Successful Attack on an FPGA-based Automatically Placed and Routed WDDL+ Crypto Processor

In this paper, we report the first successful attack on a DES crypto co-processor protected by the “Positive” Wave Dynamic Differential Logic (WDDL+) and embedded in a Field Programmable Gates Array (FPGA). This attack is unambiguous as the full key is retrieved. We experimentally show that this countermeasure resists to Differential Power Analysis (DPA), but can be broken by a totally non-invasive Electro-Magnetic Analysis (EMA) method. The method relies on two stages, the first being a localisation phase by means of cartography, and the second being the EMA attack on the most relevant area.