International Association for Cryptologic Research

International Association
for Cryptologic Research


Doo Ho Choi


Construction of efficient and secure Pairing Algorithm and its Application
Doo Ho Choi Dong-Guk Han Howon Kim
The randomized projective coordinate (RPC) method on pairing computing algorithm is a good solution which leads an efficient countermeasure against side channel attacks. In this paper, we investigate measures for the efficiency of the RPC based countermeasures of the pairing algorithm and construct a method that induce an efficient RPC based countermeasure against side channel attacks. As it application, we apply our construction method to the well-known $\eta_T$ pairing algorithm over binary fields and so we obtain an RPC based countermeasure of $\eta_T$ pairing which is more efficient than the RPC method on the original $\eta_T$ pairing algorithm.
New Signature Scheme Using Conjugacy Problem
We propose a new digital signature scheme based on a non-commutative group where the conjugacy search problem is hard and the conjugacy decision problem is feasible. We implement our signature scheme in the braid groups and prove that an existential forgery of the implementation under no message attack gives a solution to a variation of conjugacy search problem. Then we discuss performance of our scheme under suggested parameters.