Publications

Abstract : The vector decomposition problem (VDP) is a computational problem on which security of many public key cryptosystems relies. Yoshida proposed VDP and also proved that VDP on two-dimensional vector space is at least as hard as the computational Diffie-Hellman Problem on its one-dimensional subspace. Okamoto and Takashima generalized VDP into higher dimensional vector spaces and provided a homomorphic encryption scheme. They also provided a protocol to securely evaluate a 2DNF formula. Partial password authentication is a novel method in financial cryptography, an authentication method which requires only arbitrary characters of the existing password. Using the homomorphic encryption scheme of Okamoto and Takashima, we propose a similar protocol to securely evaluate a 2DNF formula which provides partial password authentication. © International Science Press.