Modelling and Analysis of Confluence Attack by Hardware Trojan in NoC

Over the years, system on chip (SoC) designs have evolved extensively sophisticated in order to fulfil the need of increasing complexity of running applications driven by the advancement of VLSI technology. The next generation multiprocessor system on chip (MPSoC) integrates hundreds of processing elements on a single chip, expected to achieve high performance, low latency, and low-power consumption. Tiled chip multicore processors (TCMP) with network on chip (NoC) have become a foundation for the computation critical embedded and real-time systems. Faster time-to-market restraint and business competition compelled manufacturers to look for the prospects of manufacturing SoCs integrated with various third party intellectual property (3PIP). Usage of 3PIP gave rise to exploit the underlying interconnect while adding some unwanted malicious circuit known as hardware trojan (HT), making NoC vulnerable to get attacked. A tiniest manipulation of any communication attribute by HT can degrade the overall behaviour of the system significantly while impacting NoC performance metrics. In this paper, we present one of such study considering HT malign behaviour of manipulating the output port of each incoming flit from specific ports once genuine route computation takes place and re-directs all to one port causing disruption in tile communication.The proposed HT is intermittent in nature and activates for few cycles. We study the behaviour of proposed confluence attack and analyze its impact over network level. The empirical evaluation exhibits the misbehaviour of the packet communication in terms of wrong usage of VCs and extra hop distance overhead. To validate the proposed work, various performance metrics like buffer utilization, virtual channel utilization, number of flits processed, link utilization, and the like are analyzed. We also show that such HTs are difficult to detect due to marginal increase at malicious port traffic leaving no trace of malicious conduct.