commit 0318bbbf335d58d735a228a65d85315d7f1e5441
Author: BlackLight <blacklight@autistici.org>
Date: Mon Jul 13 18:55:12 2009 +0200
lulz
diff --git a/AUTHORS b/AUTHORS
new file mode 100644
index 0000000..d912fda
--- /dev/null
+++ b/AUTHORS
@@ -0,0 +1,4 @@
+Author: BlackLight
+Mail: blacklight@autistici.org
+Web: http://0x00.ath.cx | http://blacklight.gotdns.org
+
diff --git a/BUGS b/BUGS
new file mode 100644
index 0000000..bc4ae0c
--- /dev/null
+++ b/BUGS
@@ -0,0 +1,5 @@
+Sometimes the last two bytes or the last byte of the text is truncated
+in decode operations. I don't know if it's my fault, as this bug seems
+to happen almost in random strings of random length, or zLib's fault.
+I'll try to fix anyway.
+
diff --git a/INSTALL b/INSTALL
new file mode 100644
index 0000000..5c226d0
--- /dev/null
+++ b/INSTALL
@@ -0,0 +1,18 @@
+* PREREQUISITES
+
+> You must have CImg libraries <http://cimg.sourceforge.net/> installed on your
+ system in order to compile and use Jastegal. These libraries are used for a
+ high-level wrapping of image managing.
+
+> You also must have zlib installed on your system. zlib is installed almost
+ anywhere, and it's use by Jastemal for compression/uncompression operations.
+
+
+* INSTALLATION
+
+> To install Jastegal on your system you need, of course, g++ and gmake already
+ installed. Then, just type:
+
+ $ make
+ % make install
+
diff --git a/LICENCE b/LICENCE
new file mode 100644
index 0000000..5c5072d
--- /dev/null
+++ b/LICENCE
@@ -0,0 +1,30 @@
+The files in this directory and elsewhere which refer to this LICENCE
+file are part of Jastegal (Just Another Steganography algorithm)
+
+ Copyright (C) 2009 BlackLight
+
+Jastegal is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3 or (at your option) any later
+version.
+
+Jastegal is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License along
+with Jastegal; if not, write to the Free Software Foundation, Inc.,
+59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+
+As a special exception, if other files instantiate templates or use
+macros or inline functions from these files, or you compile these
+files and link them with other works to produce a work based on these
+files, these files do not by themselves cause the resulting work to be
+covered by the GNU General Public License. However the source code for
+these files must still be made available in accordance with section (3)
+of the GNU General Public License.
+
+This exception does not invalidate any other reasons why a work based on
+this file might be covered by the GNU General Public License.
+
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..ce6128b
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,30 @@
+CXX=g++
+CFLAGS=-Wall -pedantic
+LDFLAGS=-lX11 -lpthread -lm -lz
+INSTALLDIR=/usr/local
+
+NAME=jastegal
+FILES=utils.o jastegal.o encode.o decode.o compress.o
+
+ifeq (${DEBUG},1)
+ CFLAGS += -g3
+endif
+
+all: $(FILES)
+ ${CXX} ${LDFLAGS} -o ${NAME} ${FILES}
+
+$(FILES): $(FILES:.o=.cpp)
+ ${CXX} ${CFLAGS} -c $*.cpp
+
+install:
+ mkdir -p ${INSTALLDIR}/bin
+ install -m 0755 ${NAME} ${INSTALLDIR}/bin
+
+clean:
+ rm ${FILES}
+ rm ${NAME}
+
+uninstall:
+ rm -f ${INSTALLDIR}/bin/${NAME}
+
+
diff --git a/README b/README
new file mode 100644
index 0000000..d13390d
--- /dev/null
+++ b/README
@@ -0,0 +1,21 @@
+Jastegal (Just Another Steganography Algorithm) v.0.1b
+c0ded by BlackLight <blacklight@autistici.org>
+
+Usage: ./jastegal [-d|-e] <-i image file> [-o output image file] [-f file to be steganographied]
+
+-d: Perform a decoding from an image
+-e: Perform an encoding to an image
+-i: Specify the input image to be processed. In case of decoding, the content of this file will be de-steganographied,
+ while in case of encoding this is the image to steganography from
+-o: Specify the output image. This parameter is mandatory in encoding phase, as it specifies the file name containing
+ the image with the steganographied data
+-f: Specify, in encoding phase, the file containing data to be steganographied. If this option is not specified, the
+ data will be gathered via stdin
+
+Examples:
+ jastegal -e -i input_image.png -o output_image.png -f file.txt
+ This will encode the data in file.txt using input_image.png as image, and putting the output in output_image.png
+
+ jastegal -d -i input_image.png
+ This will decode the data in input_image.png to stdout
+
diff --git a/TODO b/TODO
new file mode 100644
index 0000000..49378d1
--- /dev/null
+++ b/TODO
@@ -0,0 +1,2 @@
+Support for base64 output and text cryptography (coming, I hope, *VERY* soon).
