Consider an adversary which can look into a (boolean) circuit and runs an algorithm to make inferences about the signals carried by the components inside the circuit. These algorithms are called side-channel attacks. In this talk, we will see a theoretical model for these attacks and a scheme to protect the circuit against these attacks under the given model. This talk will be based on "Private circuits: Securing hardware against probing attacks" by Ishai, Sahai and Wagner in CRYPTO 2003, one of the first papers which introduced this problem.