resources/lib/MSL.py

   1 import base64
   2 import gzip
   3 import json
   4 import os
   5 import pprint
   6 import random
   7 from StringIO import StringIO
   8 import requests
   9 import zlib
  10
  11 import time
  12 from Cryptodome.PublicKey import RSA
  13 from Cryptodome.Cipher import PKCS1_OAEP
  14 from Cryptodome.Cipher import AES
  15 from Cryptodome.Random import get_random_bytes
  16 from Cryptodome.Hash import HMAC, SHA256
  17 from Cryptodome.Util import Padding
  18 import xml.etree.ElementTree as ET
  19
  20 pp = pprint.PrettyPrinter(indent=4)
  21
  22 def base64key_decode(payload):
  23     l = len(payload) % 4
  24     if l == 2:
  25         payload += '=='
  26     elif l == 3:
  27         payload += '='
  28     elif l != 0:
  29         raise ValueError('Invalid base64 string')
  30     return base64.urlsafe_b64decode(payload.encode('utf-8'))
  31
  32
  33 class MSL:
  34     handshake_performed = False  # Is a handshake already performed and the keys loaded
  35     last_drm_context = ''
  36     last_playback_context = ''
  37     #esn = "NFCDCH-LX-CQE0NU6PA5714R25VPLXVU2A193T36"
  38     esn = "WWW-BROWSE-D7GW1G4NPXGR1F0X1H3EQGY3V1F5WE"
  39     #esn = "NFCDIE-02-DCH84Q2EK3N6VFVQJ0NLRQ27498N0F"
  40     current_message_id = 0
  41     session = requests.session()
  42     rndm = random.SystemRandom()
  43     tokens = []
  44     endpoints = {
  45         'manifest': 'http://www.netflix.com/api/msl/NFCDCH-LX/cadmium/manifest',
  46         'license': 'http://www.netflix.com/api/msl/NFCDCH-LX/cadmium/license'
  47     }
  48
  49     def __init__(self, email, password, kodi_helper):
  50         """
  51         The Constructor checks for already existing crypto Keys.
  52         If they exist it will load the existing keys
  53         """
  54         self.email = email
  55         self.password = password
  56         self.kodi_helper = kodi_helper
  57         try:
  58             os.mkdir(self.kodi_helper.msl_data_path)
  59         except OSError:
  60             pass
  61
  62         if self.file_exists(self.kodi_helper.msl_data_path, 'msl_data.json'):
  63             self.kodi_helper.log(msg='MSL Data exists. Use old Tokens.')
  64             self.__load_msl_data()
  65             self.handshake_performed = True
  66         elif self.file_exists(self.kodi_helper.msl_data_path, 'rsa_key.bin'):
  67             self.kodi_helper.log(msg='RSA Keys do already exist load old ones')
  68             self.__load_rsa_keys()
  69             self.__perform_key_handshake()
  70         else:
  71             self.kodi_helper.log(msg='Create new RSA Keys')
  72             # Create new Key Pair and save
  73             self.rsa_key = RSA.generate(2048)
  74             self.__save_rsa_keys()
  75             self.__perform_key_handshake()
  76
  77     def load_manifest(self, viewable_id):
  78         """
  79         Loads the manifets for the given viewable_id and returns a mpd-XML-Manifest
  80         :param viewable_id: The id of of the viewable
  81         :return: MPD XML Manifest or False if no success
  82         """
  83         manifest_request_data = {
  84             'method': 'manifest',
  85             'lookupType': 'PREPARE',
  86             'viewableIds': [viewable_id],
  87             'profiles': [
  88                 "playready-h264bpl30-dash",
  89                 "playready-h264mpl30-dash",
  90                 "playready-h264mpl31-dash",
  91                 "playready-h264mpl40-dash",
  92                 # "hevc-main-L30-dash-cenc",
  93                 # "hevc-main-L31-dash-cenc",
  94                 # "hevc-main-L40-dash-cenc",
  95                 # "hevc-main-L41-dash-cenc",
  96                 # "hevc-main-L50-dash-cenc",
  97                 # "hevc-main-L51-dash-cenc",
  98                 # "hevc-main10-L30-dash-cenc",
  99                 # "hevc-main10-L31-dash-cenc",
 100                 # "hevc-main10-L40-dash-cenc",
 101                 # "hevc-main10-L41-dash-cenc",
 102                 # "hevc-main10-L50-dash-cenc",
 103                 # "hevc-main10-L51-dash-cenc",
 104                 # "hevc-main10-L30-dash-cenc-prk",
 105                 # "hevc-main10-L31-dash-cenc-prk",
 106                 # "hevc-main10-L40-dash-cenc-prk",
 107                 # "hevc-main10-L41-dash-cenc-prk",
 108                 # "hevc-main-L30-L31-dash-cenc-tl",
 109                 # "hevc-main-L31-L40-dash-cenc-tl",
 110                 # "hevc-main-L40-L41-dash-cenc-tl",