+
diff --git a/compress.cpp b/compress.cpp
new file mode 100644
index 0000000..32d201d
--- /dev/null
+++ b/compress.cpp
@@ -0,0 +1,78 @@
+/*
+ * jastegal.h
+ *
+ * The files in this directory and elsewhere which refer to this LICENCE
+ * file are part of Jastegal (Just Another Steganography algorithm)
+ *
+ * Copyright (C) 2009 BlackLight
+ *
+ * Jastegal is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 3 or (at your option) any later
+ * version.
+ *
+ * Jastegal is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with Jastegal; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * As a special exception, if other files instantiate templates or use
+ * macros or inline functions from these files, or you compile these
+ * files and link them with other works to produce a work based on these
+ * files, these files do not by themselves cause the resulting work to be
+ * covered by the GNU General Public License. However the source code for
+ * these files must still be made available in accordance with section (3)
+ * of the GNU General Public License.
+ *
+ * This exception does not invalidate any other reasons why a work based on
+ * this file might be covered by the GNU General Public License.
+ */
+
+#include <iostream>
+#include <string>
+#include <zlib.h>
+
+using namespace std;
+
+char* zCompress (char* uncompressed, unsigned int uLen, unsigned int &cLen) {
+ char *compressed = new char[uLen+10];
+
+ if (!compressed)
+ return NULL;
+
+ if (compress((Bytef*) compressed, (uLongf*) &cLen, (Bytef*) uncompressed, uLen) < 0)
+ return NULL;
+
+ return compressed;
+}
+
+char* zUncompress (char* compressed, unsigned int cLen, unsigned int &uLen) {
+ uLen = cLen;
+ int ret = 4;
+ char *uncompressed = NULL;
+
+ while ((uLen < 4000000) && (ret != Z_OK)) {
+ if (uncompressed)
+ delete [] uncompressed;
+
+ uncompressed = new char[uLen+10];
+
+ if (!uncompressed)
+ return NULL;
+
+ ret = uncompress((Bytef*) uncompressed, (uLongf*) &uLen, (Bytef*) compressed, cLen);
+
+ if (ret == Z_MEM_ERROR || ret == Z_BUF_ERROR)
+ return NULL;
+
+ if (ret != Z_OK)
+ uLen *= 2;
+ }
+
+ return uncompressed;
+}
+
diff --git a/decode.cpp b/decode.cpp
new file mode 100644
index 0000000..feab77e
--- /dev/null
+++ b/decode.cpp
@@ -0,0 +1,86 @@
+/*
+ * decode.cpp
+ *
+ * The files in this directory and elsewhere which refer to this LICENCE
+ * file are part of Jastegal (Just Another Steganography algorithm)
+ *
+ * Copyright (C) 2009 BlackLight
+ *
+ * Jastegal is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 3 or (at your option) any later
+ * version.
+ *
+ * Jastegal is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with Jastegal; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * As a special exception, if other files instantiate templates or use
+ * macros or inline functions from these files, or you compile these
+ * files and link them with other works to produce a work based on these
+ * files, these files do not by themselves cause the resulting work to be
+ * covered by the GNU General Public License. However the source code for
+ * these files must still be made available in accordance with section (3)
+ * of the GNU General Public License.
+ *
+ * This exception does not invalidate any other reasons why a work based on
+ * this file might be covered by the GNU General Public License.
