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, 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.kodi_helper = kodi_helper
  55         try:
  56             os.mkdir(self.kodi_helper.msl_data_path)
  57         except OSError:
  58             pass
  59
  60         if self.file_exists(self.kodi_helper.msl_data_path, 'msl_data.json'):
  61             self.kodi_helper.log(msg='MSL Data exists. Use old Tokens.')
  62             self.__load_msl_data()
  63             self.handshake_performed = True
  64         elif self.file_exists(self.kodi_helper.msl_data_path, 'rsa_key.bin'):
  65             self.kodi_helper.log(msg='RSA Keys do already exist load old ones')
  66             self.__load_rsa_keys()
  67             self.__perform_key_handshake()
  68         else:
  69             self.kodi_helper.log(msg='Create new RSA Keys')
  70             # Create new Key Pair and save
  71             self.rsa_key = RSA.generate(2048)
  72             self.__save_rsa_keys()
  73             self.__perform_key_handshake()
  74
  75     def load_manifest(self, viewable_id):
  76         """
  77         Loads the manifets for the given viewable_id and returns a mpd-XML-Manifest
  78         :param viewable_id: The id of of the viewable
  79         :return: MPD XML Manifest or False if no success
  80         """
  81         manifest_request_data = {
  82             'method': 'manifest',
  83             'lookupType': 'PREPARE',
  84             'viewableIds': [viewable_id],
  85             'profiles': [
  86                 "playready-h264bpl30-dash",
  87                 "playready-h264mpl30-dash",
  88                 "playready-h264mpl31-dash",
  89                 "playready-h264mpl40-dash",
  90                 # "hevc-main-L30-dash-cenc",
  91                 # "hevc-main-L31-dash-cenc",
  92                 # "hevc-main-L40-dash-cenc",
  93                 # "hevc-main-L41-dash-cenc",
  94                 # "hevc-main-L50-dash-cenc",
  95                 # "hevc-main-L51-dash-cenc",
  96                 # "hevc-main10-L30-dash-cenc",
  97                 # "hevc-main10-L31-dash-cenc",
  98                 # "hevc-main10-L40-dash-cenc",
  99                 # "hevc-main10-L41-dash-cenc",
 100                 # "hevc-main10-L50-dash-cenc",
 101                 # "hevc-main10-L51-dash-cenc",
 102                 # "hevc-main10-L30-dash-cenc-prk",
 103                 # "hevc-main10-L31-dash-cenc-prk",
 104                 # "hevc-main10-L40-dash-cenc-prk",
 105                 # "hevc-main10-L41-dash-cenc-prk",
 106                 # "hevc-main-L30-L31-dash-cenc-tl",
 107                 # "hevc-main-L31-L40-dash-cenc-tl",
 108                 # "hevc-main-L40-L41-dash-cenc-tl",
 109                 # "hevc-main-L50-L51-dash-cenc-tl",
 110                 # "hevc-main10-L30-L31-dash-cenc-tl",
 111                 # "hevc-main10-L31-L40-dash-cenc-tl",
 112                 # "hevc-main10-L40-L41-dash-cenc-tl",
 113                 # "hevc-main10-L50-L51-dash-cenc-tl",
 114                 # "hevc-dv-main10-L30-dash-cenc",
 115                 # "hevc-dv-main10-L31-dash-cenc",
 116                 # "hevc-dv-main10-L40-dash-cenc",
 117                 # "hevc-dv-main10-L41-dash-cenc",
 118                 # "hevc-dv-main10-L50-dash-cenc",
 119                 # "hevc-dv-main10-L51-dash-cenc",
 120                 # "hevc-dv5-main10-L30-dash-cenc-prk",
 121                 # "hevc-dv5-main10-L31-dash-cenc-prk",
 122                 # "hevc-dv5-main10-L40-dash-cenc-prk",
 123                 # "hevc-dv5-main10-L41-dash-cenc-prk",
 124                 # "hevc-dv5-main10-L50-dash-cenc-prk",
 125                 # "hevc-dv5-main10-L51-dash-cenc-prk",
 126                 # "hevc-hdr-main10-L30-dash-cenc",
 127                 # "hevc-hdr-main10-L31-dash-cenc",
 128                 # "hevc-hdr-main10-L40-dash-cenc",
 129                 # "hevc-hdr-main10-L41-dash-cenc",
 130                 # "hevc-hdr-main10-L50-dash-cenc",
 131                 # "hevc-hdr-main10-L51-dash-cenc",
 132                 # "hevc-hdr-main10-L30-dash-cenc-prk",
 133                 # "hevc-hdr-main10-L31-dash-cenc-prk",
 134                 # "hevc-hdr-main10-L40-dash-cenc-prk",
 135                 # "hevc-hdr-main10-L41-dash-cenc-prk",