 111                 # "hevc-main-L50-L51-dash-cenc-tl",
 112                 # "hevc-main10-L30-L31-dash-cenc-tl",
 113                 # "hevc-main10-L31-L40-dash-cenc-tl",
 114                 # "hevc-main10-L40-L41-dash-cenc-tl",
 115                 # "hevc-main10-L50-L51-dash-cenc-tl",
 116                 # "hevc-dv-main10-L30-dash-cenc",
 117                 # "hevc-dv-main10-L31-dash-cenc",
 118                 # "hevc-dv-main10-L40-dash-cenc",
 119                 # "hevc-dv-main10-L41-dash-cenc",
 120                 # "hevc-dv-main10-L50-dash-cenc",
 121                 # "hevc-dv-main10-L51-dash-cenc",
 122                 # "hevc-dv5-main10-L30-dash-cenc-prk",
 123                 # "hevc-dv5-main10-L31-dash-cenc-prk",
 124                 # "hevc-dv5-main10-L40-dash-cenc-prk",
 125                 # "hevc-dv5-main10-L41-dash-cenc-prk",
 126                 # "hevc-dv5-main10-L50-dash-cenc-prk",
 127                 # "hevc-dv5-main10-L51-dash-cenc-prk",
 128                 # "hevc-hdr-main10-L30-dash-cenc",
 129                 # "hevc-hdr-main10-L31-dash-cenc",
 130                 # "hevc-hdr-main10-L40-dash-cenc",
 131                 # "hevc-hdr-main10-L41-dash-cenc",
 132                 # "hevc-hdr-main10-L50-dash-cenc",
 133                 # "hevc-hdr-main10-L51-dash-cenc",
 134                 # "hevc-hdr-main10-L30-dash-cenc-prk",
 135                 # "hevc-hdr-main10-L31-dash-cenc-prk",
 136                 # "hevc-hdr-main10-L40-dash-cenc-prk",
 137                 # "hevc-hdr-main10-L41-dash-cenc-prk",
 138                 # "hevc-hdr-main10-L50-dash-cenc-prk",
 139                 # "hevc-hdr-main10-L51-dash-cenc-prk"
 140
 141                # 'playready-h264mpl30-dash',
 142                 #'playready-h264mpl31-dash',
 143                 #'playready-h264mpl40-dash',
 144                 #'hevc-main10-L41-dash-cenc',
 145                 #'hevc-main10-L50-dash-cenc',
 146                 #'hevc-main10-L51-dash-cenc',
 147
 148
 149
 150                 # Audio
 151                 'heaac-2-dash',
 152                 'ddplus-2.0-dash',
 153                 'ddplus-5.1-dash',
 154                 'dfxp-ls-sdh',
 155                 'simplesdh',
 156                 'nflx-cmisc',
 157                 'BIF240',
 158                 'BIF320'
 159             ],
 160             'drmSystem': 'widevine',
 161             'appId': '14673889385265',
 162             'sessionParams': {
 163                 'pinCapableClient': False,
 164                 'uiplaycontext': 'null'
 165             },
 166             'sessionId': '14673889385265',
 167             'trackId': 0,
 168             'flavor': 'PRE_FETCH',
 169             'secureUrls': False,
 170             'supportPreviewContent': True,
 171             'forceClearStreams': False,
 172             'languages': ['de-DE'],
 173             'clientVersion': '4.0004.899.011',
 174             'uiVersion': 'akira'
 175         }
 176         request_data = self.__generate_msl_request_data(manifest_request_data)
 177         resp = self.session.post(self.endpoints['manifest'], request_data)
 178
 179         try:
 180             # if the json() does not fail we have an error because the manifest response is a chuncked json response
 181             resp.json()
 182             self.kodi_helper.log(msg='Error getting Manifest: '+resp.text)
 183             return False
 184         except ValueError:
 185             # json() failed so parse the chunked response
 186             self.kodi_helper.log(msg='Got chunked Manifest Response: ' + resp.text)
 187             resp = self.__parse_chunked_msl_response(resp.text)
 188             self.kodi_helper.log(msg='Parsed chunked Response: ' + json.dumps(resp))
 189             data = self.__decrypt_payload_chunk(resp['payloads'][0])
 190             return self.__tranform_to_dash(data)
 191
 192     def get_license(self, challenge, sid):
 193         """
 194         Requests and returns a license for the given challenge and sid
 195         :param challenge: The base64 encoded challenge
 196         :param sid: The sid paired to the challengew
 197         :return: Base64 representation of the license key or False if no success
 198         """
 199         license_request_data = {
 200             'method': 'license',
 201             'licenseType': 'STANDARD',
 202             'clientVersion': '4.0004.899.011',
 203             'uiVersion': 'akira',
 204             'languages': ['de-DE'],
 205             'playbackContextId': self.last_playback_context,
