The security of the IoT connected objects must be energy efficient. But most of the work around hardening by design show an additional cost, a multiplying factor of 2 to 5, on the surface, performance, power and energy, which does not meet the constraints of the IoT. Last 5 years research efforts on hardening have been guided by reducing silicon area or power, which do not always imply a decrease in energy, predominant criterion in autonomous connected objects. The postdoc topic addresses the hardening and energy consumption optimization of the implementation of security functions (attack detection sensors, cryptographic accelerator, random number generator, etc.) in 28nm FDSOI technology. From the selection of existing security bricks, unhardened in FPGA technology, the postdoc will explore hardening solutions at each step of the design flow in order to propose and to validate, into a silicon demonstrator, the most energy efficient countermeasures that guarantee a targeted security level. To achieve those goals, the postdoc can rely on existing methodologies of design and of security evaluation thanks to test benches and attack tools.