Drinking fresh water, turning the lights on, travelling by tram, calling our family, or getting a medical treatment are usual activities, but the underlying SCADA (Supervisory Control and Data Acquisition) systems like CIS (Critical Infrastructure Systems), ICS (Industrial Control Systems) or DCS (Distributed Control Systems) were always the target of many types of attacks, endangered the above mentioned simple activities. During the last decades because of the fast spread of the internet based services and the continuous technical development these systems become more vulnerable than ever. Full reconstruction and innovative changes in older SCADA systems has high cost, and it is not always rewarding. Communication protocols as Modbus (1979) serve as a main basis for SCADA systems, so security of Modbus has a major impact of the security of SCADA systems. Our paper raises and answers questions about the security of the Modbus RTU protocol. We focus on the serial Modbus protocol, because in that method we found many unsolved problems, like lack of authentication of the participants, lack of secure channel and so on. The aim of this paper to propose a secure communication alternative for Modbus RTU @ RS485 wire. The main advantage of the proposed method is the coexistence with traditional slaves and bus systems and only software update is necessary

A key role in the development of smart Internet of Things (IoT) solutions is played by wireless communication technologies, especially LPWAN (Low-Power Wide-Area Network), which are becoming increasingly popular due to their advantages: long range, low power consumption and the ability to connect multiple edge devices. However, in addition to the advantages of communication and low power consumption, the security of transmitted data is also important. End devices very often have a small amount of memory, which makes it impossible to implement advanced cryptographic algorithms on them. The article analyzes the advantages and disadvantages of solutions based on LPWAN communication and reviews platforms for IoT device communication in the LoRaWAN (LoRa Wide Area Network) standard in terms of configuration complexity. It describes how to configure an experimental LPWAN system being built at the Department of Computer Science and Telecommunications at Poznan University of Technology for research related to smart buildings.

The paper presents analysis of the possibility of using selected hash functions submitted for the SHA-3 competition in the SDEx encryption method. The group of these functions will include the finalists of the SHA-3 competition, i.e. BLAKE, Grøstl, JH, Keccak, Skein. The aim of the analysis is to develop more secure and faster cryptographic algorithm compared to the current version of the SDEx method with SHA- 512 and the AES algorithm. When considering the speed of algorithms, mainly the software implementation will be taken into account, as it is the most commonly used.