 206             'drmContextIds': [self.last_drm_context],
 207             'challenges': [{
 208                 'dataBase64': challenge,
 209                 'sessionId': sid
 210             }],
 211             'clientTime': int(time.time()),
 212             'xid': int((int(time.time()) + 0.1612) * 1000)
 213
 214         }
 215         request_data = self.__generate_msl_request_data(license_request_data)
 216
 217         resp = self.session.post(self.endpoints['license'], request_data)
 218
 219         try:
 220             # If is valid json the request for the licnese failed
 221             resp.json()
 222             self.kodi_helper.log(msg='Error getting license: '+resp.text)
 223             return False
 224         except ValueError:
 225             # json() failed so we have a chunked json response
 226             resp = self.__parse_chunked_msl_response(resp.text)
 227             data = self.__decrypt_payload_chunk(resp['payloads'][0])
 228             if data['success'] is True:
 229                 return data['result']['licenses'][0]['data']
 230             else:
 231                 self.kodi_helper.log(msg='Error getting license: ' + json.dumps(data))
 232                 return False
 233
 234     def __decrypt_payload_chunk(self, payloadchunk):
 235         payloadchunk = json.JSONDecoder().decode(payloadchunk)
 236         encryption_envelope = json.JSONDecoder().decode(base64.standard_b64decode(payloadchunk['payload']))
 237         # Decrypt the text
 238         cipher = AES.new(self.encryption_key, AES.MODE_CBC, base64.standard_b64decode(encryption_envelope['iv']))
 239         plaintext = cipher.decrypt(base64.standard_b64decode(encryption_envelope['ciphertext']))
 240         # unpad the plaintext
 241         plaintext = json.JSONDecoder().decode(Padding.unpad(plaintext, 16))
 242         data = plaintext['data']
 243
 244         # uncompress data if compressed
 245         if plaintext['compressionalgo'] == 'GZIP':
 246             data = zlib.decompress(base64.standard_b64decode(data), 16 + zlib.MAX_WBITS)
 247         else:
 248             data = base64.standard_b64decode(data)
 249
 250         data = json.JSONDecoder().decode(data)[1]['payload']['data']
 251         data = base64.standard_b64decode(data)
 252         return json.JSONDecoder().decode(data)
 253
 254
 255     def __tranform_to_dash(self, manifest):
 256
 257         self.save_file(self.kodi_helper.msl_data_path, 'manifest.json', json.dumps(manifest))
 258         manifest = manifest['result']['viewables'][0]
 259
 260         self.last_playback_context = manifest['playbackContextId']
 261         self.last_drm_context = manifest['drmContextId']
 262
 263         #Check for pssh
 264         pssh = ''
 265         if 'psshb64' in manifest:
 266             if len(manifest['psshb64']) >= 1:
 267                 pssh = manifest['psshb64'][0]
 268
 269         seconds = manifest['runtime']/1000
 270         duration = "PT"+str(seconds)+".00S"
 271
 272         root = ET.Element('MPD')
 273         root.attrib['xmlns'] = 'urn:mpeg:dash:schema:mpd:2011'
 274         root.attrib['xmlns:cenc'] = 'urn:mpeg:cenc:2013'
 275         root.attrib['mediaPresentationDuration'] = duration
 276
 277         period = ET.SubElement(root, 'Period', start='PT0S', duration=duration)
 278
 279         # One Adaption Set for Video
 280         for video_track in manifest['videoTracks']:
 281             video_adaption_set = ET.SubElement(period, 'AdaptationSet', mimeType='video/mp4', contentType="video")
 282             # Content Protection
 283             protection = ET.SubElement(video_adaption_set, 'ContentProtection',
 284                           schemeIdUri='urn:uuid:EDEF8BA9-79D6-4ACE-A3C8-27DCD51D21ED')
 285             if pssh is not '':
 286                 ET.SubElement(protection, 'cenc:pssh').text = pssh
 287
 288             for downloadable in video_track['downloadables']:
 289
 290                 hdcp_versions = '0.0'
 291                 for hdcp in downloadable['hdcpVersions']:
 292                     if hdcp != 'none':
 293                         hdcp_versions = hdcp
 294
 295                 rep = ET.SubElement(video_adaption_set, 'Representation',
 296                                     width=str(downloadable['width']),
 297                                     height=str(downloadable['height']),
 298                                     bandwidth=str(downloadable['bitrate']*1024),
 299                                     hdcp=hdcp_versions,