 136                 # "hevc-hdr-main10-L50-dash-cenc-prk",
 137                 # "hevc-hdr-main10-L51-dash-cenc-prk"
 138
 139                # 'playready-h264mpl30-dash',
 140                 #'playready-h264mpl31-dash',
 141                 #'playready-h264mpl40-dash',
 142                 #'hevc-main10-L41-dash-cenc',
 143                 #'hevc-main10-L50-dash-cenc',
 144                 #'hevc-main10-L51-dash-cenc',
 145
 146
 147
 148                 # Audio
 149                 'heaac-2-dash',
 150                 'ddplus-2.0-dash',
 151                 'ddplus-5.1-dash',
 152                 'dfxp-ls-sdh',
 153                 'simplesdh',
 154                 'nflx-cmisc',
 155                 'BIF240',
 156                 'BIF320'
 157             ],
 158             'drmSystem': 'widevine',
 159             'appId': '14673889385265',
 160             'sessionParams': {
 161                 'pinCapableClient': False,
 162                 'uiplaycontext': 'null'
 163             },
 164             'sessionId': '14673889385265',
 165             'trackId': 0,
 166             'flavor': 'PRE_FETCH',
 167             'secureUrls': False,
 168             'supportPreviewContent': True,
 169             'forceClearStreams': False,
 170             'languages': ['de-DE'],
 171             'clientVersion': '4.0004.899.011',
 172             'uiVersion': 'akira'
 173         }
 174         request_data = self.__generate_msl_request_data(manifest_request_data)
 175         resp = self.session.post(self.endpoints['manifest'], request_data)
 176
 177         try:
 178             # if the json() does not fail we have an error because the manifest response is a chuncked json response
 179             resp.json()
 180             self.kodi_helper.log(msg='Error getting Manifest: '+resp.text)
 181             return False
 182         except ValueError:
 183             # json() failed so parse the chunked response
 184             self.kodi_helper.log(msg='Got chunked Manifest Response: ' + resp.text)
 185             resp = self.__parse_chunked_msl_response(resp.text)
 186             self.kodi_helper.log(msg='Parsed chunked Response: ' + json.dumps(resp))
 187             data = self.__decrypt_payload_chunk(resp['payloads'][0])
 188             return self.__tranform_to_dash(data)
 189
 190     def get_license(self, challenge, sid):
 191         """
 192         Requests and returns a license for the given challenge and sid
 193         :param challenge: The base64 encoded challenge
 194         :param sid: The sid paired to the challengew
 195         :return: Base64 representation of the license key or False if no success
 196         """
 197         license_request_data = {
 198             'method': 'license',
 199             'licenseType': 'STANDARD',
 200             'clientVersion': '4.0004.899.011',
 201             'uiVersion': 'akira',
 202             'languages': ['de-DE'],
 203             'playbackContextId': self.last_playback_context,
 204             'drmContextIds': [self.last_drm_context],
 205             'challenges': [{
 206                 'dataBase64': challenge,
 207                 'sessionId': sid
 208             }],
 209             'clientTime': int(time.time()),
 210             'xid': int((int(time.time()) + 0.1612) * 1000)
 211
 212         }
 213         request_data = self.__generate_msl_request_data(license_request_data)
 214
 215         resp = self.session.post(self.endpoints['license'], request_data)
 216
 217         try:
 218             # If is valid json the request for the licnese failed
 219             resp.json()
 220             self.kodi_helper.log(msg='Error getting license: '+resp.text)
 221             return False
 222         except ValueError:
 223             # json() failed so we have a chunked json response
 224             resp = self.__parse_chunked_msl_response(resp.text)
 225             data = self.__decrypt_payload_chunk(resp['payloads'][0])
 226             if data['success'] is True:
 227                 return data['result']['licenses'][0]['data']
 228             else:
 229                 self.kodi_helper.log(msg='Error getting license: ' + json.dumps(data))
 230                 return False
 231
 232     def __decrypt_payload_chunk(self, payloadchunk):
