International Association
for Cryptologic Research

Recent side-channel attacks on elliptic curve algorithms have shown that the security of these cryptosystems is a matter of serious concern.

The development of techniques in the area of Template Attacks makes it feasible to extract a 256-bit secret key with only 257 traces.

This paper enhances the applicability of this attack by exploiting both the horizontal leakage of the carry propagation during the finite field multiplication, and the vertical leakage of the input data. As a further contribution, our method provides detection and auto-correction of possible errors that may occur during the key recovery. These enhancements come at the cost of extra traces, while still providing a practical attack. Finally, we show that the elliptic curve technology developed in PolarSSL running on a ARM STM32F4 platform is completely vulnerable, when used without any modifications or countermeasures.