Access control in cyber-physical systems using steganography and digital signatures

In a world in which technology has an essential role, security of the systems we use is a crucial aspect. Most of the time this means ensuring communications´ security, protecting data and it automatically makes us think of cryptography, changing the form of the data so no one can view it without authorization. Cyber-physical systems are more and more present in critical applications in which security is of the utmost importance. In the present paper, we propose a look on security not by encrypting data but by controlling the access to the system. For this we combine digital signatures with an encryption algorithm with divided private key in order to control access to the system and to define roles for each user. We also add steganography, to increase the level of security of the system.