 233         payloadchunk = json.JSONDecoder().decode(payloadchunk)
 234         encryption_envelope = json.JSONDecoder().decode(base64.standard_b64decode(payloadchunk['payload']))
 235         # Decrypt the text
 236         cipher = AES.new(self.encryption_key, AES.MODE_CBC, base64.standard_b64decode(encryption_envelope['iv']))
 237         plaintext = cipher.decrypt(base64.standard_b64decode(encryption_envelope['ciphertext']))
 238         # unpad the plaintext
 239         plaintext = json.JSONDecoder().decode(Padding.unpad(plaintext, 16))
 240         data = plaintext['data']
 241
 242         # uncompress data if compressed
 243         if plaintext['compressionalgo'] == 'GZIP':
 244             data = zlib.decompress(base64.standard_b64decode(data), 16 + zlib.MAX_WBITS)
 245         else:
 246             data = base64.standard_b64decode(data)
 247
 248         data = json.JSONDecoder().decode(data)[1]['payload']['data']
 249         data = base64.standard_b64decode(data)
 250         return json.JSONDecoder().decode(data)
 251
 252
 253     def __tranform_to_dash(self, manifest):
 254
 255         self.save_file(self.kodi_helper.msl_data_path, 'manifest.json', json.dumps(manifest))
 256         manifest = manifest['result']['viewables'][0]
 257
 258         self.last_playback_context = manifest['playbackContextId']
 259         self.last_drm_context = manifest['drmContextId']
 260
 261         #Check for pssh
 262         pssh = ''
 263         if 'psshb64' in manifest:
 264             if len(manifest['psshb64']) >= 1:
 265                 pssh = manifest['psshb64'][0]
 266
 267         seconds = manifest['runtime']/1000
 268         init_length = seconds / 2 * 12 + 20*1000
 269         duration = "PT"+str(seconds)+".00S"
 270
 271         root = ET.Element('MPD')
 272         root.attrib['xmlns'] = 'urn:mpeg:dash:schema:mpd:2011'
 273         root.attrib['xmlns:cenc'] = 'urn:mpeg:cenc:2013'
 274         root.attrib['mediaPresentationDuration'] = duration
 275
 276         period = ET.SubElement(root, 'Period', start='PT0S', duration=duration)
 277
 278         # One Adaption Set for Video
 279         for video_track in manifest['videoTracks']:
 280             video_adaption_set = ET.SubElement(period, 'AdaptationSet', mimeType='video/mp4', contentType="video")
 281             # Content Protection
 282             protection = ET.SubElement(video_adaption_set, 'ContentProtection',
 283                           schemeIdUri='urn:uuid:EDEF8BA9-79D6-4ACE-A3C8-27DCD51D21ED')
 284             if pssh is not '':
 285                 ET.SubElement(protection, 'cenc:pssh').text = pssh
 286
 287             for downloadable in video_track['downloadables']:
 288
 289                 codec = 'h264'
 290                 if 'hevc' in downloadable['contentProfile']:
 291                     codec = 'hevc'
 292
 293                 hdcp_versions = '0.0'
 294                 for hdcp in downloadable['hdcpVersions']:
 295                     if hdcp != 'none':
 296                         hdcp_versions = hdcp
 297
 298                 rep = ET.SubElement(video_adaption_set, 'Representation',
 299                                     width=str(downloadable['width']),
 300                                     height=str(downloadable['height']),
 301                                     bandwidth=str(downloadable['bitrate']*1024),
 302                                     hdcp=hdcp_versions,
 303                                     nflxContentProfile=str(downloadable['contentProfile']),
 304                                     codecs=codec,
 305                                     mimeType='video/mp4')
 306
 307                 #BaseURL
 308                 ET.SubElement(rep, 'BaseURL').text = self.__get_base_url(downloadable['urls'])
 309                 # Init an Segment block
 310                 segment_base = ET.SubElement(rep, 'SegmentBase', indexRange="0-"+str(init_length), indexRangeExact="true")
 311                 ET.SubElement(segment_base, 'Initialization', range='0-'+str(init_length))
 312
 313
 314
 315         # Multiple Adaption Set for audio
 316         for audio_track in manifest['audioTracks']:
 317             audio_adaption_set = ET.SubElement(period, 'AdaptationSet',
 318                                                lang=audio_track['bcp47'],
