Stegano/stegano/lsb/lsb.py
2017-01-19 07:22:51 +01:00

133 lines
4.1 KiB
Python
Executable file

#!/usr/bin/env python
#-*- coding: utf-8 -*-
# Stéganô - Stéganô is a basic Python Steganography module.
# Copyright (C) 2010-2017 Cédric Bonhomme - https://www.cedricbonhomme.org
#
# For more information : https://github.com/cedricbonhomme/Stegano
#
# This program 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 of the License, or
# (at your option) any later version.
#
# This program 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 this program. If not, see <http://www.gnu.org/licenses/>
__author__ = "Cedric Bonhomme"
__version__ = "$Revision: 0.2.2 $"
__date__ = "$Date: 2016/08/04 $"
__license__ = "GPLv3"
import sys
from PIL import Image
from stegano import tools
try:
input = raw_input
except NameError:
pass
def hide(input_image_file, message, auto_convert_rgb=False):
"""
Hide a message (string) in an image with the
LSB (Least Significant Bit) technique.
"""
message_length = len(message)
assert message_length != 0, "message length is zero"
img = Image.open(input_image_file)
if img.mode != 'RGB':
if not auto_convert_rgb:
print('The mode of the image is not RGB. Mode is {}'.\
format(img.mode))
answer = input('Convert the image to RGB ? [Y / n]\n') or 'Y'
if answer.lower() == 'n':
raise Exception('Not a RGB image.')
img = img.convert('RGB')
encoded = img.copy()
width, height = img.size
index = 0
message = str(message_length) + ":" + str(message)
message_bits = "".join(tools.a2bits_list(message))
message_bits += '0' * ((3 - (len(message_bits) % 3)) % 3)
npixels = width * height
len_message_bits = len(message_bits)
if len_message_bits > npixels * 3:
raise Exception("The message you want to hide is too long: {}". \
format(message_length))
for row in range(height):
for col in range(width):
if index + 3 <= len_message_bits :
# Get the colour component.
(r, g, b) = img.getpixel((col, row))
# Change the Least Significant Bit of each colour component.
r = tools.setlsb(r, message_bits[index])
g = tools.setlsb(g, message_bits[index+1])
b = tools.setlsb(b, message_bits[index+2])
# Save the new pixel
encoded.putpixel((col, row), (r, g , b))
index += 3
else:
img.close()
return encoded
img.close()
return encoded
def reveal(input_image_file):
"""
Find a message in an image
(with the LSB technique).
"""
img = Image.open(input_image_file)
width, height = img.size
buff, count = 0, 0
bitab = []
limit = None
for row in range(height):
for col in range(width):
# color = [r, g, b]
for color in img.getpixel((col, row)):
buff += (color&1)<<(7-count)
count += 1
if count == 8:
bitab.append(chr(buff))
buff, count = 0, 0
if bitab[-1] == ":" and limit == None:
try:
limit = int("".join(bitab[:-1]))
except:
pass
if len(bitab)-len(str(limit))-1 == limit :
img.close()
return "".join(bitab)[len(str(limit))+1:]
img.close()
return ""
def write(image, output_image_file):
"""
"""
try:
image.save(output_image_file)
except Exception as e:
# If hide() returns an error (Too long message).
print(e)
finally:
image.close()