VC++信息安全编程（9）基于24位bmp位图的信息隐藏
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。
我们进行信息交换的时候，需要保证数据的安全，所以需要进行适当的信息隐藏。
我们发送一个图片。但是图片里面隐含的加密信息，是就是信息隐藏，只有专属工具能够读出。
所以信息隐藏技术很重要。针对信息安全。
我们来实现一个案例代码。
ＢＭＰ图信息隐藏头文件，请见代码分析
// BMPHider.h: interface for the CBMPHider class.
//
//
#if !defined(AFX_BMPHIDER_H__6287D87F_F0AA_4D0C_9502_4674B639CBB5__INCLUDED_)
#define AFX_BMPHIDER_H__6287D87F_F0AA_4D0C_9502_4674B639CBB5__INCLUDED_
#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
#include
using namespace std;
class CBMPHider
{
public:
CBMPHider();
virtual ~CBMPHider();
public:
int m_BitCount; //位图的图像位数
WORD * m_pWordData;
CPalette m_Palette;
unsigned char *m_pDib, *m_pDibBits;
unsigned char *m_pOldDibShow;
DWORD m_dwDibSize;
BITMAPINFOHEADER *m_pBIH;
RGBQUAD *m_pPalette;
int m_nPaletteEntries;
UINT bitmap_size;
UINT embfile_size;
unsigned char *p; //指向宿主图像数据
int tag; //此tag用以标记打开的图像中是否含有隐藏信息0：无 else：有
unsigned char *q; //指向隐藏文件数据
unsigned char *m_pFile;
public:
BOOL Draw( CDC *pDC, int nX = -1, int nY = -1, int nWidth = -1, int nHeight = -1, int Style = 1);
BOOL Save( const char *pszFilename );
BOOL Load( const char * );
void BackUpDib(); //备份图像
void Pick(); //提取图像
void Embed(); //嵌入图像
BOOL LoadEmbFile(const char *);
BOOL DrawContrast(CDC *pDC,int rect_width, int rect_height);
void SavePicked( const char *pszFilename );
};
#endif // !defined(AFX_BMPHIDER_H__6287D87F_F0AA_4D0C_9502_4674B639CBB5__INCLUDED_)
请见详细代码实现
#include "stdafx.h"
#include "BMPHider.h"
//
// Construction/Destruction
//
CBMPHider::CBMPHider()
{
m_pDib = NULL;
m_pWordData = NULL;
m_pFile = NULL;
m_pOldDibShow = NULL;
}
CBMPHider::~CBMPHider()
{
if( m_pDib != NULL )
delete [] m_pDib;
if( m_pWordData != NULL )
delete [] m_pWordData;
if (m_pFile != NULL)
delete [] m_pFile;
if (m_pOldDibShow != NULL)
delete [] m_pOldDibShow;
}
BOOL CBMPHider::Load( const char *pszFilename )
{
CFile cf;
if( !cf.Open( pszFilename, CFile::modeRead ) )
return( FALSE );
DWORD dwDibSize;
dwDibSize =
cf.GetLength() - sizeof( BITMAPFILEHEADER );
unsigned char *pDib;
pDib = new unsigned char [dwDibSize];
if( pDib == NULL )
return( FALSE );
BITMAPFILEHEADER BFH;
try
{
if( cf.Read( &BFH, sizeof( BITMAPFILEHEADER ) )
!= sizeof( BITMAPFILEHEADER ) ||
BFH.bfType != 'MB' ||
cf.Read( pDib, dwDibSize ) != dwDibSize )
{
delete [] pDib;
return( FALSE );
}
}
catch( CFileException *e )
{
e->Delete();
delete [] pDib;
return( FALSE );
}
cf.Close();
if( m_pDib != NULL )
delete m_pDib;
if (BFH.bfReserved1 != 0) //含有隐藏信息，保存其大小
{
if (BFH.bfReserved2 == 0)
embfile_size = BFH.bfReserved1;
else
embfile_size = BFH.bfReserved1 + 65535;
}
m_pDib = pDib;
m_dwDibSize = dwDibSize;
m_pBIH = (BITMAPINFOHEADER *) m_pDib;
m_pPalette =(RGBQUAD *) &m_pDib[sizeof(BITMAPINFOHEADER)];
