function validateAuthentication(address _sender, uint _challenge, uint _partnerId) public constant returns (bool _isValid) {
      if (partnerMap[_partnerId][_sender].value == hydroPartnerMap[_partnerId][_sender].value
      && block.timestamp < hydroPartnerMap[_partnerId][_sender].timestamp
      && partnerMap[_partnerId][_sender].challenge == _challenge) {
          return true;
      }
      return false;
  }