The problem of fault tolerance and fault resistance is becoming more and more important in all application fields. In this context, asynchronous designs provide inherent properties that make them attractive to design robust systems. Moreover, hardening techniques can be applied at the design time to improve their fault resistance with low area, speed and power costs. This work presents the latest characteristics analysis and conclusions on the potential of asynchronous circuits for both security and safety designs. It clearly demonstrates that the asynchronous technology enables the design of efficient fault tolerant/resistant integrated circuits.