Research On Side-channel Attacks Against Modular Exponetiation Algorithms In Public-key Cryptosystem

Recently,various by-pass information leakages are widely utilized to conduct sidechannel attacks and these attacks have become a serious threat to most cryptosystems.Chosen-message attack is a kind of passive attack by means of selecting special input messages.Combined attack is a compositive attacking method with more than one basic attacking models,this attack is more aggressive.This thesis firstly introduces another two practical chosen-messages 1 and N + 1 and utilize them to attack Boscher’s blind fault resistant exponentiation algorithm which used to be considered as an efficient side channel resistant exponentiation algorithm.In addition,This thesis show that Boscher’s algorithm is vulnerable to combined attack with combination of fault attack and simple power analysis attack.Furthermore,a countermeasure is proposed to resist the chosen-message attack over Boscher’s algorithm without nullifying its countermeasure features to DPA and DFA and a new countermeasure exponentiation algorithm is developed to resist the combined attack as well as chosen-message attack.The proposed algorithm can be employed to achieve an effective and security CRT-RSA implementation.To validate the proposed attack methods and countermeasures,The RSA coprocessors are designed to implement Boscher’s algorithm as well as the proposed countermeasure algorithms and launched the chosen-message attack and combined attack on them separately.The power leakage data is gathered via Modelsim and PrimeTime tools,the experiment results show that the proposed attacks are feasible and the defence countermeasures are efficient.