Image Steganalysis Image Steganography

Transcription

1 //Joshua Tracy #include <opencv2/core/core.hpp> #include <opencv2/highgui/highgui.hpp> #include "opencv2/opencv.hpp" #include <stdlib.h> #include <iostream> #include <stdint.h> #include <time.h> using namespace cv; int main(int argc, char* argv[]) Mat hidden = imread(argv[1]); int w1, h1; w1 = hidden.cols; h1 = hidden.rows; Image Steganalysis //******LSB ENhancment******************** for (int i = 0; i < h1; i++) for (int j = 0; j < w1*3 ; j++) int lsb = hidden.at<char>(i, j); lsb = lsb & 1; if (lsb) hidden.at<char>(i, j) = 255; hidden.at<char>(i, j) = 0; imwrite(argv[2], hidden); return 0; //Joshua Tracy #include <opencv2/core/core.hpp> #include "opencv2/opencv.hpp" #include <opencv2/highgui/highgui.hpp> #include <iostream> #include <stdint.h> using namespace cv; using namespace std; char ExtractChar(Mat coverimage, int i, int j) Image Steganography

2 int bit; int red = coverimage.at<char>(i, j); int green = coverimage.at<char>(i, j + 1); int blue = coverimage.at<char>(i, j + 2); j += 3; if (j / 3 == coverimage.cols) int red2 = coverimage.at<char>(i, j); int green2 = coverimage.at<char>(i, j + 1); int blue2 = coverimage.at<char>(i, j + 2); // convert the two pixels to a character unsigned int T = 0; T += (red & 1); T += (2 * (green & 1)); T += (4 * (blue & 1)); bit = blue & 2; if (bit > 0) bit = 1; bit = 0; T += (8 * bit); T += (16 * (red2 & 1)); T += (32 * (green2 & 1)); T += (64 * (blue2 & 1)); bit = blue2 & 2; if (bit > 0) bit = 1; bit = 0; T += (128 * bit); char c = (char)t; return c; void encode(char* file, char* image, char* outputfile) Mat coverimage = imread(image, CV_LOAD_IMAGE_UNCHANGED); //cvtcolor(coverimage, coverimage, CV_RGBA2BGRA); if (!coverimage.data) cout << "Could not read one of the immages " << endl; int MaxNumberOfPixels = coverimage.rows * coverimage.cols; int MaxCharsToEncode = (int)(0.5 * MaxNumberOfPixels); int NumberOfCharsToEncode; int FileNameSize = strlen(file) + 1; char * FileName = new char[filenamesize]; strcpy(filename, file);

3 int filesize = 0; char* StegoIdentifierString = "JTstego"; FILE* fp; fp = fopen(file, "rb"); if (!fp) cout << "Error: unable to read file " << file << " for text input!" << endl; NumberOfCharsToEncode = FileNameSize + strlen(stegoidentifierstring) + 2 // indicate length of filename + 4; // indicate length of data unsigned char *CharsToEncode = new unsigned char[numberofcharstoencode]; if (NumberOfCharsToEncode > MaxCharsToEncode) cout << "Error: File is too small to even encode file information!\n" << " Terminating encoding.\n"; while (!feof(fp)) char c; fread(&c, 1, 1, fp); filesize++; filesize--; MaxCharsToEncode -= NumberOfCharsToEncode; if (filesize > MaxCharsToEncode) filesize = MaxCharsToEncode; cout << "Warning: Input file exceeds encoding capacity of the image\n" << " File will be truncated.\n"; fclose(fp); // create this "file header" string int k = 0; // this part gives the length of the filename while (k < strlen(stegoidentifierstring)) CharsToEncode[k] = StegoIdentifierString[k]; k++;

