Remove OpenSSL support; only support PyCryptodome

This allows us to clean up the code a lot.

On Windows, it isn't installed by default and
most of the time not be found at all.

On M1 Macs, the kernel will kill the process instead.

Closes #33.

DeDRM_plugin/ignoblekeyGenPassHash.py

@@ -2,7 +2,7 @@
 # -*- coding: utf-8 -*-
 
 # ignoblekeyGenPassHash.py
-# Copyright © 2009-2020 i♥cabbages, Apprentice Harper et al.
+# Copyright © 2009-2022 i♥cabbages, Apprentice Harper et al.
 
 # Released under the terms of the GNU General Public Licence, version 3
 # <http://www.gnu.org/licenses/>
@@ -31,19 +31,25 @@
 #   2.7 - Work if TkInter is missing
 #   2.8 - Fix bug in stand-alone use (import tkFileDialog)
 #   3.0 - Added Python 3 compatibility for calibre 5.0
+#   3.1 - Remove OpenSSL support, only PyCryptodome is supported now
 
 """
 Generate Barnes & Noble EPUB user key from name and credit card number.
 """
 
 __license__ = 'GPL v3'
-__version__ = "3.0"
+__version__ = "3.1"
 
 import sys
 import os
 import hashlib
 import base64
 
+try:
+    from Cryptodome.Cipher import AES
+except ImportError:
+    from Crypto.Cipher import AES
+
 # Wrap a stream so that output gets flushed immediately
 # and also make sure that any unicode strings get
 # encoded using "replace" before writing them.
@@ -114,87 +120,6 @@ def unicode_argv():
 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 iswindows:
-        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_set_encrypt_key = F(c_int, 'AES_set_encrypt_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, iv):
-            self._blocksize = len(userkey)
-            self._iv = iv
-            key = self._key = AES_KEY()
-            rv = AES_set_encrypt_key(userkey, len(userkey) * 8, key)
-            if rv < 0:
-                raise IGNOBLEError('Failed to initialize AES Encrypt key')
-
-        def encrypt(self, data):
-            out = create_string_buffer(len(data))
-            rv = AES_cbc_encrypt(data, out, len(data), self._key, self._iv, 1)
-            if rv == 0:
-                raise IGNOBLEError('AES encryption failed')
-            return out.raw
-
-    return AES
-
-def _load_crypto_pycrypto():
-    from Crypto.Cipher import AES as _AES
-
-    class AES(object):
-        def __init__(self, key, iv):
-            self._aes = _AES.new(key, _AES.MODE_CBC, iv)
-
-        def encrypt(self, data):
-            return self._aes.encrypt(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()
-
 def normalize_name(name):
     return ''.join(x for x in name.lower() if x != ' ')
 
@@ -215,8 +140,7 @@ def generate_key(name, ccn):
     name_sha = hashlib.sha1(name).digest()[:16]
     ccn_sha = hashlib.sha1(ccn).digest()[:16]
     both_sha = hashlib.sha1(name + ccn).digest()
-    aes = AES(ccn_sha, name_sha)
-    crypt = aes.encrypt(both_sha + (b'\x0c' * 0x0c))
+    crypt = AES.new(ccn_sha, AES.MODE_CBC, name_sha).encrypt(both_sha + (b'\x0c' * 0x0c))
     userkey = hashlib.sha1(crypt).digest()
     return base64.b64encode(userkey)
 
@@ -226,11 +150,6 @@ def cli_main():
     sys.stderr=SafeUnbuffered(sys.stderr)
     argv=unicode_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: {0} <Name> <CC#> <keyfileout.b64>".format(progname))
         return 1
@@ -316,13 +235,6 @@ def gui_main():
             self.status['text'] = "Keyfile successfully generated"
 
     root = tkinter.Tk()
-    if AES is None:
-        root.withdraw()
-        tkinter.messagebox.showerror(
-            "Ignoble EPUB Keyfile Generator",
-            "This script requires OpenSSL or PyCrypto, which must be installed "
-            "separately.  Read the top-of-script comment for details.")
-        return 1
     root.title("Barnes & Noble ePub Keyfile Generator v.{0}".format(__version__))
     root.resizable(True, False)
     root.minsize(300, 0)