{
			AfxMessageBox("原始文件格式错误!");
			CarrierFile.Close();
			BaseFile.Close();
			if(CarrierData!=NULL)
				delete CarrierData;
			if(BaseData!=NULL)
				delete BaseData;
			return;
		}

		unsigned char Temp=0;
		DWORD j=0;
		for(DWORD i=54;i<CarrierFileLen;i++)
		{
			Temp=(ShowCalculate(CarrierData[i],BaseData[i])&7)<<5;
			i++;
			Temp|=(ShowCalculate(CarrierData[i],BaseData[i])&7)<<2;
			i++;
			Temp|=(ShowCalculate(CarrierData[i],BaseData[i])&6)>>1;
			CarrierData[j]=Temp;
			j++;
			Temp=(ShowCalculate(CarrierData[i],BaseData[i])&1)<<7;
			i++;
			Temp|=(ShowCalculate(CarrierData[i],BaseData[i])&7)<<4;
			i++;
			Temp|=(ShowCalculate(CarrierData[i],BaseData[i])&7)<<1;
			i++;
			Temp|=(ShowCalculate(CarrierData[i],BaseData[i])&4)>>2;
			CarrierData[j]=Temp;
			j++;
			Temp=(ShowCalculate(CarrierData[i],BaseData[i])&3)<<6;
			i++;
			Temp|=(ShowCalculate(CarrierData[i],BaseData[i])&7)<<3;
			i++;
			Temp|=ShowCalculate(CarrierData[i],BaseData[i])&7;
			CarrierData[j]=Temp;
			j++;
		}
		BaseFile.Close();
		CarrierFile.Close();
		j=0;
		CString FileName="";
		while(true)
		{
			if(CarrierData[j]=='*')
			{
				j++;
				break;
			}
			else
			{
				FileName+=CString(CarrierData[j]);
				j++;
			}
		}
		CString FileLen="";
		while(true)
		{
			if(CarrierData[j]=='*')
			{
				j++;
				break;
			}
			else
			{
				FileLen+=CString(CarrierData[j]);
				j++;
			}
		}
		BaseFileLen=atoi(FileLen);

		CFile file;
		file.Open(FileName,CFile::modeCreate|CFile::modeReadWrite);
		file.Write(CarrierData+j,BaseFileLen);
		file.Close();
		AfxMessageBox("信息恢复完毕!");

		if(BaseData!=NULL)
			delete BaseData;
		if(CarrierData!=NULL)
			delete CarrierData;
	}	
}