Side-channel attacks are a type of attack that involves the physical outputs of embedded devices while cryptographic operations are running on them to recover some secrets. In this work we refer to power analysis due to the exploitation of the power consumption. Studying it and using suitable techniques, it is possible to recover the secret key used for the encryption. The thesis aims to the comparison of the traces generated by an emulator and by a real device, evaluating if the emulator can be a valid alternative than the generation of real traces. The emulator is Rainbow while the real target is an ARM Cortex-M4 microcontroller with the help of NewAE Technology ChipWhisperer tool.