Problems and prospects of secure data transmission in the automated process control system using Blowfish and "noise"

This article is devoted to the problems and prospects of secure data transmission in technological networks of the developed mobile complex for processing acid mine water (CPAMW). A variety of instruments and devices are used to extract a wide range of materials. For example, analog signals are measured with instrumentation and automation, digital signals (+24V) are used to control various shutoff valves and generate feedback (state of limit switches: open-closed, state of various nodes: on-off, state of technical protections: worked, did not work). To control the magnetizer, devices are used that generate PWM signals (pulse width modulation). All these appliances and devices are connected to controllers and servers via a technological network. The most commonly used RS-485 in conjunction with the open protocol ModBUS RTU / ASCII. This data transfer protocol does not use authorization and does not protect the transmitted data in any way (transmitted in clear form according to the protocol structure). The transmitted data alone does not contain classified information, but can be used to create emergencies at the CPAMW installation, up to the destruction of equipment and the threat to life and health of personnel.