#! /usr/bin/python from __future__ import with_statement # ignobleepub.pyw, version 3.4 # To run this program install Python 2.6 from # and OpenSSL or PyCrypto from http://www.voidspace.org.uk/python/modules.shtml#pycrypto # (make sure to install the version for Python 2.6). Save this script file as # ignobleepub.pyw and double-click on it to run it. # Revision history: # 1 - Initial release # 2 - Added OS X support by using OpenSSL when available # 3 - screen out improper key lengths to prevent segfaults on Linux # 3.1 - Allow Windows versions of libcrypto to be found # 3.2 - add support for encoding to 'utf-8' when building up list of files to cecrypt from encryption.xml # 3.3 - On Windows try PyCrypto first and OpenSSL next # 3.4 - Modify interace to allow use with import __license__ = 'GPL v3' import sys import os import zlib import zipfile from zipfile import ZipFile, ZIP_STORED, ZIP_DEFLATED from contextlib import closing import xml.etree.ElementTree as etree import Tkinter import Tkconstants import tkFileDialog import tkMessageBox class IGNOBLEError(Exception): pass def _load_crypto_libcrypto(): from ctypes import CDLL, POINTER, c_void_p, c_char_p, c_int, c_long, \ Structure, c_ulong, create_string_buffer, cast from ctypes.util import find_library if sys.platform.startswith('win'): libcrypto = find_library('libeay32') else: libcrypto = find_library('crypto') if libcrypto is None: raise IGNOBLEError('libcrypto not found') libcrypto = CDLL(libcrypto) AES_MAXNR = 14 c_char_pp = POINTER(c_char_p) c_int_p = POINTER(c_int) class AES_KEY(Structure): _fields_ = [('rd_key', c_long * (4 * (AES_MAXNR + 1))), ('rounds', c_int)] AES_KEY_p = POINTER(AES_KEY) def F(restype, name, argtypes): func = getattr(libcrypto, name) func.restype = restype func.argtypes = argtypes return func AES_cbc_encrypt = F(None, 'AES_cbc_encrypt', [c_char_p, c_char_p, c_ulong, AES_KEY_p, c_char_p, c_int]) AES_set_decrypt_key = F(c_int, 'AES_set_decrypt_key', [c_char_p, c_int, AES_KEY_p]) AES_cbc_encrypt = F(None, 'AES_cbc_encrypt', [c_char_p, c_char_p, c_ulong, AES_KEY_p, c_char_p, c_int]) class AES(object): def __init__(self, userkey): self._blocksize = len(userkey) if (self._blocksize != 16) and (self._blocksize != 24) and (self._blocksize != 32) : raise IGNOBLEError('AES improper key used') return key = self._key = AES_KEY() rv = AES_set_decrypt_key(userkey, len(userkey) * 8, key) if rv < 0: raise IGNOBLEError('Failed to initialize AES key') def decrypt(self, data): out = create_string_buffer(len(data)) iv = ("\x00" * self._blocksize) rv = AES_cbc_encrypt(data, out, len(data), self._key, iv, 0) if rv == 0: raise IGNOBLEError('AES decryption failed') return out.raw return AES def _load_crypto_pycrypto(): from Crypto.Cipher import AES as _AES class AES(object): def __init__(self, key): self._aes = _AES.new(key, _AES.MODE_CBC) def decrypt(self, data): return self._aes.decrypt(data) return AES def _load_crypto(): AES = None cryptolist = (_load_crypto_libcrypto, _load_crypto_pycrypto) if sys.platform.startswith('win'): cryptolist = (_load_crypto_pycrypto, _load_crypto_libcrypto) for loader in cryptolist: try: AES = loader() break except (ImportError, IGNOBLEError): pass return AES AES = _load_crypto() """ Decrypt Barnes & Noble ADEPT encrypted EPUB books. """ META_NAMES = ('mimetype', 'META-INF/rights.xml', 'META-INF/encryption.xml') NSMAP = {'adept': 'http://ns.adobe.com/adept', 'enc': 'http://www.w3.org/2001/04/xmlenc#'} class ZipInfo(zipfile.ZipInfo): def __init__(self, *args, **kwargs): if 'compress_type' in kwargs: compress_type = kwargs.pop('compress_type') super(ZipInfo, self).__init__(*args, **kwargs) self.compress_type = compress_type class Decryptor(object): def __init__(self, bookkey, encryption): enc = lambda tag: '{%s}%s' % (NSMAP['enc'], tag) # self._aes = AES.new(bookkey, AES.MODE_CBC) self._aes = AES(bookkey) encryption = etree.fromstring(encryption) self._encrypted = encrypted = set() expr = './%s/%s/%s' % (enc('EncryptedData'), enc('CipherData'), enc('CipherReference')) for elem in encryption.findall(expr): path = elem.get('URI', None) path = path.encode('utf-8') if path is not None: encrypted.add(path) def decompress(self, bytes): dc = zlib.decompressobj(-15) bytes = dc.decompress(bytes) ex = dc.decompress('Z') + dc.flush() if ex: bytes = bytes + ex return bytes def decrypt(self, path, data): if path in self._encrypted: data = self._aes.decrypt(data)[16:] data = data[:-ord(data[-1])] data = self.decompress(data) return data class DecryptionDialog(Tkinter.Frame): def __init__(self, root): Tkinter.Frame.