Timing Resilience for Efficient and Secure Circuits

In this paper, we will cover several techniques that can enhance the resilience of timing of digital circuits. Using post-silicon tuning components, the clock arrival times at flip-flops can be modified after manufacturing to balance delays between flip-flops. The actual delay properties of flip-flops will be examined to exploit the natural flexibility of such components. Wave-pipelining paths spanning several flip-flop stages can be integrated into a synchronous design to improve the circuit performance and to reduce area. In addition, with this technique, it cannot be taken for granted anymore that all the combinational paths in a circuit work with respect to one clock period. Therefore, a netlist alone does not represent all the design information. This feature enables the potential to embed wave-pipelining paths into a circuit to increase the complexity of reverse engineering. In order to replicate a design, attackers therefore have to identify the locations of the wave-pipelining paths, in addition to the netlist extracted from reverse engineering. Therefore, the security of the circuit against counterfeiting can be improved.