m_nPaletteEntries = 1 << m_pBIH->biBitCount;
if( m_pBIH->biBitCount > 8 )
m_nPaletteEntries = 0;
else if( m_pBIH->biClrUsed != 0 )
m_nPaletteEntries = m_pBIH->biClrUsed;
m_pDibBits = &m_pDib[sizeof(BITMAPINFOHEADER)+
m_nPaletteEntries*sizeof(RGBQUAD)];
if( m_Palette.GetSafeHandle() != NULL )
m_Palette.DeleteObject();
if( m_nPaletteEntries != 0 )
{
LOGPALETTE *pLogPal = (LOGPALETTE *) new char
[sizeof(LOGPALETTE)+
m_nPaletteEntries*sizeof(PALETTEENTRY)];
if( pLogPal != NULL )
{
pLogPal->palVersion = 0x300;
pLogPal->palNumEntries = m_nPaletteEntries;
for( int i=0; ipalPalEntry[i].peRed =
m_pPalette[i].rgbRed;
pLogPal->palPalEntry[i].peGreen =
m_pPalette[i].rgbGreen;
pLogPal->palPalEntry[i].peBlue =
m_pPalette[i].rgbBlue;
}
m_Palette.CreatePalette( pLogPal );
delete [] pLogPal;
}
}
m_BitCount = 24; //24位位图
p = m_pDibBits; //指向位图数据的指针，用来执行处理操作用
bitmap_size = m_dwDibSize - (m_pDibBits - m_pDib);//真正的位图数据的大小（即除头结构外）
tag = BFH.bfReserved1;
return( TRUE );
}
BOOL CBMPHider::Save( const char *pszFilename ) //保存含有隐藏信息的bmp
{
if( m_pDib == NULL )
return( FALSE );
CFile cf;
if( !cf.Open( pszFilename,
CFile::modeCreate | CFile::modeWrite ) )
return( FALSE );
try
{
BITMAPFILEHEADER BFH;
memset( &BFH, 0, sizeof( BITMAPFILEHEADER ) );
BFH.bfType = 'MB';
BFH.bfSize = sizeof( BITMAPFILEHEADER ) + m_dwDibSize;
BFH.bfOffBits = sizeof( BITMAPFILEHEADER ) +
sizeof( BITMAPINFOHEADER ) +
m_nPaletteEntries * sizeof( RGBQUAD );
if (embfile_size <= 65535)
//由于bfReserved1是unsigned short型的，大小可能不能满足要求,可能要用到reserved2
BFH.bfReserved1 = embfile_size;
else
{
BFH.bfReserved1 = embfile_size - 65535;
BFH.bfReserved2 = 1; //标记
}
cf.Write( &BFH, sizeof( BITMAPFILEHEADER ) );
cf.Write( m_pDib, m_dwDibSize );
}
catch( CFileException *e )
{
e->Delete();
return( FALSE );
}
return( TRUE );
}
BOOL CBMPHider::Draw( CDC *pDC, int nX, int nY, int nWidth, int nHeight, int Style )
{
if( m_pDib == NULL )
return( FALSE );
long vWidth = m_pBIH->biWidth;
if( nWidth == -1 )
nWidth = m_pBIH->biWidth;
if( nHeight == -1 )
nHeight = m_pBIH->biHeight;
if (Style)
{
StretchDIBits( pDC->m_hDC, nX, nY,
nWidth, nHeight,
0, 0,
m_pBIH->biWidth, m_pBIH->biHeight,
m_pDibBits,
(BITMAPINFO *) m_pBIH,
BI_RGB, SRCCOPY );
}
else
{
SetDIBitsToDevice( pDC->m_hDC, nX, nY,
m_pBIH->biWidth, m_pBIH->biHeight,
0, 0,
0, m_pBIH->biHeight,
m_pDibBits,
(BITMAPINFO *) m_pBIH,
BI_RGB);
}
return( TRUE );
}
BOOL CBMPHider::LoadEmbFile(const char * pszFilename)
{
CFile cf;
if( !cf.Open( pszFilename, CFile::modeRead ) )
return( FALSE );
DWORD dwFileSize;
dwFileSize = cf.GetLength();
embfile_size = dwFileSize;
unsigned char *pFile;
pFile = new unsigned char [dwFileSize];
cf.Read( pFile, dwFileSize ); //将文件中内容读入数组，解下来就开始嵌入操作
m_pFile = pFile;
q = pFile; //记录下位置
return true;