 300                                     nflxContentProfile=str(downloadable['contentProfile']),
 301                                     codecs='h264',
 302                                     mimeType='video/mp4')
 303
 304                 #BaseURL
 305                 ET.SubElement(rep, 'BaseURL').text = self.__get_base_url(downloadable['urls'])
 306                 # Init an Segment block
 307                 segment_base = ET.SubElement(rep, 'SegmentBase', indexRange="0-60000", indexRangeExact="true")
 308                 ET.SubElement(segment_base, 'Initialization', range='0-60000')
 309
 310
 311
 312         # Multiple Adaption Set for audio
 313         for audio_track in manifest['audioTracks']:
 314             audio_adaption_set = ET.SubElement(period, 'AdaptationSet',
 315                                                lang=audio_track['bcp47'],
 316                                                contentType='audio',
 317                                                mimeType='audio/mp4')
 318             for downloadable in audio_track['downloadables']:
 319                 codec = 'aac'
 320                 print downloadable
 321                 if downloadable['contentProfile'] == 'ddplus-2.0-dash' or downloadable['contentProfile'] == 'ddplus-5.1-dash':
 322                     codec = 'ec-3'
 323                 print "codec is: " + codec
 324                 rep = ET.SubElement(audio_adaption_set, 'Representation',
 325                                     codecs=codec,
 326                                     bandwidth=str(downloadable['bitrate']*1024),
 327                                     mimeType='audio/mp4')
 328
 329                 #AudioChannel Config
 330                 ET.SubElement(rep, 'AudioChannelConfiguration',
 331                               schemeIdUri='urn:mpeg:dash:23003:3:audio_channel_configuration:2011',
 332                               value=str(audio_track['channelsCount']))
 333
 334                 #BaseURL
 335                 ET.SubElement(rep, 'BaseURL').text = self.__get_base_url(downloadable['urls'])
 336                 # Index range
 337                 segment_base = ET.SubElement(rep, 'SegmentBase', indexRange="0-60000", indexRangeExact="true")
 338                 ET.SubElement(segment_base, 'Initialization', range='0-60000')
 339
 340
 341         xml = ET.tostring(root, encoding='utf-8', method='xml')
 342         xml = xml.replace('\n', '').replace('\r', '')
 343         return xml
 344
 345     def __get_base_url(self, urls):
 346         for key in urls:
 347             return urls[key]
 348
 349     def __parse_chunked_msl_response(self, message):
 350         i = 0
 351         opencount = 0
 352         closecount = 0
 353         header = ""
 354         payloads = []
 355         old_end = 0
 356
 357         while i < len(message):
 358             if message[i] == '{':
 359                 opencount = opencount + 1
 360             if message[i] == '}':
 361                 closecount = closecount + 1
 362             if opencount == closecount:
 363                 if header == "":
 364                     header = message[:i]
 365                     old_end = i + 1
 366                 else:
 367                     payloads.append(message[old_end:i + 1])
 368             i += 1
 369
 370         return {
 371             'header': header,
 372             'payloads': payloads
 373         }
 374
 375     def __generate_msl_request_data(self, data):
 376         header_encryption_envelope = self.__encrypt(self.__generate_msl_header())
 377         header = {
 378             'headerdata': base64.standard_b64encode(header_encryption_envelope),
 379             'signature': self.__sign(header_encryption_envelope),
 380             'mastertoken': self.mastertoken,
 381         }
 382
 383         # Serialize the given Data
 384         serialized_data = json.dumps(data)
 385         serialized_data = serialized_data.replace('"', '\\"')
 386         serialized_data = '[{},{"headers":{},"path":"/cbp/cadmium-13","payload":{"data":"' + serialized_data + '"},"query":""}]\n'
 387
 388         compressed_data = self.__compress_data(serialized_data)
 389
 390         # Create FIRST Payload Chunks
 391         first_payload = {
 392             "messageid": self.current_message_id,
 393             "data": compressed_data,
 394             "compressionalgo": "GZIP",
 395             "sequencenumber": 1,
 396             "endofmsg": True
 397         }
 398         first_payload_encryption_envelope = self.__encrypt(json.dumps(first_payload))
