A new side channel attack against a simple LFSR is presented. The proposed attack targets a single Galois LFSR running on an embedded device where the only accessible information is the side channel leakage. Even if it is made only of simple XOR gates, such an object is vulnerable to side channel cryptanalysis depending on its implementation. Our attack combines simple side channel analysis and statistical analysis to guess output bits and fast correlation attack to recover the initial state. In practice, even if a LFSR is never used alone, this attack shows that simple XOR gates can reveal significant information in some circumstances.
['Antoine Joux', 'Pascal Delaunay']
Galois LFSR, Embedded Devices and Side Channel Weaknesses