+ */
+
+#include <CImg.h>
+
+#include <string>
+#include "jastegal.h"
+
+using namespace std;
+using namespace cimg_library;
+
+string steganoDecode (string inImg) {
+ CImg<u8> img(inImg.c_str());
+ rgb header[8];
+ string content;
+ unsigned int uLen, size = 0;
+
+ for (unsigned int i=0; i < 8; i++) {
+ header[i].r = img[3*i];
+ header[i].g = img[3*i + 1];
+ header[i].b = img[3*i + 2];
+ }
+
+ for (unsigned int i=0; i < 8; i++) {
+ size |= ((header[i].r & 0x3) << (i*4));
+ size |= ((header[i].b & 0x3) << ((i*4)+2));
+ }
+
+ for (unsigned int i=6*sizeof(unsigned int); i < 6*(size + sizeof(unsigned int)); i+=6) {
+ rgb couple[2];
+ u8 buf = 0;
+
+ for (unsigned int j=0; j<2; j++) {
+ couple[j].r = img[i + 3*j];
+ couple[j].g = img[i + 3*j + 1];
+ couple[j].b = img[i + 3*j + 2];
+ }
+
+ buf =
+ ( ((couple[0].r & 0x3) << 6) |
+ ((couple[0].b & 0x3) << 4) |
+ ((couple[1].r & 0x3) << 2) |
+ ((couple[1].b & 0x3)) );
+
+ content += buf;
+ }
+
+ char *uncompressed = zUncompress((char*) content.c_str(), size, uLen);
+
+ if (!uncompressed)
+ return string("");
+
+ return string(uncompressed);
+}
+
diff --git a/encode.cpp b/encode.cpp
new file mode 100644
index 0000000..0410beb
--- /dev/null
+++ b/encode.cpp
@@ -0,0 +1,120 @@
+/*
+ * encode.cpp
+ *
+ * The files in this directory and elsewhere which refer to this LICENCE
+ * file are part of Jastegal (Just Another Steganography algorithm)
+ *
+ * Copyright (C) 2009 BlackLight
+ *
+ * Jastegal is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 3 or (at your option) any later
+ * version.
+ *
+ * Jastegal is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with Jastegal; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * As a special exception, if other files instantiate templates or use
+ * macros or inline functions from these files, or you compile these
+ * files and link them with other works to produce a work based on these
+ * files, these files do not by themselves cause the resulting work to be
+ * covered by the GNU General Public License. However the source code for
+ * these files must still be made available in accordance with section (3)
+ * of the GNU General Public License.
+ *
+ * This exception does not invalidate any other reasons why a work based on
+ * this file might be covered by the GNU General Public License.
+ */
+
+#include <CImg.h>
+
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include "jastegal.h"
+
+using namespace std;
+using namespace cimg_library;
+
+int steganoEncode (string inImg, string outImg, string fname) {
+ CImg<u8> img(inImg.c_str());
+ string::iterator ch;
+ string content = fileContent(fname);
+
+ unsigned int i, j, k, cLen, size = (fname.empty()) ? content.size() : fileSize(fname);
+ char *compressed = zCompress((char*) content.c_str(), size, cLen);
+
+ cout << "Working...\n";
+
+ if (!compressed)
+ return 1;
+
+ if ((unsigned int) (6*img.dimx()*img.dimy()) <= cLen) {
+ cerr << "Error: file " << fname << " is too long to be steganographied inside image " << inImg << endl;
+ return 1;
+ }
+
+ u8 *buf = new u8[sizeof(unsigned int)];
+ memcpy (buf, &size, sizeof(unsigned int));
+
+ for (i=0; i < 6*sizeof(unsigned int); i+=6) {
+ unsigned int k = ((int) i/6);
+
+ buf[k] = (
+ ((buf[k] & 0x03) << 6) |
+ ((buf[k] & 0x0c) << 2) |
+ ((buf[k] & 0x30) >> 2) |
+ ((buf[k] & 0xc0) >> 6));
+
+ vector<u8> sizebits = bitsplit(buf[k]);
+
+ for (j=0; j < sizebits.size(); j+=2) {
+ unsigned int index;
+ u8 operand = (sizebits[j] << 1) | sizebits[j+1];
+
+ switch (j) {
+ case 0: index = i ; break;
+ case 2: index = i+2; break;
+ case 4: index = i+3; break;
+ case 6: index = i+5; break;
+ }
+
+ img[index] = ((img[index] & 0xfc) | operand);
+ }
+ }
+
+ //for (i=6*sizeof(unsigned int), ch = content.begin(); ch < content.end(); i+=6, ch++) {
+ for (i=6*sizeof(unsigned int), k=0; k < cLen; i+=6, k++) {
+ vector<u8> bits = bitsplit(compressed[k]);
+
+ for (j=0; j < bits.size(); j+=2) {
+ unsigned int index;
+ u8 operand = (bits[j] << 1) | bits[j+1];
+
+ switch (j) {
+ case 0: index=i ; break;
+ case 2: index=i+2; break;
+ case 4: index=i+3; break;
+ case 6: index=i+5; break;
+ }
+
+ img[index] = (img[index] & 0xfc) | operand;
+ }
+ }
+
+ img.save(outImg.c_str());
+ img.clear();
+
+ if (compressed)
+ delete [] compressed;
+
+ return 0;
+}
+
diff --git a/jastegal.cpp b/jastegal.cpp
new file mode 100644
index 0000000..2846354
--- /dev/null
+++ b/jastegal.cpp
@@ -0,0 +1,119 @@
+/*
+ * jastegal.cpp
+ *
+ * The files in this directory and elsewhere which refer to this LICENCE
+ * file are part of Jastegal (Just Another Steganography algorithm)
+ *
+ * Copyright (C) 2009 BlackLight
+ *
+ * Jastegal is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 3 or (at your option) any later
+ * version.
