Threshold Implementation as a Countermeasure against Power Analysis Attacks

One of the usual ways to find sensitive data or secret parameters of cryptographic devices is to use their physical leakages. Power analysis is one of the attacks which lay in such a model. In comparison with other types of side-channels, power analysis is so efficient and has a high success rate. So it is important to provide a countermeasure against it. Different types of countermeasures use different methods and can be applied at different levels. Masking is an effective one which provides provable security in algorithm level. however even masked algorithms are sometimes suspected to leak kind of information in a condition that implemented in hardware leads to power analysis attacks. Threshold implementation is a way to secure hardware implementations against such probable challenges. In this paper, first we will introduce the different attack models in block ciphers, then we will concentrate on the gray-box model and explain the concepts of power analysis attacks and fundamentals of masking countermeasure. Later we will discuss the challenges of masking method in hardware implementations and introduce threshold implementation and its different aspects.