Side-channel analysis has become an important research area since the publication of “Timing Attacks on Implementations of Diffie-Hellman, RSA, DSS, and Other Systems” by Kocher in 1996. From then on, one realized that not only the mathematical security of a cryptographic algorithm had to be ensured, but also the security of the implementation itself.
The electromagnetic side-channel, which originates from the varying currents inside the implementation, is the side-channel studied in this thesis. Although there are an increased number of degrees of freedom to measure the electromagnetic emission, the side-channel possesses certain properties that turn it into one that is more interesting than the traditional power consumption measurements. Among those properties, the ability to measure locally and in a contactless way make it very appealing for further research.
This doctoral thesis treats a large number of aspects in the domain of electromagnetic
Firstly, the feasibility of using electromagnetic measurements to perform side-channel attacks on FPGA implementations and a number of signal processing techniques to interpret the raw measurements, are studied. We also point out that
there exist methods to ensure consistent interpretation of the results.
Besides the signal processing side of electromagnetic analysis, we examine a more practical aspect as well. The measurement setup has a big impact on the effectiveness of the analysis and the measurement probe is one of the most important pieces of this setup. Therefore, we study a number of properties that define a probe’s suitability for electromagnetic analysis by means of case studies.
Finally, we take a look at countermeasures. We do not focus solely on the electromagnetic side-channel, but also and even mostly on the power consumption. Indeed, protection measures against power analysis are a subset of those against electromagnetic analysis.