320 lines
11 KiB
Python
320 lines
11 KiB
Python
#! /usr/bin/python
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# ignobleepub.pyw, version 3
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# To run this program install Python 2.6 from <http://www.python.org/download/>
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# and OpenSSL or PyCrypto from http://www.voidspace.org.uk/python/modules.shtml#pycrypto
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# (make sure to install the version for Python 2.6). Save this script file as
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# ignobleepub.pyw and double-click on it to run it.
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# Revision history:
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# 1 - Initial release
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# 2 - Added OS X support by using OpenSSL when available
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# 3 - screen out improper key lengths to prevent segfaults on Linux
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from __future__ import with_statement
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__license__ = 'GPL v3'
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import sys
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import os
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import zlib
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import zipfile
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from zipfile import ZipFile, ZIP_STORED, ZIP_DEFLATED
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from contextlib import closing
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import xml.etree.ElementTree as etree
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import Tkinter
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import Tkconstants
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import tkFileDialog
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import tkMessageBox
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class IGNOBLEError(Exception):
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pass
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def _load_crypto_libcrypto():
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from ctypes import CDLL, POINTER, c_void_p, c_char_p, c_int, c_long, \
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Structure, c_ulong, create_string_buffer, cast
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from ctypes.util import find_library
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libcrypto = find_library('crypto')
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if libcrypto is None:
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raise IGNOBLEError('libcrypto not found')
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libcrypto = CDLL(libcrypto)
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AES_MAXNR = 14
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c_char_pp = POINTER(c_char_p)
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c_int_p = POINTER(c_int)
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class AES_KEY(Structure):
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_fields_ = [('rd_key', c_long * (4 * (AES_MAXNR + 1))),
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('rounds', c_int)]
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AES_KEY_p = POINTER(AES_KEY)
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def F(restype, name, argtypes):
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func = getattr(libcrypto, name)
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func.restype = restype
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func.argtypes = argtypes
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return func
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AES_cbc_encrypt = F(None, 'AES_cbc_encrypt',
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[c_char_p, c_char_p, c_ulong, AES_KEY_p, c_char_p,
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c_int])
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AES_set_decrypt_key = F(c_int, 'AES_set_decrypt_key',
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[c_char_p, c_int, AES_KEY_p])
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AES_cbc_encrypt = F(None, 'AES_cbc_encrypt',
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[c_char_p, c_char_p, c_ulong, AES_KEY_p, c_char_p,
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c_int])
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class AES(object):
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def __init__(self, userkey):
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self._blocksize = len(userkey)
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if (self._blocksize != 16) and (self._blocksize != 24) and (self._blocksize != 32) :
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raise IGNOBLEError('AES improper key used')
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return
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key = self._key = AES_KEY()
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rv = AES_set_decrypt_key(userkey, len(userkey) * 8, key)
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if rv < 0:
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raise IGNOBLEError('Failed to initialize AES key')
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def decrypt(self, data):
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out = create_string_buffer(len(data))
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iv = ("\x00" * self._blocksize)
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rv = AES_cbc_encrypt(data, out, len(data), self._key, iv, 0)
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if rv == 0:
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raise IGNOBLEError('AES decryption failed')
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return out.raw
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return AES
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def _load_crypto_pycrypto():
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from Crypto.Cipher import AES as _AES
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class AES(object):
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def __init__(self, key):
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self._aes = _AES.new(key, _AES.MODE_CBC)
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def decrypt(self, data):
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return self._aes.decrypt(data)
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return AES
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def _load_crypto():
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AES = None
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for loader in (_load_crypto_libcrypto, _load_crypto_pycrypto):
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try:
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AES = loader()
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break
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except (ImportError, IGNOBLEError):
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pass
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return AES
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AES = _load_crypto()
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"""
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Decrypt Barnes & Noble ADEPT encrypted EPUB books.
