Stéganographie avec du bruit et de l'aléatoire
Bonjour, je n'arrive pas à retrouver le message original avec mon décodeur.
voici le code:
Code:
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#include <cv.h> // open cv general include file
#include <highgui.h> // open cv GUI include file
#include <iostream>
#include <fstream>
#include <cstring>
#include <sstream>
#include <stdlib.h>
using namespace cv; // OpenCV API is in the C++ "cv" namespace
using namespace std;
unsigned long
djb2(unsigned char *str)
{
unsigned long hash = 5381;
int c;
while (c = *str++)
hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
return hash;
}
int main(int argc, char** argv )
{
Mat encodedImg; // inputobject
Mat originalImg; //original object
Mat outputImg(Size(640,480),CV_8U);
Mat invertedImg;
Mat noisecarrierImg;
std::vector<int>params;
// check that command line arguments are provided and image reads in OK
if(argc != 4)
cout<<"invalid argument"<<endl;
//prompt the user for a character string password
string password;
cout <<"Set the password:"<<endl;
cin >> password;
//hash function: transform an ascii to a 64bit integer
unsigned long b=djb2((unsigned char *)password.c_str());
//random nunmber generator seed
RNG random(b);
//generate an array structure of boolean
if((encodedImg=imread(argv[1], CV_LOAD_IMAGE_COLOR)).empty())
{
cout<<"impossible to load file"<<endl;
return 0;
}
originalImg=imread(argv[2],CV_LOAD_IMAGE_COLOR);
bool* list=new bool [3*encodedImg.rows*encodedImg.cols];
for(int a=0; a<encodedImg.rows*encodedImg.cols*3; a++)
{
list[a] = false;
}
//generate noise carrier image
noisecarrierImg=encodedImg.clone();
for (int k=0; k<3; k++)
{
for(int i=0; i<encodedImg.rows; i++)
{
for(int j=0; j<encodedImg.cols; j++)
{
noisecarrierImg.at<Vec3b>(i,j)=originalImg.at<Vec3b>(i,j)[k]+random.gaussian(15.0);
}
}
}
//select a random location in the colored carrier image
for(int i=0; i<encodedImg.rows; i++)
{
for(int j=0; j<encodedImg.cols; j++)
{
int r;
int c;
int g;
do
{
c=random(encodedImg.cols);
r=random(encodedImg.rows);
g=random(3);
}
while(list[(r*encodedImg.cols + c)*3 + g] && encodedImg.at<Vec3b>(r,c)[g] == 255 );
list[(r*encodedImg.cols + c)*3 + g]=true;
outputImg.at<uchar>(i,j)=(encodedImg.at<Vec3b>(r,c)[g] -noisecarrierImg.at<Vec3b>(r,c)[g])*255);
}
}
invertedImg=outputImg.clone();
for(int i=0; i<outputImg.rows; i++)
{
for(int j=0; j<outputImg.cols; j++)
{
if(outputImg.at<uchar>(i,j)==0)
outputImg.at<uchar>(i,j)=255;
if(outputImg.at<uchar>(i,j)==1)
outputImg.at<uchar>(i,j)=0;
}
}
imwrite(argv[3], invertedImg, params);
} |