 319                                                contentType='audio',
 320                                                mimeType='audio/mp4')
 321             for downloadable in audio_track['downloadables']:
 322                 codec = 'aac'
 323                 print downloadable
 324                 if downloadable['contentProfile'] == 'ddplus-2.0-dash' or downloadable['contentProfile'] == 'ddplus-5.1-dash':
 325                     codec = 'ec-3'
 326                 print "codec is: " + codec
 327                 rep = ET.SubElement(audio_adaption_set, 'Representation',
 328                                     codecs=codec,
 329                                     bandwidth=str(downloadable['bitrate']*1024),
 330                                     mimeType='audio/mp4')
 331
 332                 #AudioChannel Config
 333                 ET.SubElement(rep, 'AudioChannelConfiguration',
 334                               schemeIdUri='urn:mpeg:dash:23003:3:audio_channel_configuration:2011',
 335                               value=str(audio_track['channelsCount']))
 336
 337                 #BaseURL
 338                 ET.SubElement(rep, 'BaseURL').text = self.__get_base_url(downloadable['urls'])
 339                 # Index range
 340                 segment_base = ET.SubElement(rep, 'SegmentBase', indexRange="0-"+str(init_length), indexRangeExact="true")
 341                 ET.SubElement(segment_base, 'Initialization', range='0-'+str(init_length))
 342
 343
 344         xml = ET.tostring(root, encoding='utf-8', method='xml')
 345         xml = xml.replace('\n', '').replace('\r', '')
 346         return xml
 347
 348     def __get_base_url(self, urls):
 349         for key in urls:
 350             return urls[key]
 351
 352     def __parse_chunked_msl_response(self, message):
 353         i = 0
 354         opencount = 0
 355         closecount = 0
 356         header = ""
 357         payloads = []
 358         old_end = 0
 359
 360         while i < len(message):
 361             if message[i] == '{':
 362                 opencount = opencount + 1
 363             if message[i] == '}':
 364                 closecount = closecount + 1
 365             if opencount == closecount:
 366                 if header == "":
 367                     header = message[:i]
 368                     old_end = i + 1
 369                 else:
 370                     payloads.append(message[old_end:i + 1])
 371             i += 1
 372
 373         return {
 374             'header': header,
 375             'payloads': payloads
 376         }
 377
 378     def __generate_msl_request_data(self, data):
 379         header_encryption_envelope = self.__encrypt(self.__generate_msl_header())
 380         header = {
 381             'headerdata': base64.standard_b64encode(header_encryption_envelope),
 382             'signature': self.__sign(header_encryption_envelope),
 383             'mastertoken': self.mastertoken,
 384         }
 385
 386         # Serialize the given Data
 387         serialized_data = json.dumps(data)
 388         serialized_data = serialized_data.replace('"', '\\"')
 389         serialized_data = '[{},{"headers":{},"path":"/cbp/cadmium-13","payload":{"data":"' + serialized_data + '"},"query":""}]\n'
 390
 391         compressed_data = self.__compress_data(serialized_data)
 392
 393         # Create FIRST Payload Chunks
 394         first_payload = {
 395             "messageid": self.current_message_id,
 396             "data": compressed_data,
 397             "compressionalgo": "GZIP",
 398             "sequencenumber": 1,
 399             "endofmsg": True
 400         }
 401         first_payload_encryption_envelope = self.__encrypt(json.dumps(first_payload))
 402         first_payload_chunk = {
 403             'payload': base64.standard_b64encode(first_payload_encryption_envelope),
 404             'signature': self.__sign(first_payload_encryption_envelope),
 405         }
 406
 407         request_data = json.dumps(header) + json.dumps(first_payload_chunk)
 408         return request_data
 409
 410
 411
 412     def __compress_data(self, data):
 413         # GZIP THE DATA
 414         out = StringIO()
 415         with gzip.GzipFile(fileobj=out, mode="w") as f:
 416             f.write(data)
