Due to the pervasiveness of microprocessors, security has become a very important matter. Breaching the security of a device used for sensitive applications, such as a smart card, has devastating effects, since all the devices of the same model will be affected. This thesis aims at showing how reverse engineering can lead to such a scenario, as it can grant an attacker with enough knowledge to carry out a dangerous exploit. In particular, this thesis describes the reverse engineering of a ROM of a highly secure chip. The final goal is to extract the ROM's content, a very common objective for an attacker.