text: #!/usr/bin/env python3
  # Copyright (c) 2019 The POSQ Core developers
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  '''
  Covers the 'Wrapped Serials Attack' scenario
  '''
  
  import random
  from time import sleep
  
  from test_framework.authproxy import JSONRPCException
  from test_framework.util import assert_equal, assert_greater_than
  
  from fake_stake.base_test import POSQ_FakeStakeTest
  
  class zPOSQwrappedSerialsTest(POSQ_FakeStakeTest):
  
      def run_test(self):
          q = 73829871667027927151400291810255409637272593023945445234219354687881008052707
          pow2 = 2**256
          self.description = "Covers the 'Wrapped Serials Attack' scenario."
          self.init_test()
  
          INITAL_MINED_BLOCKS = 351   # Blocks mined before minting
          MORE_MINED_BLOCKS = 31      # Blocks mined after minting (before spending)
          DENOM_TO_USE = 1000         # zc denomination used for double spending attack
          K_BITSIZE = 128             # bitsize of the range for random K
          NUM_OF_K = 5                # number of wrapping serials to try
  
          # 1) Start mining blocks
          self.log.info("Mining %d first blocks..." % INITAL_MINED_BLOCKS)
          self.node.generate(INITAL_MINED_BLOCKS)
          sleep(2)
  
          # 2) Mint zerocoins
          self.log.info("Minting %d-denom zPOSQs..." % DENOM_TO_USE)
          balance = self.node.getbalance("*", 100)
          assert_greater_than(balance, DENOM_TO_USE)
          total_mints = 0
          while balance > DENOM_TO_USE:
              try:
                  self.node.mintzerocoin(DENOM_TO_USE)
              except JSONRPCException:
                  break
              sleep(1)
              total_mints += 1
              self.node.generate(1)
              sleep(1)
              if total_mints % 5 == 0:
                  self.log.info("Minted %d coins" % total_mints)
              if total_mints >= 20:
                  break
              balance = self.node.getbalance("*", 100)
          sleep(2)
  
          # 3) Mine more blocks and collect the mint
          self.log.info("Mining %d more blocks..." % MORE_MINED_BLOCKS)
          self.node.generate(MORE_MINED_BLOCKS)
          sleep(2)
          mint = self.node.listmintedzerocoins(True, True)[0]
  
          # 4) Get the raw zerocoin data
          exported_zerocoins = self.node.exportzerocoins(False)
          zc = [x for x in exported_zerocoins if mint["serial hash"] == x["id"]]
          if len(zc) == 0:
              raise AssertionError("mint not found")
  
          # 5) Spend the minted coin (mine two more blocks)
          self.log.info("Spending the minted coin with serial %s and mining two more blocks..." % zc[0]["s"])
          txid = self.node.spendzerocoinmints([mint["serial hash"]])['txid']
          self.log.info("Spent on tx %s" % txid)
          self.node.generate(2)
          sleep(2)
  
          # 6) create the new serials
          new_serials = []
          for i in range(NUM_OF_K):
              K = random.getrandbits(K_BITSIZE)
              new_serials.append(hex(int(zc[0]["s"], 16) + K*q*pow2)[2:])
  
          randomness = zc[0]["r"]
          privkey = zc[0]["k"]
  
          # 7) Spend the new zerocoins
          for serial in new_serials:
              self.log.info("Spending the wrapping serial %s" % serial)
              tx = None
              try:
                  tx = self.node.spendrawzerocoin(serial, randomness, DENOM_TO_USE, privkey)
              except JSONRPCException as e:
                  exc_msg = str(e)
                  if exc_msg == "CoinSpend: failed check (-4)":
                      self.log.info("GOOD: Transaction did not verify")
                  else:
                      raise e
  
              if tx is not None:
                  self.log.warning("Tx is: %s" % tx)
                  raise AssertionError("TEST FAILED")
  
          self.log.info("%s PASSED" % self.__class__.__name__)
  
  
  
  if __name__ == '__main__':
      zPOSQwrappedSerialsTest().main()
  