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         init_length = seconds / 2 * 12 + 20*1000
 271         duration = "PT"+str(seconds)+".00S"
 272
 273         root = ET.Element('MPD')
 274         root.attrib['xmlns'] = 'urn:mpeg:dash:schema:mpd:2011'
 275         root.attrib['xmlns:cenc'] = 'urn:mpeg:cenc:2013'
 276         root.attrib['mediaPresentationDuration'] = duration
 277
 278         period = ET.SubElement(root, 'Period', start='PT0S', duration=duration)
 279
 280         # One Adaption Set for Video
 281         for video_track in manifest['videoTracks']:
 282             video_adaption_set = ET.SubElement(period, 'AdaptationSet', mimeType='video/mp4', contentType="video")
 283             # Content Protection
 284             protection = ET.SubElement(video_adaption_set, 'ContentProtection',
 285                           schemeIdUri='urn:uuid:EDEF8BA9-79D6-4ACE-A3C8-27DCD51D21ED')
 286             if pssh is not '':
 287                 ET.SubElement(protection, 'cenc:pssh').text = pssh
 288
 289             for downloadable in video_track['downloadables']:
 290
 291                 codec = 'h264'
 292                 if 'hevc' in downloadable['contentProfile']:
 293                     codec = 'hevc'
 294
 295                 hdcp_versions = '0.0'
 296                 for hdcp in downloadable['hdcpVersions']:
 297                     if hdcp != 'none':
 298                         hdcp_versions = hdcp
 299
 300                 rep = ET.SubElement(video_adaption_set, 'Representation',
 301                                     width=str(downloadable['width']),
 302                                     height=str(downloadable['height']),
 303                                     bandwidth=str(downloadable['bitrate']*1024),
 304                                     hdcp=hdcp_versions,
 305                                     nflxContentProfile=str(downloadable['contentProfile']),
 306                                     codecs=codec,
 307                                     mimeType='video/mp4')
 308
 309                 #BaseURL
 310                 ET.SubElement(rep, 'BaseURL').text = self.__get_base_url(downloadable['urls'])
 311                 # Init an Segment block
 312                 segment_base = ET.SubElement(rep, 'SegmentBase', indexRange="0-"+str(init_length), indexRangeExact="true")
 313                 ET.SubElement(segment_base, 'Initialization', range='0-'+str(init_length))
 314
 315
 316
 317         # Multiple Adaption Set for audio
 318         for audio_track in manifest['audioTracks']:
 319             audio_adaption_set = ET.SubElement(period, 'AdaptationSet',
 320                                                lang=audio_track['bcp47'],
 321                                                contentType='audio',
 322                                                mimeType='audio/mp4')
 323             for downloadable in audio_track['downloadables']:
 324                 codec = 'aac'
 325                 print downloadable
 326                 if downloadable['contentProfile'] == 'ddplus-2.0-dash' or downloadable['contentProfile'] == 'ddplus-5.1-dash':
 327                     codec = 'ec-3'
 328                 print "codec is: " + codec
 329                 rep = ET.SubElement(audio_adaption_set, 'Representation',
 330                                     codecs=codec,
 331                                     bandwidth=str(downloadable['bitrate']*1024),
 332                                     mimeType='audio/mp4')
 333
 334                 #AudioChannel Config
 335                 ET.SubElement(rep, 'AudioChannelConfiguration',
 336                               schemeIdUri='urn:mpeg:dash:23003:3:audio_channel_configuration:2011',
 337                               value=str(audio_track['channelsCount']))
 338
 339                 #BaseURL
 340                 ET.SubElement(rep, 'BaseURL').text = self.__get_base_url(downloadable['urls'])
 341                 # Index range
 342                 segment_base = ET.SubElement(rep, 'SegmentBase', indexRange="0-"+str(init_length), indexRangeExact="true")
 343                 ET.SubElement(segment_base, 'Initialization', range='0-'+str(init_length))
 344
 345
 346         xml = ET.tostring(root, encoding='utf-8', method='xml')
 347         xml = xml.replace('\n', '').replace('\r', '')
 348         return xml
 349
 350     def __get_base_url(self, urls):
 351         for key in urls:
 352             return urls[key]
 353
 354     def __parse_chunked_msl_response(self, message):
 355         i = 0
 356         opencount = 0
 357         closecount = 0
 358         header = ""
 359         payloads = []
 360         old_end = 0
 361
 362         while i < len(message):
 363             if message[i] == '{':
 364                 opencount = opencount + 1
 365             if message[i] == '}':
 366                 closecount = closecount + 1
 367             if opencount == closecount:
 368                 if header == "":
 369                     header = message[:i]
 370                     old_end = i + 1
 371                 else:
 372                     payloads.append(message[old_end:i + 1])