+ *
+ * Jastegal is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with Jastegal; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * As a special exception, if other files instantiate templates or use
+ * macros or inline functions from these files, or you compile these
+ * files and link them with other works to produce a work based on these
+ * files, these files do not by themselves cause the resulting work to be
+ * covered by the GNU General Public License. However the source code for
+ * these files must still be made available in accordance with section (3)
+ * of the GNU General Public License.
+ *
+ * This exception does not invalidate any other reasons why a work based on
+ * this file might be covered by the GNU General Public License.
+ */
+
+#include <CImg.h>
+
+#include <iostream>
+#include <unistd.h>
+
+#include "jastegal.h"
+
+using namespace std;
+using namespace cimg_library;
+
+int main (int argc, char **argv) {
+ int ch;
+ string inImg, outImg, fname;
+ action act = undef;
+
+ while ((ch=getopt(argc,argv,"edi:o:f:"))>0) {
+ switch (ch) {
+ case 'i':
+ inImg = string(optarg);
+ break;
+
+ case 'o':
+ outImg = string(optarg);
+ break;
+
+ case 'd':
+ if (act != undef) {
+ cerr << "Error: you can use a flag between -d (decode) and -e (encode) a time\n\n";
+ printHelp(argv[0]);
+ return 1;
+ }
+
+ act = decode;
+ break;
+
+ case 'e':
+ if (act == decode) {
+ cerr << "Error: you can use a flag between -d (decode) and -e (encode) a time\n\n";
+ printHelp(argv[0]);
+ return 1;
+ }
+
+ act = encode;
+ break;
+
+ case 'f':
+ fname = string(optarg);
+ break;
+ }
+ }
+
+ if (act == undef) {
+ cerr << "Error: you must specify an action between decoding (-d) and encoding (-e)\n\n";
+ printHelp(argv[0]);
+ return 1;
+ }
+
+ if (inImg.empty()) {
+ printHelp(argv[0]);
+ return 1;
+ }
+
+ if (act == encode) {
+ if (outImg.empty()) {
+ cerr << "Error: you must specify a file name for the output image using -o option when encoding\n\n";
+ printHelp(argv[0]);
+ return 1;
+ }
+
+ if (fname.empty())
+ cout << "Enter the input message to be steganographied [CTRL+D to end]:\n";
+
+ if (steganoEncode (inImg, outImg, fname)) {
+ cerr << "There was an unrecoverable error while processing the image. Exiting...\n";
+ return 1;
+ }
+
+ cout << "The steganographied output was successfully written to " << outImg << endl;
+ } else {
+ cout << steganoDecode(inImg) << endl;
+ }
+
+ return 0;
+}
+
diff --git a/jastegal.h b/jastegal.h
new file mode 100644
index 0000000..3a846b6
--- /dev/null
+++ b/jastegal.h
@@ -0,0 +1,73 @@
+/*
+ * jastegal.h
+ *
+ * The files in this directory and elsewhere which refer to this LICENCE
+ * file are part of Jastegal (Just Another Steganography algorithm)
+ *
+ * Copyright (C) 2009 BlackLight
+ *
+ * Jastegal is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 3 or (at your option) any later
+ * version.
+ *
+ * Jastegal is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with Jastegal; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * As a special exception, if other files instantiate templates or use
+ * macros or inline functions from these files, or you compile these
+ * files and link them with other works to produce a work based on these
+ * files, these files do not by themselves cause the resulting work to be
+ * covered by the GNU General Public License. However the source code for
+ * these files must still be made available in accordance with section (3)
+ * of the GNU General Public License.
+ *
+ * This exception does not invalidate any other reasons why a work based on
+ * this file might be covered by the GNU General Public License.
