New power analysis on the Ha-Moon algorithm and the MIST algorithm

Abstract

Side channel attacks have been attracted by most implementers of cryptographic primitives. And Randomized Exponentiation Algorithm (REA) is believed to be a good countermeasure against them. This paper analyzes the security of the two well-known REAs, the Ha-Moon algorithm and the MIST algorithm. Finding the fact that the intermediate values are variable in two cases, this paper shows that Ha-Moon algorithm is not secure even when it deploys both randomized binary recording technique and branch removing technique for DPA and SPA, respectively. In addition, this paper analyzes the security of the MIST algorithm. Some adaptively chosen ciphertext attacker can lower the security deeply, which can be placed more below than Walter's analysis.