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"""
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META_NAMES = ('mimetype', 'META-INF/rights.xml', 'META-INF/encryption.xml')
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NSMAP = {'adept': 'http://ns.adobe.com/adept',
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'enc': 'http://www.w3.org/2001/04/xmlenc#'}
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class ZipInfo(zipfile.ZipInfo):
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def __init__(self, *args, **kwargs):
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if 'compress_type' in kwargs:
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compress_type = kwargs.pop('compress_type')
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super(ZipInfo, self).__init__(*args, **kwargs)
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self.compress_type = compress_type
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class Decryptor(object):
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def __init__(self, bookkey, encryption):
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enc = lambda tag: '{%s}%s' % (NSMAP['enc'], tag)
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# self._aes = AES.new(bookkey, AES.MODE_CBC)
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self._aes = AES(bookkey)
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encryption = etree.fromstring(encryption)
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self._encrypted = encrypted = set()
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expr = './%s/%s/%s' % (enc('EncryptedData'), enc('CipherData'),
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enc('CipherReference'))
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for elem in encryption.findall(expr):
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path = elem.get('URI', None)
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if path is not None:
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encrypted.add(path)
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def decompress(self, bytes):
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dc = zlib.decompressobj(-15)
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bytes = dc.decompress(bytes)
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ex = dc.decompress('Z') + dc.flush()
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if ex:
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bytes = bytes + ex
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return bytes
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def decrypt(self, path, data):
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if path in self._encrypted:
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data = self._aes.decrypt(data)[16:]
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data = data[:-ord(data[-1])]
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data = self.decompress(data)
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return data
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def cli_main(argv=sys.argv):
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progname = os.path.basename(argv[0])
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if AES is None:
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print "%s: This script requires OpenSSL or PyCrypto, which must be installed " \
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"separately. Read the top-of-script comment for details." % \
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(progname,)
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return 1
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if len(argv) != 4:
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print "usage: %s KEYFILE INBOOK OUTBOOK" % (progname,)
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return 1
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keypath, inpath, outpath = argv[1:]
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with open(keypath, 'rb') as f:
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keyb64 = f.read()
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key = keyb64.decode('base64')[:16]
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# aes = AES.new(key, AES.MODE_CBC)
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aes = AES(key)
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with closing(ZipFile(open(inpath, 'rb'))) as inf:
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namelist = set(inf.namelist())
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if 'META-INF/rights.xml' not in namelist or \
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'META-INF/encryption.xml' not in namelist:
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raise IGNOBLEError('%s: not an B&N ADEPT EPUB' % (inpath,))
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for name in META_NAMES:
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namelist.remove(name)
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rights = etree.fromstring(inf.read('META-INF/rights.xml'))
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adept = lambda tag: '{%s}%s' % (NSMAP['adept'], tag)
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expr = './/%s' % (adept('encryptedKey'),)
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bookkey = ''.join(rights.findtext(expr))
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bookkey = aes.decrypt(bookkey.decode('base64'))
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bookkey = bookkey[:-ord(bookkey[-1])]
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encryption = inf.read('META-INF/encryption.xml')
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decryptor = Decryptor(bookkey[-16:], encryption)
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kwds = dict(compression=ZIP_DEFLATED, allowZip64=False)
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with closing(ZipFile(open(outpath, 'wb'), 'w', **kwds)) as outf:
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zi = ZipInfo('mimetype', compress_type=ZIP_STORED)
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outf.writestr(zi, inf.read('mimetype'))
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for path in namelist:
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data = inf.read(path)
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outf.writestr(path, decryptor.decrypt(path, data))
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return 0
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class DecryptionDialog(Tkinter.Frame):
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def __init__(self, root):
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Tkinter.Frame.__init__(self, root, border=5)
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self.status = Tkinter.Label(self, text='Select files for decryption')
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self.status.pack(fill=Tkconstants.X, expand=1)
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body = Tkinter.Frame(self)
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body.pack(fill=Tkconstants.X, expand=1)
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sticky = Tkconstants.E + Tkconstants.W
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body.grid_columnconfigure(1, weight=2)
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Tkinter.Label(body, text='Key file').grid(row=0)
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self.keypath = Tkinter.Entry(body, width=30)
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self.keypath.grid(row=0, column=1, sticky=sticky)
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if os.path.exists('bnepubkey.b64'):
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self.keypath.insert(0, 'bnepubkey.b64')
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button = Tkinter.Button(body, text="...", command=self.get_keypath)