+ */
+
+#ifndef __JASTEGAL_H
+#define __JASTEGAL_H
+
+#ifndef __cplusplus
+#error "You need a C++ compiler to compile Jastegal"
+#endif
+
+#include <string>
+#include <vector>
+
+#define JASTEGAL_VERSION "0.1b"
+
+typedef unsigned char u8;
+typedef enum { undef, encode, decode } action;
+
+typedef struct {
+ u8 r;
+ u8 g;
+ u8 b;
+} rgb;
+
+int steganoEncode (std::string inImg, std::string outImg, std::string fname = "");
+
+std::string steganoDecode (std::string inImg);
+
+std::vector<u8> bitsplit (u8 data);
+
+unsigned int fileSize (std::string fname);
+
+std::string fileContent (std::string fname);
+
+void printHelp (std::string arg);
+
+char* zCompress (char* uncompressed, unsigned int uLen, unsigned int &cLen);
+
+char* zUncompress (char* compressed, unsigned int cLen, unsigned int &uLen);
+
+#endif
+
diff --git a/utils.cpp b/utils.cpp
new file mode 100644
index 0000000..24a8761
--- /dev/null
+++ b/utils.cpp
@@ -0,0 +1,111 @@
+/*
+ * utils.cpp
+ *
+ * The files in this directory and elsewhere which refer to this LICENCE
+ * file are part of Jastegal (Just Another Steganography algorithm)
+ *
+ * Copyright (C) 2009 BlackLight
+ *
+ * Jastegal is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 3 or (at your option) any later
+ * version.
+ *
+ * Jastegal is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with Jastegal; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * As a special exception, if other files instantiate templates or use
+ * macros or inline functions from these files, or you compile these
+ * files and link them with other works to produce a work based on these
+ * files, these files do not by themselves cause the resulting work to be
+ * covered by the GNU General Public License. However the source code for
+ * these files must still be made available in accordance with section (3)
+ * of the GNU General Public License.
+ *
+ * This exception does not invalidate any other reasons why a work based on
+ * this file might be covered by the GNU General Public License.
+ */
+
+#include <iostream>
+#include <fstream>
+
+#include "jastegal.h"
+using namespace std;
+
+vector<u8> bitsplit (u8 data) {
+ unsigned int size = sizeof(data)*8;
+ u8* bits = new u8[size+1];
+
+ for (int i=size-1; i>=0; i--)
+ bits[size-i-1] = (data & (1 << i)) >> i;
+
+ vector<u8> v;
+ v.assign(bits, bits+size);
+ delete [] bits;
+ return v;
+}
+
+unsigned int fileSize (string fname) {
+ ifstream in(fname.c_str());
+
+ if (!in)
+ return -1;
+
+ in.seekg(0, ios::end);
+ unsigned int size = in.tellg();
+ in.close();
+ return size;
+}
+
+string fileContent (string fname) {
+ if (!fname.empty()) {
+ char *buf = NULL;
+ ifstream in(fname.c_str());
+
+ if (!in)
+ return string("");
+
+ unsigned int size = fileSize(fname);
+ buf = new char[size];
+
+ if (!buf)
+ return string("");
+
+ in.read(buf,size);
+ in.close();
+ return string(buf);
+ } else {
+ string content, line;
+
+ while (getline(cin,line))
+ content.append(line);
+
+ return content;
+ }
+}
+
+void printHelp (string arg) {
+ cerr << "Jastegal (Just Another Steganography Algorithm) v." << JASTEGAL_VERSION << endl
+ << "c0ded by BlackLight <blacklight@autistici.org>" << endl << endl
+ << "Usage: " << arg << " [-d|-e] <-i image file> [-o output image file] [-f file to be steganographied]" << endl << endl
+ << "-d:\t\tPerform a decoding from an image" << endl
+ << "-e:\t\tPerform an encoding to an image" << endl
+ << "-i:\t\tSpecify the input image to be processed. In case of decoding, the content of this file will be de-steganographied," << endl
+ << "\t\twhile in case of encoding this is the image to steganography from" << endl
+ << "-o:\t\tSpecify the output image. This parameter is mandatory in encoding phase, as it specifies the file name containing" << endl
+ << "\t\tthe image with the steganographied data" << endl
+ << "-f:\t\tSpecify, in encoding phase, the file containing data to be steganographied. If this option is not specified, the" << endl
+ << "\t\tdata will be gathered via stdin" << endl << endl
+ << "Examples:" << endl
+ << "\tjastegal -e -i input_image.png -o output_image.png -f file.txt" << endl
+ << "\tThis will encode the data in file.txt using input_image.png as image, and putting the output in output_image.png" << endl << endl
+ << "\tjastegal -d -i input_image.png" << endl
+ << "\tThis will decode the data in input_image.png to stdout" << endl;
+}
+