}
void CBMPHider::Embed()//嵌入
{
unsigned char bmdata;//bitmap data
unsigned char efdata;//embeddedfile data
int t = 7;
int x[8];
int s[8];
int last_bit; //记录字节最低位本来的bit
for(UINT i1 = 0, i2 = 0; i1 <= bitmap_size - 1, i2 <= embfile_size - 1; i1++)
{
bmdata = *p;
for (int j = 0; j <= 7; j++) //计算各bit位
{
x[j] = bmdata & 1;
bmdata >>= 1;
}
last_bit = x[0];
x[0] = x[1] ^ x[2] ^ x[3] ^ x[4] ^ x[5] ^ x[6] ^ x[7];
if (t == 7) //宿主图片每走过八个字节，计算一次s[]
{
efdata = *q;
for (j = 0; j <= 7; j++)
{
s[j] = efdata & 1;
efdata >>= 1;
}
}
x[0] ^= s[t];//隐藏信息
if (last_bit == 0) //嵌入隐藏信息
{
*p |= x[0];
}
else
{
*p &= 254 + x[0];
}
p++;
t--;
if (t == -1) //需要计算一次s[]
{
t = 7;
q++;
i2++;
}
}
}
void CBMPHider::Pick()//提取
{
m_pFile = new unsigned char [embfile_size];
unsigned char *q = m_pFile;
unsigned char bmdata;//bitmap data
int x[8];
int s[8];
int t = 7;
for (UINT i1 = 0, i2 = 0; i1 <= bitmap_size - 1, i2 <= embfile_size - 1; i1++)
{
bmdata = *p;
for (int j = 0; j <= 7; j++) //计算各bit位
{
x[j] = bmdata & 1;
bmdata >>= 1;
}
s[t] = x[0] ^ x[1] ^ x[2] ^ x[3] ^ x[4] ^ x[5] ^ x[6] ^ x[7];
t--;
if (t == -1) //s[7]到s[0]组成一个字节
{
*q = s[7] * 128 + s[6] * 64 + s[5] * 32 + s[4] * 16 +
s[3] * 8 + s[2] * 4 + s[1] * 2 + s[0];
t = 7;
i2++;
q++;
}
p++;
}
}
void CBMPHider::SavePicked( const char *pszFilename )
{
CFile cf;
cf.Open( pszFilename, CFile::modeCreate | CFile::modeWrite );
cf.Write( m_pFile, embfile_size );
}
void CBMPHider::BackUpDib()
{
m_pOldDibShow = new unsigned char [bitmap_size];
::CopyMemory(m_pOldDibShow, m_pDibBits, bitmap_size); //将原始的数据单独保存以便对比显示
}
BOOL CBMPHider::DrawContrast(CDC *pDC, int rect_width, int rect_height)
{ //看原图，如果容纳得下两个图，则不要压缩，否则要压缩
if (m_pOldDibShow == NULL)
return FALSE;
if (rect_width >= 2*m_pBIH->biWidth + 30 && rect_height >= m_pBIH->biHeight)
{
StretchDIBits( pDC->m_hDC, 0, 0,
m_pBIH->biWidth, m_pBIH->biHeight,
0, 0,
m_pBIH->biWidth, m_pBIH->biHeight,
m_pOldDibShow,
(BITMAPINFO *) m_pBIH,
BI_RGB, SRCCOPY ); // 原图
StretchDIBits( pDC->m_hDC, m_pBIH->biWidth+30, 0,
m_pBIH->biWidth, m_pBIH->biHeight,
0, 0,
m_pBIH->biWidth, m_pBIH->biHeight,
m_pDibBits,
(BITMAPINFO *) m_pBIH,
BI_RGB, SRCCOPY ); // 嵌入隐藏信息的图
}
else
{
int scale_i = m_pBIH->biWidth * 5 / (rect_width*2);
int scale_j = m_pBIH->biHeight / rect_height;
if (scale_i < scale_j)
scale_i = scale_j;
StretchDIBits( pDC->m_hDC, 0, 0,
m_pBIH->biWidth / scale_i, m_pBIH->biHeight / scale_i,
0, 0,
m_pBIH->biWidth, m_pBIH->biHeight,
m_pOldDibShow,
(BITMAPINFO *) m_pBIH,
BI_RGB, SRCCOPY ); // 原图
StretchDIBits( pDC->m_hDC, m_pBIH->biWidth / scale_i+30, 0,
m_pBIH->biWidth / scale_i, m_pBIH->biHeight / scale_i,
0, 0,
m_pBIH->biWidth, m_pBIH->biHeight,
m_pDibBits,
(BITMAPINFO *) m_pBIH,
BI_RGB, SRCCOPY ); // 嵌入隐藏信息的图
}
return TRUE;
} 具体代码调用实现