 373             i += 1
 374
 375         return {
 376             'header': header,
 377             'payloads': payloads
 378         }
 379
 380     def __generate_msl_request_data(self, data):
 381         header_encryption_envelope = self.__encrypt(self.__generate_msl_header())
 382         header = {
 383             'headerdata': base64.standard_b64encode(header_encryption_envelope),
 384             'signature': self.__sign(header_encryption_envelope),
 385             'mastertoken': self.mastertoken,
 386         }
 387
 388         # Serialize the given Data
 389         serialized_data = json.dumps(data)
 390         serialized_data = serialized_data.replace('"', '\\"')
 391         serialized_data = '[{},{"headers":{},"path":"/cbp/cadmium-13","payload":{"data":"' + serialized_data + '"},"query":""}]\n'
 392
 393         compressed_data = self.__compress_data(serialized_data)
 394
 395         # Create FIRST Payload Chunks
 396         first_payload = {
 397             "messageid": self.current_message_id,
 398             "data": compressed_data,
 399             "compressionalgo": "GZIP",
 400             "sequencenumber": 1,
 401             "endofmsg": True
 402         }
 403         first_payload_encryption_envelope = self.__encrypt(json.dumps(first_payload))
 404         first_payload_chunk = {
 405             'payload': base64.standard_b64encode(first_payload_encryption_envelope),
 406             'signature': self.__sign(first_payload_encryption_envelope),
 407         }
 408
 409         request_data = json.dumps(header) + json.dumps(first_payload_chunk)
 410         return request_data
 411
 412
 413
 414     def __compress_data(self, data):
 415         # GZIP THE DATA
 416         out = StringIO()
 417         with gzip.GzipFile(fileobj=out, mode="w") as f:
 418             f.write(data)
 419         return base64.standard_b64encode(out.getvalue())
 420
 421
 422     def __generate_msl_header(self, is_handshake=False, is_key_request=False, compressionalgo="GZIP", encrypt=True):
 423         """
 424         Function that generates a MSL header dict
 425         :return: The base64 encoded JSON String of the header
 426         """
 427         self.current_message_id = self.rndm.randint(0, pow(2, 52))
 428
 429         header_data = {
 430             'sender': self.esn,
 431             'handshake': is_handshake,
 432             'nonreplayable': False,
 433             'capabilities': {
 434                 'languages': ["en-US"],
 435                 'compressionalgos': []
 436             },
 437             'recipient': 'Netflix',
 438             'renewable': True,
 439             'messageid': self.current_message_id,
 440             'timestamp': 1467733923
 441         }
 442
 443         # Add compression algo if not empty
 444         if compressionalgo is not "":
 445             header_data['capabilities']['compressionalgos'].append(compressionalgo)
 446
 447         # If this is a keyrequest act diffrent then other requests
 448         if is_key_request:
 449             public_key = base64.standard_b64encode(self.rsa_key.publickey().exportKey(format='DER'))
 450             header_data['keyrequestdata'] = [{
 451                 'scheme': 'ASYMMETRIC_WRAPPED',
 452                 'keydata': {
 453                     'publickey': public_key,
 454                     'mechanism': 'JWK_RSA',
 455                     'keypairid': 'superKeyPair'
 456                 }
 457             }]
 458         else:
 459             if 'usertoken' in self.tokens:
 460                 pass
 461             else:
 462                 # Auth via email and password
 463                 header_data['userauthdata'] = {
 464                     'scheme': 'EMAIL_PASSWORD',
 465                     'authdata': {
 466                         'email': self.email,
 467                         'password': self.password
 468                     }
 469                 }
 470
 471         return json.dumps(header_data)
 472
 473
 474
 475     def __encrypt(self, plaintext):
 476         """
 477         Encrypt the given Plaintext with the encryption key
 478         :param plaintext:
 479         :return: Serialized JSON String of the encryption Envelope
 480         """
 481         iv = get_random_bytes(16)
 482         encryption_envelope = {
 483             'ciphertext': '',
 484             'keyid': self.esn + '_' + str(self.sequence_number),
 485             'sha256': 'AA==',
 486             'iv': base64.standard_b64encode(iv)
 487         }
 488         # Padd the plaintext
 489         plaintext = Padding.pad(plaintext, 16)
 490         # Encrypt the text
 491         cipher = AES.new(self.encryption_key, AES.MODE_CBC, iv)
 492         ciphertext = cipher.encrypt(plaintext)
 493         encryption_envelope['ciphertext'] = base64.standard_b64encode(ciphertext)
 494         return json.dumps(encryption_envelope)
 495
 496
 497     def __sign(self, text):
 498         """
 499         Calculates the HMAC signature for the given text with the current sign key and SHA256
 500         :param text:
 501         :return: Base64 encoded signature
 502         """