__init__(self, root, border=5) self.status = Tkinter.Label(self, text='Select files for decryption') self.status.pack(fill=Tkconstants.X, expand=1) body = Tkinter.Frame(self) body.pack(fill=Tkconstants.X, expand=1) sticky = Tkconstants.E + Tkconstants.W body.grid_columnconfigure(1, weight=2) Tkinter.Label(body, text='Key file').grid(row=0) self.keypath = Tkinter.Entry(body, width=30) self.keypath.grid(row=0, column=1, sticky=sticky) if os.path.exists('bnepubkey.b64'): self.keypath.insert(0, 'bnepubkey.b64') button = Tkinter.Button(body, text="...", command=self.get_keypath) button.grid(row=0, column=2) Tkinter.Label(body, text='Input file').grid(row=1) self.inpath = Tkinter.Entry(body, width=30) self.inpath.grid(row=1, column=1, sticky=sticky) button = Tkinter.Button(body, text="...", command=self.get_inpath) button.grid(row=1, column=2) Tkinter.Label(body, text='Output file').grid(row=2) self.outpath = Tkinter.Entry(body, width=30) self.outpath.grid(row=2, column=1, sticky=sticky) button = Tkinter.Button(body, text="...", command=self.get_outpath) button.grid(row=2, column=2) buttons = Tkinter.Frame(self) buttons.pack() botton = Tkinter.Button( buttons, text="Decrypt", width=10, command=self.decrypt) botton.pack(side=Tkconstants.LEFT) Tkinter.Frame(buttons, width=10).pack(side=Tkconstants.LEFT) button = Tkinter.Button( buttons, text="Quit", width=10, command=self.quit) button.pack(side=Tkconstants.RIGHT) def get_keypath(self): keypath = tkFileDialog.askopenfilename( parent=None, title='Select B&N EPUB key file', defaultextension='.b64', filetypes=[('base64-encoded files', '.b64'), ('All Files', '.*')]) if keypath: keypath = os.path.normpath(keypath) self.keypath.delete(0, Tkconstants.END) self.keypath.insert(0, keypath) return def get_inpath(self): inpath = tkFileDialog.askopenfilename( parent=None, title='Select B&N-encrypted EPUB file to decrypt', defaultextension='.epub', filetypes=[('EPUB files', '.epub'), ('All files', '.*')]) if inpath: inpath = os.path.normpath(inpath) self.inpath.delete(0, Tkconstants.END) self.inpath.insert(0, inpath) return def get_outpath(self): outpath = tkFileDialog.asksaveasfilename( parent=None, title='Select unencrypted EPUB file to produce', defaultextension='.epub', filetypes=[('EPUB files', '.epub'), ('All files', '.*')]) if outpath: outpath = os.path.normpath(outpath) self.outpath.delete(0, Tkconstants.END) self.outpath.insert(0, outpath) return def decrypt(self): keypath = self.keypath.get() inpath = self.inpath.get() outpath = self.outpath.get() if not keypath or not os.path.exists(keypath): self.status['text'] = 'Specified key file does not exist' return if not inpath or not os.path.exists(inpath): self.status['text'] = 'Specified input file does not exist' return if not outpath: self.status['text'] = 'Output file not specified' return if inpath == outpath: self.status['text'] = 'Must have different input and output files' return argv = [sys.argv[0], keypath, inpath, outpath] self.status['text'] = 'Decrypting...' try: cli_main(argv) except Exception, e: self.status['text'] = 'Error: ' + str(e) return self.status['text'] = 'File successfully decrypted' def decryptBook(keypath, inpath, outpath): with open(keypath, 'rb') as f: keyb64 = f.read() key = keyb64.decode('base64')[:16] # aes = AES.new(key, AES.MODE_CBC) aes = AES(key) with closing(ZipFile(open(inpath, 'rb'))) as inf: namelist = set(inf.namelist()) if 'META-INF/rights.xml' not in namelist or \ 'META-INF/encryption.xml' not in namelist: raise IGNOBLEError('%s: not an B&N ADEPT EPUB' % (inpath,)) for name in META_NAMES: namelist.remove(name) rights = etree.fromstring(inf.read('META-INF/rights.xml')) adept = lambda tag: '{%s}%s' % (NSMAP['adept'], tag) expr = './/%s' % (adept('encryptedKey'),) bookkey = ''.join(rights.findtext(expr)) bookkey = aes.decrypt(bookkey.decode('base64')) bookkey = bookkey[:-ord(bookkey[-1])] encryption = inf.read('META-INF/encryption.xml') decryptor = Decryptor(bookkey[-16:], encryption) kwds = dict(compression=ZIP_DEFLATED, allowZip64=False) with closing(ZipFile(open(outpath, 'wb'), 'w', **kwds)) as outf: zi = ZipInfo('mimetype', compress_type=ZIP_STORED) outf.writestr(zi, inf.read('mimetype')) for path in namelist: data = inf.read(path) outf.writestr(path, decryptor.decrypt(path, data)) return 0 def cli_main(argv=sys.argv): progname = os.path.basename(argv[0]) if AES is None: print "%s: This script requires OpenSSL or PyCrypto, which must be installed " \ "separately. Read the top-of-script comment for details." % \ (progname,) return 1 if len(argv) != 4: print "usage: %s KEYFILE INBOOK OUTBOOK" % (progname,) return 1 keypath, inpath, outpath = argv[1:] return decryptBook(keypath, inpath, outpath) def gui_main(): root = Tkinter.Tk() if AES is None: root.withdraw() tkMessageBox.showerror( "Ignoble EPUB Decrypter", "This script requires OpenSSL or PyCrypto, which must be installed " "separately. Read the top-of-script comment for details.") return 1 root.title('Ignoble EPUB Decrypter') root.resizable(True, False) root.minsize(300, 0) DecryptionDialog(root).pack(fill=Tkconstants.X, expand=1) root.mainloop() return 0 if __name__ == '__main__': if len(sys.argv) > 1: sys.exit(cli_main()) sys.exit(gui_main())