#include "stdafx.h"
#include "DataHideInBMP.h"
#include "DataHideInBMPDoc.h"
#include "DataHideInBMPView.h"
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
/
// CDataHideInBMPView
IMPLEMENT_DYNCREATE(CDataHideInBMPView, CView)
BEGIN_MESSAGE_MAP(CDataHideInBMPView, CView)
//{{AFX_MSG_MAP(CDataHideInBMPView)
ON_COMMAND(ID_NORMAL, OnNormal)
ON_COMMAND(ID_STRETCH, OnStretch)
ON_COMMAND(ID_FILE_OPEN, OnFileOpen)
ON_COMMAND(ID_EMBED, OnEmbed)
ON_UPDATE_COMMAND_UI(ID_EMBED, OnUpdateEmbed)
ON_COMMAND(ID_PICK, OnPick)
ON_UPDATE_COMMAND_UI(ID_PICK, OnUpdatePick)
//}}AFX_MSG_MAP
// Standard printing commands
ON_COMMAND(ID_FILE_PRINT, CView::OnFilePrint)
ON_COMMAND(ID_FILE_PRINT_DIRECT, CView::OnFilePrint)
ON_COMMAND(ID_FILE_PRINT_PREVIEW, CView::OnFilePrintPreview)
END_MESSAGE_MAP()
/
// CDataHideInBMPView construction/destruction
CDataHideInBMPView::CDataHideInBMPView()
{
// TODO: add construction code here
ImageStyle = 0;
have_open_a_file = false;
embed = false;
pick = false;
show_contrast = false;
}
CDataHideInBMPView::~CDataHideInBMPView()
{
}
BOOL CDataHideInBMPView::PreCreateWindow(CREATESTRUCT& cs)
{
// TODO: Modify the Window class or styles here by modifying
// the CREATESTRUCT cs
WNDCLASSEX wndcls;
wndcls.cbSize=sizeof(WNDCLASSEX);
HINSTANCE hinst=AfxGetInstanceHandle();
if(CView::PreCreateWindow(cs)&&cs.lpszClass!=NULL)
{
HBRUSH hbkbrush=CreateSolidBrush(RGB(0,0,0));
if(!GetClassInfoEx(hinst,cs.lpszClass,&wndcls))
return FALSE;
UnregisterClass(cs.lpszClass,hinst);
wndcls.hbrBackground=hbkbrush;
RegisterClassEx(&wndcls);
return TRUE;
}
else
return FALSE;
return CView::PreCreateWindow(cs);
}
/
// CDataHideInBMPView drawing
void CDataHideInBMPView::OnDraw(CDC* pDC)
{
CDataHideInBMPDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
// TODO: add draw code for native data here
RECT Rect;
GetClientRect( &Rect );
if (!show_contrast)
m_BMPHider.Draw( pDC, 0, 0, Rect.right, Rect.bottom, ImageStyle );
else
{
m_BMPHider.DrawContrast(pDC, Rect.right, Rect.bottom);
pDC->SetBkColor((0,0,0));
pDC->SetTextColor((255,255,255));
pDC->TextOut(0, Rect.bottom-30, "左图为原始图，右图为嵌入了隐藏信息的图");
}
}
/
// CDataHideInBMPView printing
BOOL CDataHideInBMPView::OnPreparePrinting(CPrintInfo* pInfo)
{
// default preparation
return DoPreparePrinting(pInfo);
}
void CDataHideInBMPView::OnBeginPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/)
{
// TODO: add extra initialization before printing
}
void CDataHideInBMPView::OnEndPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/)
{
// TODO: add cleanup after printing
}
/
// CDataHideInBMPView diagnostics
#ifdef _DEBUG
void CDataHideInBMPView::AssertValid() const
{
CView::AssertValid();
}
void CDataHideInBMPView::Dump(CDumpContext& dc) const
{
CView::Dump(dc);
