This paper describes a new countermeasure against side-channel power attacks. We show that a conventional chipcard can be powered using an organic electroluminescent diode (OLED) facing a photovoltaic cell. By doing so, the card’s power consumption becomes constant and equal to the OLED’s power consumption. Despite size, energy conversion and heat dissipation issues, we believe that this countermeasure nicely suits several high-security applications. Because photonic power firewalls guarantee physical isolation, we recommend photonic firewalls for applications where energy and form factor considerations are not as important as security ( e.g., diplomatic encryption devices).