443 lines
17 KiB
Python
443 lines
17 KiB
Python
#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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# ignobleepub.py
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# Copyright © 2009-2020 by i♥cabbages, Apprentice Harper et al.
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# Released under the terms of the GNU General Public Licence, version 3
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# <http://www.gnu.org/licenses/>
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#
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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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# 3.1 - Allow Windows versions of libcrypto to be found
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# 3.2 - add support for encoding to 'utf-8' when building up list of files to decrypt from encryption.xml
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# 3.3 - On Windows try PyCrypto first, OpenSSL next
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# 3.4 - Modify interface to allow use with import
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# 3.5 - Fix for potential problem with PyCrypto
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# 3.6 - Revised to allow use in calibre plugins to eliminate need for duplicate code
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# 3.7 - Tweaked to match ineptepub more closely
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# 3.8 - Fixed to retain zip file metadata (e.g. file modification date)
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# 3.9 - moved unicode_argv call inside main for Windows DeDRM compatibility
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# 4.0 - Work if TkInter is missing
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# 4.1 - Import tkFileDialog, don't assume something else will import it.
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# 5.0 - Python 3 for calibre 5.0
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"""
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Decrypt Barnes & Noble encrypted ePub books.
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"""
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__license__ = 'GPL v3'
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__version__ = "5.0"
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import sys
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import os
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import traceback
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import zlib
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import zipfile
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from zipfile import ZipInfo, 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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# Wrap a stream so that output gets flushed immediately
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# and also make sure that any unicode strings get
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# encoded using "replace" before writing them.
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class SafeUnbuffered:
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def __init__(self, stream):
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self.stream = stream
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self.encoding = stream.encoding
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if self.encoding == None:
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self.encoding = "utf-8"
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def write(self, data):
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if isinstance(data,str):
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data = data.encode(self.encoding,"replace")
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self.stream.buffer.write(data)
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self.stream.buffer.flush()
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def __getattr__(self, attr):
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return getattr(self.stream, attr)
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try:
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from calibre.constants import iswindows, isosx
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except:
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iswindows = sys.platform.startswith('win')
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isosx = sys.platform.startswith('darwin')
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def unicode_argv():
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if iswindows:
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# Uses shell32.GetCommandLineArgvW to get sys.argv as a list of Unicode
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# strings.
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# Versions 2.x of Python don't support Unicode in sys.argv on
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# Windows, with the underlying Windows API instead replacing multi-byte
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# characters with '?'.
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from ctypes import POINTER, byref, cdll, c_int, windll
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from ctypes.wintypes import LPCWSTR, LPWSTR
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GetCommandLineW = cdll.kernel32.GetCommandLineW
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GetCommandLineW.argtypes = []
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GetCommandLineW.restype = LPCWSTR
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CommandLineToArgvW = windll.shell32.CommandLineToArgvW
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CommandLineToArgvW.argtypes = [LPCWSTR, POINTER(c_int)]
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CommandLineToArgvW.restype = POINTER(LPWSTR)
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cmd = GetCommandLineW()
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argc = c_int(0)
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argv = CommandLineToArgvW(cmd, byref(argc))
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if argc.value > 0:
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# Remove Python executable and commands if present
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start = argc.value - len(sys.argv)
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return [argv[i] for i in
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range(start, argc.value)]
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return ["ineptepub.py"]
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else:
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argvencoding = sys.stdin.encoding
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if argvencoding == None:
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argvencoding = "utf-8"
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return argv
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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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if iswindows:
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libcrypto = find_library('libeay32')
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else:
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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_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, '\x00'*16)
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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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cryptolist = (_load_crypto_libcrypto, _load_crypto_pycrypto)
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if sys.platform.startswith('win'):
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cryptolist = (_load_crypto_pycrypto, _load_crypto_libcrypto)
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for loader in cryptolist:
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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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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 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(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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path = path.encode('utf-8')
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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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# check file to make check whether it's probably an Adobe Adept encrypted ePub
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def ignobleBook(inpath):
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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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return False
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try:
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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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if len(bookkey) == 64:
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return True
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except:
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# if we couldn't check, assume it is
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return True
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return False
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def decryptBook(keyb64, inpath, outpath):
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if AES is None:
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raise IGNOBLEError("PyCrypto or OpenSSL must be installed.")
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key = keyb64.decode('base64')[:16]
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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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print("{0:s} is DRM-free.".format(os.path.basename(inpath)))
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return 1
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for name in META_NAMES:
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namelist.remove(name)
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try:
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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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if len(bookkey) != 64:
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print("{0:s} is not a secure Barnes & Noble ePub.".format(os.path.basename(inpath)))
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return 1
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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')
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zi.compress_type=ZIP_STORED
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try:
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# if the mimetype is present, get its info, including time-stamp
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oldzi = inf.getinfo('mimetype')
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# copy across fields to be preserved
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zi.date_time = oldzi.date_time
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zi.comment = oldzi.comment
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zi.extra = oldzi.extra
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zi.internal_attr = oldzi.internal_attr
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# external attributes are dependent on the create system, so copy both.
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zi.external_attr = oldzi.external_attr
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zi.create_system = oldzi.create_system
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except:
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pass
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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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zi = ZipInfo(path)
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zi.compress_type=ZIP_DEFLATED
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try:
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# get the file info, including time-stamp
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oldzi = inf.getinfo(path)
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# copy across useful fields
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zi.date_time = oldzi.date_time
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zi.comment = oldzi.comment
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zi.extra = oldzi.extra
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zi.internal_attr = oldzi.internal_attr
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# external attributes are dependent on the create system, so copy both.
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zi.external_attr = oldzi.external_attr
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zi.create_system = oldzi.create_system
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except:
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pass
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outf.writestr(zi, decryptor.decrypt(path, data))
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except:
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print("Could not decrypt {0:s} because of an exception:\n{1:s}".format(os.path.basename(inpath), traceback.format_exc()))
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return 2
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return 0
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def cli_main():
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sys.stdout=SafeUnbuffered(sys.stdout)
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sys.stderr=SafeUnbuffered(sys.stderr)
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argv=unicode_argv()
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progname = os.path.basename(argv[0])
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if len(argv) != 4:
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print("usage: {0} <keyfile.b64> <inbook.epub> <outbook.epub>".format(progname))
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return 1
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keypath, inpath, outpath = argv[1:]
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userkey = open(keypath,'rb').read()
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result = decryptBook(userkey, inpath, outpath)
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if result == 0:
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print("Successfully decrypted {0:s} as {1:s}".format(os.path.basename(inpath),os.path.basename(outpath)))
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return result
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def gui_main():
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try:
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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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import traceback
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except:
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return cli_main()
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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 Barnes & Noble \'.b64\' 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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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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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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userkey = open(keypath,'rb').read()
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self.status['text'] = "Decrypting..."
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try:
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decrypt_status = decryptBook(userkey, inpath, outpath)
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except Exception as e:
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self.status['text'] = "Error: {0}".format(e.args[0])
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return
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if decrypt_status == 0:
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self.status['text'] = "File successfully decrypted"
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else:
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self.status['text'] = "The was an error decrypting the file."
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root = Tkinter.Tk()
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root.title("Barnes & Noble ePub Decrypter v.{0}".format(__version__))
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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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