}
CDataHideInBMPDoc* CDataHideInBMPView::GetDocument() // non-debug version is inline
{
ASSERT(m_pDocument->IsKindOf(RUNTIME_CLASS(CDataHideInBMPDoc)));
return (CDataHideInBMPDoc*)m_pDocument;
}
#endif //_DEBUG
/
// CDataHideInBMPView message handlers
void CDataHideInBMPView::OnNormal()
{
// TODO: Add your command handler code here
ImageStyle = 0;
CMenu *pMnu = AfxGetMainWnd()->GetMenu( );
pMnu->CheckMenuItem(ID_STRETCH,MF_UNCHECKED);
pMnu->CheckMenuItem(ID_NORMAL,MF_CHECKED);
InvalidateRect( NULL, TRUE );
UpdateWindow();
}
void CDataHideInBMPView::OnStretch()
{
// TODO: Add your command handler code here
ImageStyle = 1;
CMenu *pMnu = AfxGetMainWnd()->GetMenu( );
pMnu->CheckMenuItem(ID_STRETCH,MF_CHECKED);
pMnu->CheckMenuItem(ID_NORMAL,MF_UNCHECKED);
InvalidateRect( NULL, TRUE );
UpdateWindow();
}
void CDataHideInBMPView::OnFileOpen()
{
// TODO: Add your command handler code here
show_contrast = false; //非对比显示
static char szFilter[] = "BMP Files(*.BMP)|*.BMP||";
CFileDialog FileDlg( TRUE, NULL, NULL,
OFN_HIDEREADONLY, szFilter );
if( FileDlg.DoModal() == IDOK &&
m_BMPHider.Load( FileDlg.GetPathName() ) )
{
InvalidateRect( NULL, TRUE );
UpdateWindow();
have_open_a_file=true;
if (m_BMPHider.tag == 0)//该图无隐藏信息
{
embed = true;
pick = false; //菜单亮暗控制
}//
else
{
embed = false;
pick = true; //菜单亮暗控制
}//
}
}
void CDataHideInBMPView::OnEmbed()
{
// TODO: Add your command handler code here
//弹出打开对话框，用户选择嵌入的文件
static char szFilter[] = "All Files(*.*)|*.*||";
CFileDialog FileDlg( TRUE, NULL, NULL,
OFN_HIDEREADONLY, szFilter );
if( FileDlg.DoModal() == IDOK &&
m_BMPHider.LoadEmbFile( FileDlg.GetPathName() ) )
{
if (m_BMPHider.bitmap_size / m_BMPHider.embfile_size < 8)
{
AfxMessageBox("文件太大，无法嵌入！");
}
else
{
show_contrast = true;
m_BMPHider.BackUpDib(); //图片原始数据备份供对比显示
m_BMPHider.Embed(); //嵌入
Invalidate(true);//刷屏，显示加入隐藏信息后的图像
static char szFilter[] = "BMP Files(*.BMP)|*.BMP||";
CFileDialog FileDlg( FALSE, "bmp", NULL, //保存
OFN_HIDEREADONLY|OFN_OVERWRITEPROMPT, szFilter );
if( FileDlg.DoModal() == IDOK )
{
m_BMPHider.Save( FileDlg.GetPathName() );
}
embed = false;
}
}
}
void CDataHideInBMPView::OnUpdateEmbed(CCmdUI* pCmdUI)
{
// TODO: Add your command update UI handler code here
pCmdUI->Enable(embed);
}
void CDataHideInBMPView::OnPick()
{
// TODO: Add your command handler code here
//提取完毕，弹出保存对话框，用户进行保存
static char szFilter[] = "All Files(*.*)|*.*||";
CFileDialog FileDlg( FALSE, "", NULL, //保存
OFN_HIDEREADONLY|OFN_OVERWRITEPROMPT, szFilter );
if (FileDlg.DoModal() == IDOK)
{
m_BMPHider.Pick();
m_BMPHider.SavePicked(FileDlg.GetPathName());
pick = false;
}
}
void CDataHideInBMPView::OnUpdatePick(CCmdUI* pCmdUI)
{
// TODO: Add your command update UI handler code here
pCmdUI->Enable(pick);
}