Python script to encrypt and append a zipfile to an image file.

steganography_v1.py

'''Hide a zipfile in an image or unpack an image with a hidden archive in it'''
 
import argparse
from zipfile import ZipFile
 
 
def hide(image_file, archive_file):
'''Append an archive onto the end of an image'''
 
# open the image file in "append binary" mode
with open(image_file, "ab") as image:
# open the archive file in "read only binary" mode
with open(archive_file, "rb") as archive:
# Append a newline and the contents of the archive onto the image
image.write("\n" + archive.read())
 
 
def unhide(unhide_file):
'''Unpack a zipfile'''
zip = ZipFile(unhide_file)
zip.extractall()
 
 
if __name__ == '__main__':
parser = argparse.ArgumentParser()
parser.add_argument('-H', '--hide', nargs=2)
parser.add_argument('-U', '--unhide')
args = parser.parse_args()
if args.hide:
hide(*args.hide)
if args.unhide:
unhide(args.unhide)

steganography_v3.py

'''Encrypt and hide a zipfile in an image or unpack an image with a hidden archive in it'''

import argparse
from zipfile import ZipFile
import base64
import StringIO
import sys
from getpass import getpass
from bcrypt import gensalt, hashpw
from nacl.secret import SecretBox
import nacl.utils


def key_32(salt):
    '''Returns 32 byte key'''
    return hashpw(getpass(), salt)[-32:]


def hide(image_file, archive_file):
    '''Append an encrypted archive onto the end of an image'''

    salt = gensalt()
    box = SecretBox(key_32(salt))
    nonce = "dg1" + nacl.utils.random(21)

    # open the image file in "append binary" mode
    with open(image_file, "ab") as image:
        # open the archive file in "read only binary" mode
        with open(archive_file, "rb") as a:
            archive = a.read()
            # Append a newline and the encrypted contents of the archive onto the image
            image.write("EOF" + box.encrypt(archive, nonce) + "EOF" + salt)


def unhide(unhide_file):
    '''Unpack a zipfile'''

    with open(unhide_file, "rb") as f:
        hidden_file = f.read()
        image, encrypted, salt = hidden_file.split("EOF")
        box = SecretBox(key_32(salt))
        # zipfile needs a file-like object
        e_string = StringIO.StringIO()
        # decrypt the file
        e_string.write(box.decrypt(encrypted))
        archive = ZipFile(e_string)
        archive.extractall()
        sys.stdout.write("File sucessfully extracted\n")


if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('-H', '--hide', nargs=2)
    parser.add_argument('-U', '--unhide')
    args = parser.parse_args()
    if args.hide:
        hide(*args.hide)
    if args.unhide:
        unhide(args.unhide)

steganograpy_v2.py

'''Encrypt and hide a zipfile in an image or unpack an image with a hidden archive in it'''

import argparse
from zipfile import ZipFile
import nacl.secret
import nacl.utils
import base64
import StringIO
import getpass


def key_32():
    '''Returns 32 byte key'''

    BLOCK_SIZE = 32
    PADDING = "0"

    # pad string to 32 byes
    pad = lambda s: s + (BLOCK_SIZE - len(s) % BLOCK_SIZE) * PADDING
    return pad(base64.b64encode(getpass.getpass("Password? ")))


def hide(image_file, archive_file):
    '''Append an encrypted archive onto the end of an image'''

    box = nacl.secret.SecretBox(key_32())
    nonce = "dg1" + nacl.utils.random(21)

    # open the image file in "append binary" mode
    with open(image_file, "ab") as image:
        # open the archive file in "read only binary" mode
        with open(archive_file, "rb") as a:
            archive = a.read()
            # Append a newline and the encrypted contents of the archive onto the image
            image.write("EOF" + box.encrypt(archive, nonce))


def unhide(unhide_file):
    '''Unpack a zipfile'''

    with open(unhide_file, "rb") as f:
        hidden_file = f.read()
        encrypted = hidden_file.split('EOF')
        box = nacl.secret.SecretBox(key_32())
        # zipfile needs a file-like object
        e_string = StringIO.StringIO()
        e_string.write(box.decrypt(encrypted[1]))
        zip = ZipFile(e_string)
        zip.extractall()
        print "files extracted"


if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('-H', '--hide', nargs=2)
    parser.add_argument('-U', '--unhide')
    args = parser.parse_args()
    if args.hide:
        hide(*args.hide)
    if args.unhide:
        unhide(args.unhide)