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button.grid(row=0, column=2)
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Tkinter.Label(body, text='Input file').grid(row=1)
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self.inpath = Tkinter.Entry(body, width=30)
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self.inpath.grid(row=1, column=1, sticky=sticky)
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button = Tkinter.Button(body, text="...", command=self.get_inpath)
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button.grid(row=1, column=2)
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Tkinter.Label(body, text='Output file').grid(row=2)
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self.outpath = Tkinter.Entry(body, width=30)
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self.outpath.grid(row=2, column=1, sticky=sticky)
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button = Tkinter.Button(body, text="...", command=self.get_outpath)
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button.grid(row=2, column=2)
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buttons = Tkinter.Frame(self)
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buttons.pack()
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botton = Tkinter.Button(
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buttons, text="Decrypt", width=10, command=self.decrypt)
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botton.pack(side=Tkconstants.LEFT)
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Tkinter.Frame(buttons, width=10).pack(side=Tkconstants.LEFT)
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button = Tkinter.Button(
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buttons, text="Quit", width=10, command=self.quit)
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button.pack(side=Tkconstants.RIGHT)
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def get_keypath(self):
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keypath = tkFileDialog.askopenfilename(
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parent=None, title='Select B&N EPUB key file',
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defaultextension='.b64',
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filetypes=[('base64-encoded files', '.b64'),
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('All Files', '.*')])
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if keypath:
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keypath = os.path.normpath(keypath)
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self.keypath.delete(0, Tkconstants.END)
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self.keypath.insert(0, keypath)
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return
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def get_inpath(self):
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inpath = tkFileDialog.askopenfilename(
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parent=None, title='Select B&N-encrypted EPUB file to decrypt',
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defaultextension='.epub', filetypes=[('EPUB files', '.epub'),
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('All files', '.*')])
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if inpath:
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inpath = os.path.normpath(inpath)
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self.inpath.delete(0, Tkconstants.END)
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self.inpath.insert(0, inpath)
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return
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def get_outpath(self):
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outpath = tkFileDialog.asksaveasfilename(
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parent=None, title='Select unencrypted EPUB file to produce',
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defaultextension='.epub', filetypes=[('EPUB files', '.epub'),
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('All files', '.*')])
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if outpath:
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outpath = os.path.normpath(outpath)
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self.outpath.delete(0, Tkconstants.END)
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self.outpath.insert(0, outpath)
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return
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def decrypt(self):
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keypath = self.keypath.get()
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inpath = self.inpath.get()
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outpath = self.outpath.get()
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if not keypath or not os.path.exists(keypath):
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self.status['text'] = 'Specified key file does not exist'
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return
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if not inpath or not os.path.exists(inpath):
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self.status['text'] = 'Specified input file does not exist'
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return
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if not outpath:
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self.status['text'] = 'Output file not specified'
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return
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if inpath == outpath:
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self.status['text'] = 'Must have different input and output files'
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return
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argv = [sys.argv[0], keypath, inpath, outpath]
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self.status['text'] = 'Decrypting...'
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try:
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cli_main(argv)
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except Exception, e:
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self.status['text'] = 'Error: ' + str(e)
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return
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self.status['text'] = 'File successfully decrypted'
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def gui_main():
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root = Tkinter.Tk()
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if AES is None:
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root.withdraw()
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tkMessageBox.showerror(
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"Ignoble EPUB Decrypter",
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"This script requires OpenSSL or PyCrypto, which must be installed "
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"separately. Read the top-of-script comment for details.")
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return 1
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root.title('Ignoble EPUB Decrypter')
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root.resizable(True, False)
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root.minsize(300, 0)
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DecryptionDialog(root).pack(fill=Tkconstants.X, expand=1)
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root.mainloop()
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return 0
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if __name__ == '__main__':
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if len(sys.argv) > 1:
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sys.exit(cli_main())
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sys.exit(gui_main())
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