 417         return base64.standard_b64encode(out.getvalue())
 418
 419
 420     def __generate_msl_header(self, is_handshake=False, is_key_request=False, compressionalgo="GZIP", encrypt=True):
 421         """
 422         Function that generates a MSL header dict
 423         :return: The base64 encoded JSON String of the header
 424         """
 425         self.current_message_id = self.rndm.randint(0, pow(2, 52))
 426
 427         header_data = {
 428             'sender': self.esn,
 429             'handshake': is_handshake,
 430             'nonreplayable': False,
 431             'capabilities': {
 432                 'languages': ["en-US"],
 433                 'compressionalgos': []
 434             },
 435             'recipient': 'Netflix',
 436             'renewable': True,
 437             'messageid': self.current_message_id,
 438             'timestamp': 1467733923
 439         }
 440
 441         # Add compression algo if not empty
 442         if compressionalgo is not "":
 443             header_data['capabilities']['compressionalgos'].append(compressionalgo)
 444
 445         # If this is a keyrequest act diffrent then other requests
 446         if is_key_request:
 447             public_key = base64.standard_b64encode(self.rsa_key.publickey().exportKey(format='DER'))
 448             header_data['keyrequestdata'] = [{
 449                 'scheme': 'ASYMMETRIC_WRAPPED',
 450                 'keydata': {
 451                     'publickey': public_key,
 452                     'mechanism': 'JWK_RSA',
 453                     'keypairid': 'superKeyPair'
 454                 }
 455             }]
 456         else:
 457             if 'usertoken' in self.tokens:
 458                 pass
 459             else:
 460                 account = self.kodi_helper.get_credentials()
 461                 # Auth via email and password
 462                 header_data['userauthdata'] = {
 463                     'scheme': 'EMAIL_PASSWORD',
 464                     'authdata': {
 465                         'email': account['email'],
 466                         'password': account['password']
 467                     }
 468                 }
 469
 470         return json.dumps(header_data)
 471
 472
 473
 474     def __encrypt(self, plaintext):
 475         """
 476         Encrypt the given Plaintext with the encryption key
 477         :param plaintext:
 478         :return: Serialized JSON String of the encryption Envelope
 479         """
 480         iv = get_random_bytes(16)
 481         encryption_envelope = {
 482             'ciphertext': '',
 483             'keyid': self.esn + '_' + str(self.sequence_number),
 484             'sha256': 'AA==',
 485             'iv': base64.standard_b64encode(iv)
 486         }
 487         # Padd the plaintext
 488         plaintext = Padding.pad(plaintext, 16)
 489         # Encrypt the text
 490         cipher = AES.new(self.encryption_key, AES.MODE_CBC, iv)
 491         ciphertext = cipher.encrypt(plaintext)
 492         encryption_envelope['ciphertext'] = base64.standard_b64encode(ciphertext)
 493         return json.dumps(encryption_envelope)
 494
 495
 496     def __sign(self, text):
 497         """
 498         Calculates the HMAC signature for the given text with the current sign key and SHA256
 499         :param text:
 500         :return: Base64 encoded signature
 501         """
 502         signature = HMAC.new(self.sign_key, text, SHA256).digest()
 503         return base64.standard_b64encode(signature)
 504
 505
 506     def __perform_key_handshake(self):
 507         header = self.__generate_msl_header(is_key_request=True, is_handshake=True, compressionalgo="", encrypt=False)
 508         request = {
 509             'entityauthdata': {
 510                 'scheme': 'NONE',
 511                 'authdata': {
 512                     'identity': self.esn
 513                 }
 514             },
 515             'headerdata': base64.standard_b64encode(header),
 516             'signature': '',
 517         }
 518         self.kodi_helper.log(msg='Key Handshake Request:')
 519         self.kodi_helper.log(msg=json.dumps(request))
 520
 521         resp = self.session.post(self.endpoints['manifest'], json.dumps(request, sort_keys=True))
 522         if resp.status_code == 200:
