New Product-Sum Type Public-Key Cryptosystems with Selectable Encryption Key Based on Chinese Remainder Theorem

摘要

Recently, Kasahara and Murakami proposed new product-sum typepublic-key cryptosystems with the Chi- nese remainder theorem,Methods B-II and B-IV. They also pro- posed a new technique ofselectable encryption key, which is re- ferred to as 'Home PageMethod (HP Method).' In this paper, first, we describe Methods B-IIand B-IV. Second, we propose an effective attack for Method B-II anddiscuss the security of Meth- ods B-II and B-IV. Third, applying theHP Method to Methods B-II and B-IV, we propose new product-sum typePKC with se- Lectable encryption key. Moreover, we discuss thesecurity of the Proposed cryptosystems.