 399         first_payload_chunk = {
 400             'payload': base64.standard_b64encode(first_payload_encryption_envelope),
 401             'signature': self.__sign(first_payload_encryption_envelope),
 402         }
 403
 404         request_data = json.dumps(header) + json.dumps(first_payload_chunk)
 405         return request_data
 406
 407
 408
 409     def __compress_data(self, data):
 410         # GZIP THE DATA
 411         out = StringIO()
 412         with gzip.GzipFile(fileobj=out, mode="w") as f:
 413             f.write(data)
 414         return base64.standard_b64encode(out.getvalue())
 415
 416
 417     def __generate_msl_header(self, is_handshake=False, is_key_request=False, compressionalgo="GZIP", encrypt=True):
 418         """
 419         Function that generates a MSL header dict
 420         :return: The base64 encoded JSON String of the header
 421         """
 422         self.current_message_id = self.rndm.randint(0, pow(2, 52))
 423
 424         header_data = {
 425             'sender': self.esn,
 426             'handshake': is_handshake,
 427             'nonreplayable': False,
 428             'capabilities': {
 429                 'languages': ["en-US"],
 430                 'compressionalgos': []
 431             },
 432             'recipient': 'Netflix',
 433             'renewable': True,
 434             'messageid': self.current_message_id,
 435             'timestamp': 1467733923
 436         }
 437
 438         # Add compression algo if not empty
 439         if compressionalgo is not "":
 440             header_data['capabilities']['compressionalgos'].append(compressionalgo)
 441
 442         # If this is a keyrequest act diffrent then other requests
 443         if is_key_request:
 444             public_key = base64.standard_b64encode(self.rsa_key.publickey().exportKey(format='DER'))
 445             header_data['keyrequestdata'] = [{
 446                 'scheme': 'ASYMMETRIC_WRAPPED',
 447                 'keydata': {
 448                     'publickey': public_key,
 449                     'mechanism': 'JWK_RSA',
 450                     'keypairid': 'superKeyPair'
 451                 }
 452             }]
 453         else:
 454             if 'usertoken' in self.tokens:
 455                 pass
 456             else:
 457                 # Auth via email and password
 458                 header_data['userauthdata'] = {
 459                     'scheme': 'EMAIL_PASSWORD',
 460                     'authdata': {
 461                         'email': self.email,
 462                         'password': self.password
 463                     }
 464                 }
 465
 466         return json.dumps(header_data)
 467
 468
 469
 470     def __encrypt(self, plaintext):
 471         """
 472         Encrypt the given Plaintext with the encryption key
 473         :param plaintext:
 474         :return: Serialized JSON String of the encryption Envelope
 475         """
 476         iv = get_random_bytes(16)
 477         encryption_envelope = {
 478             'ciphertext': '',
 479             'keyid': self.esn + '_' + str(self.sequence_number),
 480             'sha256': 'AA==',
 481             'iv': base64.standard_b64encode(iv)
 482         }
 483         # Padd the plaintext
 484         plaintext = Padding.pad(plaintext, 16)
 485         # Encrypt the text
 486         cipher = AES.new(self.encryption_key, AES.MODE_CBC, iv)
 487         ciphertext = cipher.encrypt(plaintext)
 488         encryption_envelope['ciphertext'] = base64.standard_b64encode(ciphertext)
 489         return json.dumps(encryption_envelope)
 490
 491
 492     def __sign(self, text):
 493         """
 494         Calculates the HMAC signature for the given text with the current sign key and SHA256
 495         :param text:
 496         :return: Base64 encoded signature
 497         """
 498         signature = HMAC.new(self.sign_key, text, SHA256).digest()
 499         return base64.standard_b64encode(signature)
 500
 501
 502     def __perform_key_handshake(self):
 503         header = self.__generate_msl_header(is_key_request=True, is_handshake=True, compressionalgo="", encrypt=False)
 504         request = {
 505             'entityauthdata': {
 506                 'scheme': 'NONE',
 507                 'authdata': {
 508                     'identity': self.esn
 509                 }
 510             },
 511             'headerdata': base64.standard_b64encode(header),
 512             'signature': '',
 513         }
