A Study Of Fault Analysis And Its Countermeasures

Currently, in the practical application fields, we usually use specialized hardware, software or firmware to realize cryptosystems, such as ASIC, FPGA, DSP or smart cards. During the running process, this kind of chip may leak some internal state information (such as execution time, power consumption, electromagnetic radiation and fault information). Therefore, the attacker could get the crucial information and discover keys. It is the side channel attack that was introduced in the case. Because of its wide and successful attack affects, the scholars at home and abroad have aroused great concerns on it; also it has become one of the most rapidly developing areas in Crypto-analysis. Side Channel Attacks could be divided into three branches: time analysis, power analysis and fault analysis. Among them, only fault analysis has the characteristic, which not only is via the hardware analysis, but via software simulation as well. It is more realistic than the other two branches. In the thesis, take the fault analysis as a clue, we will discuss on the attack and its countermeasures.We first use multi-factor analysis on fault attack. Then, we give a detailed fault analysis on both symmetric key and public key cryptography. Fault analysis countermeasures are summarized in three defensive categories: duplication-based, code-cased and randomization based countermeasures. Hardware redundancy and time redundancy are involved here. In a bird-eye view, Fault Analysis could defense through various specific algorithms. In SPN network we use formal methods to unify fault analysis and countermeasures. We proof a theorem on the code-based method: checking method of adding code in the input can not take the role in countermeasures. Randomization Thoughts are summed up from the system design to the defense of side channel attack. Random Thoughts are...