Security analysis of shifted odd knapsack public key encryption scheme

We discuss on the securities of the two knapsack type public key cryptosystems, one proposed by Kasahara and Murakami(KM-PKC) using shifted-odd sequence and another proposed by Merkle and Hellman(MH-PKC) using super-increasing sequence. We apply Shamir's attack to KM-PKC. We compare the security of MH-PKC with that of KM-PKC from the standpoint of the efficiency when Shamir's attack is applied to them.