Side-channel attacks are an increasingly important concern for the security of cryptographic embedded devices, such as the SIM cards used in mobile phones. Previous works have exhibited such attacks against implementations of the 2G GSM algorithms (COMP-128, A5). In this paper, we show that they remain an important issue for USIM cards implementing the AES-based MILENAGE algorithm used in 3G/4G communications. In particular, we analyze instances of cards from a variety of operators and manufacturers, and describe successful Differential Power Analysis attacks that recover encryption keys and other secrets (needed to clone the USIM cards) within a few minutes. Further, we discuss the impact of the operator-defined secret parameters in MILE-NAGE on the difficulty to perform Differential Power Analysis, and show that they do not improve implementation security. Our results back up the observation that physical security issues raise long-term challenges that should be solved early in the development of cryptographic implementations, with adequate countermeasures.

In the shadow-moiré system, the period of the grating is varied by rotation of the grating, so the phase of the moiré pattern is changed as well. By the selection of suitable rotation angles, three images at different positions of the grating are acquired to obtain the absolute distance from the object to the grating. A theoretical analysis is presented for the method, and some experiments have been done to verify the theoretical analysis. The results show that the method is fast and the accuracy is better than 10 μm. The measurable range is directly proportional to the period of the grating and inversely proportional to the angles at which the grating is rotated.

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