Abstract
This paper introduces a technique to localize data-dependent electromagnetic emanations among the overall circuit emanations. Locating areas characterized by data dependent EM emissions is particularly interesting to: (a) localize specific digital blocks such as cryptographic coprocessors among the noise emanations generated by the rest of the circuit, (b) to efficiently position small magnetic loops used to perform Differential or Correlation Electro-Magnetic Analyses (DEMA and CEMA).