The integration of Multi-Processors System-on-Chip (MPSoCs) into the Internet -of -Things (IoT) context brings new opportunities, but also represent risks. Tight real-time constraints and security requirements should be considered simultaneously when designing MPSoCs. Network-on-Chip (NoCs) are specially critical when meeting these two conflicting characteristics. For instance the NoC design has a huge influence in the security of the system. A vital threat to system security are so-called side-channel attacks based on the NoC communication observations. To this end, we propose a NoC security mechanism suitable for hard real-time systems, in which schedulability is a vital design requirement. We present three contributions. First, we show the impact of the NoC routing in the security of the system. Second, we propose a packet route randomisation mechanism to increase NoC resilience against side-channel attacks. Third, using an evolutionary optimisation approach, we effectively apply route randomisation while controlling its impact on hard real-time performance guarantees. Extensive experimental evidence based on analytical and simulation models supports our findings
