# Module `onionr.onionrcrypto.cryptoutils.verifypow`

Source code

    from .. import hashers
    import config, onionrproofs, logger
    import onionrexceptions
    def verify_POW(blockContent):
        '''
            Verifies the proof of work associated with a block
        '''
        retData = False

        dataLen = len(blockContent)

        try:
            blockContent = blockContent.encode()
        except AttributeError:
            pass

        blockHash = hashers.sha3_hash(blockContent)
        try:
            blockHash = blockHash.decode() # bytes on some versions for some reason
        except AttributeError:
            pass

        difficulty = onionrproofs.getDifficultyForNewBlock(blockContent)

        if difficulty < int(config.get('general.minimum_block_pow')):
            difficulty = int(config.get('general.minimum_block_pow'))
        mainHash = '0000000000000000000000000000000000000000000000000000000000000000'#nacl.hash.blake2b(nacl.utils.random()).decode()
        puzzle = mainHash[:difficulty]

        if blockHash[:difficulty] == puzzle:
            # logger.debug('Validated block pow')
            retData = True
        else:
            logger.debug("Invalid token, bad proof")
            raise onionrexceptions.InvalidProof('Proof for %s needs to be %s' % (blockHash, puzzle))

        return retData

## Functions

`def verify_POW(blockContent)`

  Verifies the proof of work associated with a block

  Source code

      def verify_POW(blockContent):
          '''
              Verifies the proof of work associated with a block
          '''
          retData = False

          dataLen = len(blockContent)

          try:
              blockContent = blockContent.encode()
          except AttributeError:
              pass

          blockHash = hashers.sha3_hash(blockContent)
          try:
              blockHash = blockHash.decode() # bytes on some versions for some reason
          except AttributeError:
              pass

          difficulty = onionrproofs.getDifficultyForNewBlock(blockContent)

          if difficulty < int(config.get('general.minimum_block_pow')):
              difficulty = int(config.get('general.minimum_block_pow'))
          mainHash = '0000000000000000000000000000000000000000000000000000000000000000'#nacl.hash.blake2b(nacl.utils.random()).decode()
          puzzle = mainHash[:difficulty]

          if blockHash[:difficulty] == puzzle:
              # logger.debug('Validated block pow')
              retData = True
          else:
              logger.debug("Invalid token, bad proof")
              raise onionrexceptions.InvalidProof('Proof for %s needs to be %s' % (blockHash, puzzle))

          return retData