class Spotixor:
   TEST = [0x2560a948, 0x421bca8b, 0x98329c40, 0x45d33a95]
   # screenshot_example.png

   @ staticmethod
   def v28decode (key0, key1, data4):
      out = data4 [:]

      # git clone https://gitlab.com/fuck-capitalism/spotifykeydumper
      # Hooks.cpp keyToLE_hook_v28
      for index in range (15, -1, -1):
         left = out [(index - 1) & 3]
         out [index & 3] = (out [index & 3] + (((left + index + key0) & (left * 16 + key1)) * 2 - 17 * left - index - key1 - key0)) & 0xFFFFFFFF

      return out

   @ staticmethod
   def xordecode (key0, key1, data4):
      out = data4 [:]

      for index in range (15, -1, -1):
         left = out [(index - 1) & 3]
         a    = left + index + key0
         b    = (left << 4) + key1
         out [index & 3] = (out [index & 3] - (a ^ b)) & 0xFFFFFFFF

      return out

   @ staticmethod
   def xorencode (key0, key1, data4):
      out = data4 [:]

      for index in range (16):
         left = out [(index - 1) & 3]
         a    = left + index + key0
         b    = (left << 4) + key1
         out [index & 3] = (out [index & 3] + (a ^ b)) & 0xFFFFFFFF

      return out

   @ staticmethod
   def show (data):
      return ' '.join ("{:08x}".format (x) for x in data)


def work_spot ():
   key0 = 0xcafebabe
   key1 = 0xdeadbeef

   data = Spotixor.TEST
   print ("data", Spotixor.show (data))

   enco = Spotixor.xorencode (key0, key1, data)
   print ("enco", Spotixor.show (enco))

   deco = Spotixor.v28decode (key0, key1, enco)
   print ("deco", Spotixor.show (deco))

   dec2 = Spotixor.xordecode (key0, key1, enco)
   print ("dec2", Spotixor.show (dec2))