4 int TempInt = FileNameSize % 256; CharsToEncode[k] = (unsigned char)tempint; k++; TempInt = FileNameSize - TempInt; if (TempInt < 0) TempInt = 0; TempInt = TempInt / 256; CharsToEncode[k] = (unsigned char)tempint; k++; // this part hides the filename int j = 0; while (j < FileNameSize) CharsToEncode[k] = FileName[j]; k++; j++; // this part gives the length of the hidden data int TempIntOriginal = filesize; TempInt = filesize % 256; CharsToEncode[k] = (unsigned char)tempint; k++; TempIntOriginal -= TempInt; if (TempIntOriginal > 0) TempInt = TempIntOriginal % 65536; CharsToEncode[k] = (unsigned char)(tempint / 256); k++; TempIntOriginal -= TempInt;// *256; CharsToEncode[k] = 0; k++; if (TempIntOriginal > 0) TempInt = TempIntOriginal % ; CharsToEncode[k] = (unsigned char)(tempint / 65536); k++; TempIntOriginal -= TempInt;// *65536; CharsToEncode[k] = 0; k++; if (TempIntOriginal > 0) TempInt = TempIntOriginal % ; CharsToEncode[k] = (unsigned char)(tempint / ); k++; TempIntOriginal -= TempInt;// * ;

5 CharsToEncode[k] = 0; k++; k = 0; int i = 0; j = 0; fp = fopen(file, "rb"); while (!feof(fp) && k < NumberOfCharsToEncode) // decompose the character unsigned int T = (unsigned int)charstoencode[k]; int R1 = T % 2; T = (T - R1) / 2; int G1 = T % 2; T = (T - G1) / 2; int B1 = T % 2; T = (T - B1) / 2; int A1 = T % 2; T = (T - A1) / 2; int R2 = T % 2; T = (T - R2) / 2; int G2 = T % 2; T = (T - G2) / 2; int B2 = T % 2; T = (T - B2) / 2; int A2 = T % 2; T = (T - A2) / 2; int red = coverimage.at<char>(i, j); int green = coverimage.at<char>(i, j+1); int blue = coverimage.at<char>(i, j+2); red = red -(red &1) + R1; green = green - (green & 1) + G1; blue = blue - (blue & 3) + B1 + (A1*2); coverimage.at<char>(i, j) = red; coverimage.at<char>(i, j + 1) = green; coverimage.at<char>(i, j + 2) = blue ; j+=3; if (j/3 == coverimage.cols) red = coverimage.at<char>(i, j); green = coverimage.at<char>(i, j + 1);

6 blue = coverimage.at<char>(i, j + 2); red = red - (red & 1) + R2; green = green - (green & 1) + G2; blue = blue - (blue & 3) + B2 + (A2 * 2); coverimage.at<char>(i, j) = red; coverimage.at<char>(i, j + 1) = green; coverimage.at<char>(i, j + 2) = blue; j+=3; k++; if (j/3 == coverimage.cols) // encode the actual data k = 0; while (!feof(fp) && k < 6 * filesize) char c; fread(&c, 1, 1, fp); // decompose the character unsigned int T = (unsigned int)c; int R1 = T % 2; T = (T - R1) / 2; int G1 = T % 2; T = (T - G1) / 2; int B1 = T % 2; T = (T - B1) / 2; int A1 = T % 2; T = (T - A1) / 2; int R2 = T % 2; T = (T - R2) / 2; int G2 = T % 2; T = (T - G2) / 2; int B2 = T % 2; T = (T - B2) / 2; int A2 = T % 2; T = (T - A2) / 2; int red = coverimage.at<char>(i, j); int green = coverimage.at<char>(i, j + 1); int blue = coverimage.at<char>(i, j + 2); red = red - (red & 1) + R1; green = green - (green & 1) + G1;