 503         signature = HMAC.new(self.sign_key, text, SHA256).digest()
 504         return base64.standard_b64encode(signature)
 505
 506
 507     def __perform_key_handshake(self):
 508         header = self.__generate_msl_header(is_key_request=True, is_handshake=True, compressionalgo="", encrypt=False)
 509         request = {
 510             'entityauthdata': {
 511                 'scheme': 'NONE',
 512                 'authdata': {
 513                     'identity': self.esn
 514                 }
 515             },
 516             'headerdata': base64.standard_b64encode(header),
 517             'signature': '',
 518         }
 519         self.kodi_helper.log(msg='Key Handshake Request:')
 520         self.kodi_helper.log(msg=json.dumps(request))
 521
 522         resp = self.session.post(self.endpoints['manifest'], json.dumps(request, sort_keys=True))
 523         if resp.status_code == 200:
 524             resp = resp.json()
 525             if 'errordata' in resp:
 526                 self.kodi_helper.log(msg='Key Exchange failed')
 527                 self.kodi_helper.log(msg=base64.standard_b64decode(resp['errordata']))
 528                 return False
 529             self.__parse_crypto_keys(json.JSONDecoder().decode(base64.standard_b64decode(resp['headerdata'])))
 530         else:
 531             self.kodi_helper.log(msg='Key Exchange failed')
 532             self.kodi_helper.log(msg=resp.text)
 533
 534     def __parse_crypto_keys(self, headerdata):
 535         self.__set_master_token(headerdata['keyresponsedata']['mastertoken'])
 536         # Init Decryption
 537         encrypted_encryption_key = base64.standard_b64decode(headerdata['keyresponsedata']['keydata']['encryptionkey'])
 538         encrypted_sign_key = base64.standard_b64decode(headerdata['keyresponsedata']['keydata']['hmackey'])
 539         cipher_rsa = PKCS1_OAEP.new(self.rsa_key)
 540
 541         # Decrypt encryption key
 542         encryption_key_data = json.JSONDecoder().decode(cipher_rsa.decrypt(encrypted_encryption_key))
 543         self.encryption_key = base64key_decode(encryption_key_data['k'])
 544
 545         # Decrypt sign key
 546         sign_key_data = json.JSONDecoder().decode(cipher_rsa.decrypt(encrypted_sign_key))
 547         self.sign_key = base64key_decode(sign_key_data['k'])
 548
 549         self.__save_msl_data()
 550         self.handshake_performed = True
 551
 552     def __load_msl_data(self):
 553         msl_data = json.JSONDecoder().decode(self.load_file(self.kodi_helper.msl_data_path, 'msl_data.json'))
 554         self.__set_master_token(msl_data['tokens']['mastertoken'])
 555         self.encryption_key = base64.standard_b64decode(msl_data['encryption_key'])
 556         self.sign_key = base64.standard_b64decode(msl_data['sign_key'])
 557
 558     def __save_msl_data(self):
 559         """
 560         Saves the keys and tokens in json file
 561         :return:
 562         """
 563         data = {
 564             "encryption_key": base64.standard_b64encode(self.encryption_key),
 565             'sign_key': base64.standard_b64encode(self.sign_key),
 566             'tokens': {
 567                 'mastertoken': self.mastertoken
 568             }
 569         }
 570         serialized_data = json.JSONEncoder().encode(data)
 571         self.save_file(self.kodi_helper.msl_data_path, 'msl_data.json', serialized_data)
 572
 573     def __set_master_token(self, master_token):
 574         self.mastertoken = master_token
 575         self.sequence_number = json.JSONDecoder().decode(base64.standard_b64decode(master_token['tokendata']))['sequencenumber']
 576
 577     def __load_rsa_keys(self):
 578         loaded_key = self.load_file(self.kodi_helper.msl_data_path, 'rsa_key.bin')
 579         self.rsa_key = RSA.importKey(loaded_key)
 580
 581     def __save_rsa_keys(self):
 582         self.kodi_helper.log(msg='Save RSA Keys')
 583         # Get the DER Base64 of the keys
 584         encrypted_key = self.rsa_key.exportKey()
 585         self.save_file(self.kodi_helper.msl_data_path, 'rsa_key.bin', encrypted_key)
 586
 587     @staticmethod
 588     def file_exists(msl_data_path, filename):
 589         """
 590         Checks if a given file exists
 591         :param filename: The filename
 592         :return: True if so
 593         """
 594         return os.path.isfile(msl_data_path + filename)
 595
 596     @staticmethod
 597     def save_file(msl_data_path, filename, content):
 598         """
 599         Saves the given content under given filename
 600         :param filename: The filename
 601         :param content: The content of the file
 602         """
 603         with open(msl_data_path + filename, 'w') as file_:
 604             file_.write(content)
 605             file_.flush()
 606
 607     @staticmethod
 608     def load_file(msl_data_path, filename):
 609         """
 610         Loads the content of a given filename
 611         :param filename: The file to load
 612         :return: The content of the file
 613         """
 614         with open(msl_data_path + filename) as file_:
 615             file_content = file_.read()
 616         return file_content