 514         self.kodi_helper.log(msg='Key Handshake Request:')
 515         self.kodi_helper.log(msg=json.dumps(request))
 516
 517         resp = self.session.post(self.endpoints['manifest'], json.dumps(request, sort_keys=True))
 518         if resp.status_code == 200:
 519             resp = resp.json()
 520             if 'errordata' in resp:
 521                 self.kodi_helper.log(msg='Key Exchange failed')
 522                 self.kodi_helper.log(msg=base64.standard_b64decode(resp['errordata']))
 523                 return False
 524             self.__parse_crypto_keys(json.JSONDecoder().decode(base64.standard_b64decode(resp['headerdata'])))
 525         else:
 526             self.kodi_helper.log(msg='Key Exchange failed')
 527             self.kodi_helper.log(msg=resp.text)
 528
 529     def __parse_crypto_keys(self, headerdata):
 530         self.__set_master_token(headerdata['keyresponsedata']['mastertoken'])
 531         # Init Decryption
 532         encrypted_encryption_key = base64.standard_b64decode(headerdata['keyresponsedata']['keydata']['encryptionkey'])
 533         encrypted_sign_key = base64.standard_b64decode(headerdata['keyresponsedata']['keydata']['hmackey'])
 534         cipher_rsa = PKCS1_OAEP.new(self.rsa_key)
 535
 536         # Decrypt encryption key
 537         encryption_key_data = json.JSONDecoder().decode(cipher_rsa.decrypt(encrypted_encryption_key))
 538         self.encryption_key = base64key_decode(encryption_key_data['k'])
 539
 540         # Decrypt sign key
 541         sign_key_data = json.JSONDecoder().decode(cipher_rsa.decrypt(encrypted_sign_key))
 542         self.sign_key = base64key_decode(sign_key_data['k'])
 543
 544         self.__save_msl_data()
 545         self.handshake_performed = True
 546
 547     def __load_msl_data(self):
 548         msl_data = json.JSONDecoder().decode(self.load_file(self.kodi_helper.msl_data_path, 'msl_data.json'))
 549         self.__set_master_token(msl_data['tokens']['mastertoken'])
 550         self.encryption_key = base64.standard_b64decode(msl_data['encryption_key'])
 551         self.sign_key = base64.standard_b64decode(msl_data['sign_key'])
 552
 553     def __save_msl_data(self):
 554         """
 555         Saves the keys and tokens in json file
 556         :return:
 557         """
 558         data = {
 559             "encryption_key": base64.standard_b64encode(self.encryption_key),
 560             'sign_key': base64.standard_b64encode(self.sign_key),
 561             'tokens': {
 562                 'mastertoken': self.mastertoken
 563             }
 564         }
 565         serialized_data = json.JSONEncoder().encode(data)
 566         self.save_file(self.kodi_helper.msl_data_path, 'msl_data.json', serialized_data)
 567
 568     def __set_master_token(self, master_token):
 569         self.mastertoken = master_token
 570         self.sequence_number = json.JSONDecoder().decode(base64.standard_b64decode(master_token['tokendata']))['sequencenumber']
 571
 572     def __load_rsa_keys(self):
 573         loaded_key = self.load_file(self.kodi_helper.msl_data_path, 'rsa_key.bin')
 574         self.rsa_key = RSA.importKey(loaded_key)
 575
 576     def __save_rsa_keys(self):
 577         self.kodi_helper.log(msg='Save RSA Keys')
 578         # Get the DER Base64 of the keys
 579         encrypted_key = self.rsa_key.exportKey()
 580         self.save_file(self.kodi_helper.msl_data_path, 'rsa_key.bin', encrypted_key)
 581
 582     @staticmethod
 583     def file_exists(msl_data_path, filename):
 584         """
 585         Checks if a given file exists
 586         :param filename: The filename
 587         :return: True if so
 588         """
 589         return os.path.isfile(msl_data_path + filename)
 590
 591     @staticmethod
 592     def save_file(msl_data_path, filename, content):
 593         """
 594         Saves the given content under given filename
 595         :param filename: The filename
 596         :param content: The content of the file
 597         """
 598         with open(msl_data_path + filename, 'w') as file_:
 599             file_.write(content)
 600             file_.flush()
 601
 602     @staticmethod
 603     def load_file(msl_data_path, filename):
 604         """
 605         Loads the content of a given filename
 606         :param filename: The file to load
 607         :return: The content of the file
 608         """
 609         with open(msl_data_path + filename) as file_:
 610             file_content = file_.read()
 611         return file_content