7 blue = blue - (blue & 3) + B1 + (A1 * 2); coverimage.at<char>(i, j) = red; coverimage.at<char>(i, j + 1) = green; coverimage.at<char>(i, j + 2) = blue; j += 3; if (j / 3 == coverimage.cols) red = coverimage.at<char>(i, j); green = coverimage.at<char>(i, j + 1); blue = coverimage.at<char>(i, j + 2); red = red - (red & 1) + R2; green = green - (green & 1) + G2; blue = blue - (blue & 3) + B2 + (A2 * 2); coverimage.at<char>(i, j) = red; coverimage.at<char>(i, j + 1) = green; coverimage.at<char>(i, j + 2) = blue; j += 3; k++; if (j / 3 == coverimage.cols) fclose(fp); imwrite(outputfile, coverimage); void decode(char* image) Mat coverimage = imread(image, CV_LOAD_IMAGE_UNCHANGED); if (!coverimage.data) cout << "Could not read the image " << endl; char* StegoIdentifierString = "JTstego"; char* ComparisonString = new char[strlen(stegoidentifierstring) + 1]; int i = 0; int j = 0; int k = 0; while (k < strlen(stegoidentifierstring)) ComparisonString[k] = ExtractChar(coverimage, i, j); while (j/3 >= coverimage.cols) j =0; i++;

8 k++; ComparisonString[k] = '\0'; if (strcmp(stegoidentifierstring, ComparisonString)) cout << "Error: No (compatible) hidden data found in image!\n"; // get the next two characters to determine file size unsigned char C1 = (unsigned char)extractchar(coverimage, i, j); unsigned char C2 = (unsigned char)extractchar(coverimage, i, j); int FileNameSize = C * C2; char* FileName = new char[filenamesize]; // read the filename k = 0; while (k < FileNameSize) FileName[k] = ExtractChar(coverimage, i, j); k++; FileName[k] = '\0'; // find the actual data size C1 = (unsigned char)extractchar(coverimage, i, j);

9 C2 = (unsigned char)extractchar(coverimage, i, j); unsigned char C3 = (unsigned char)extractchar(coverimage, i, j); unsigned char C4 = (unsigned char)extractchar(coverimage, i, j); int FileSize = C1 + (256 * C2) + (65536 * C3) + ( * C4); int NumberOfCharsToEncode = FileNameSize strlen(stegoidentifierstring); if (FileSize == 0 FileNameSize == 0 NumberOfCharsToEncode == 0) cout << "No hiddent data detected. Exiting... " << endl; cout << "Hidden data detected! Outputting to file " << FileName << "... " << endl; FILE* fp; fp = fopen(filename, "wb"); if (!fp) cout << "Error: Unable to open file " << FileName << " for output!\n"; int MaxNumberOfPixels = coverimage.cols * coverimage.rows; k = 0; i = 0; j = 0; // set the starting pixel to skip the internal header j = 6 * NumberOfCharsToEncode;

10 while (k < 6 * FileSize) // read the two pixels int bit; int red = coverimage.at<char>(i, j); int green = coverimage.at<char>(i, j + 1); int blue = coverimage.at<char>(i, j + 2); j += 3; k++; if (j / 3 == coverimage.cols) int red2 = coverimage.at<char>(i, j); int green2 = coverimage.at<char>(i, j + 1); int blue2 = coverimage.at<char>(i, j + 2); j += 3; k++; if (j / 3 == coverimage.cols) // convert the two pixels to a character unsigned int T = 0; T += (red & 1); T += (2 * (green & 1)); T += (4 * (blue & 1)); bit = blue & 2; if (bit > 0) bit = 1; bit = 0; T += (8 * bit); T += (16 * (red2 & 1)); T += (32 * (green2 & 1)); T += (64 * (blue2 & 1)); bit = blue2 & 2; if (bit > 0) bit = 1; bit = 0; T += (128 * bit); char c = (char)t; fwrite(&c, 1, 1, fp); fclose(fp);

11 int main(int argc, char* argv[]) if (*argv[1]=='e'&&argc==5) encode(argv[2], argv[3], argv[4]); if (*argv[1] == 'd'&&argc == 3) decode(argv[2]); //waitkey(0); return 0;