 523             resp = resp.json()
 524             if 'errordata' in resp:
 525                 self.kodi_helper.log(msg='Key Exchange failed')
 526                 self.kodi_helper.log(msg=base64.standard_b64decode(resp['errordata']))
 527                 return False
 528             self.__parse_crypto_keys(json.JSONDecoder().decode(base64.standard_b64decode(resp['headerdata'])))
 529         else:
 530             self.kodi_helper.log(msg='Key Exchange failed')
 531             self.kodi_helper.log(msg=resp.text)
 532
 533     def __parse_crypto_keys(self, headerdata):
 534         self.__set_master_token(headerdata['keyresponsedata']['mastertoken'])
 535         # Init Decryption
 536         encrypted_encryption_key = base64.standard_b64decode(headerdata['keyresponsedata']['keydata']['encryptionkey'])
 537         encrypted_sign_key = base64.standard_b64decode(headerdata['keyresponsedata']['keydata']['hmackey'])
 538         cipher_rsa = PKCS1_OAEP.new(self.rsa_key)
 539
 540         # Decrypt encryption key
 541         encryption_key_data = json.JSONDecoder().decode(cipher_rsa.decrypt(encrypted_encryption_key))
 542         self.encryption_key = base64key_decode(encryption_key_data['k'])
 543
 544         # Decrypt sign key
 545         sign_key_data = json.JSONDecoder().decode(cipher_rsa.decrypt(encrypted_sign_key))
 546         self.sign_key = base64key_decode(sign_key_data['k'])
 547
 548         self.__save_msl_data()
 549         self.handshake_performed = True
 550
 551     def __load_msl_data(self):
 552         msl_data = json.JSONDecoder().decode(self.load_file(self.kodi_helper.msl_data_path, 'msl_data.json'))
 553         self.__set_master_token(msl_data['tokens']['mastertoken'])
 554         self.encryption_key = base64.standard_b64decode(msl_data['encryption_key'])
 555         self.sign_key = base64.standard_b64decode(msl_data['sign_key'])
 556
 557     def __save_msl_data(self):
 558         """
 559         Saves the keys and tokens in json file
 560         :return:
 561         """
 562         data = {
 563             "encryption_key": base64.standard_b64encode(self.encryption_key),
 564             'sign_key': base64.standard_b64encode(self.sign_key),
 565             'tokens': {
 566                 'mastertoken': self.mastertoken
 567             }
 568         }
 569         serialized_data = json.JSONEncoder().encode(data)
 570         self.save_file(self.kodi_helper.msl_data_path, 'msl_data.json', serialized_data)
 571
 572     def __set_master_token(self, master_token):
 573         self.mastertoken = master_token
 574         self.sequence_number = json.JSONDecoder().decode(base64.standard_b64decode(master_token['tokendata']))['sequencenumber']
 575
 576     def __load_rsa_keys(self):
 577         loaded_key = self.load_file(self.kodi_helper.msl_data_path, 'rsa_key.bin')
 578         self.rsa_key = RSA.importKey(loaded_key)
 579
 580     def __save_rsa_keys(self):
 581         self.kodi_helper.log(msg='Save RSA Keys')
 582         # Get the DER Base64 of the keys
 583         encrypted_key = self.rsa_key.exportKey()
 584         self.save_file(self.kodi_helper.msl_data_path, 'rsa_key.bin', encrypted_key)
 585
 586     @staticmethod
 587     def file_exists(msl_data_path, filename):
 588         """
 589         Checks if a given file exists
 590         :param filename: The filename
 591         :return: True if so
 592         """
 593         return os.path.isfile(msl_data_path + filename)
 594
 595     @staticmethod
 596     def save_file(msl_data_path, filename, content):
 597         """
 598         Saves the given content under given filename
 599         :param filename: The filename
 600         :param content: The content of the file
 601         """
 602         with open(msl_data_path + filename, 'w') as file_:
 603             file_.write(content)
 604             file_.flush()
 605
 606     @staticmethod
 607     def load_file(msl_data_path, filename):
 608         """
 609         Loads the content of a given filename
 610         :param filename: The file to load
 611         :return: The content of the file
 612         """
 613         with open(msl_data_path + filename) as file_:
 614             file_content = file_.read()
 615         return file_content