Cryptanalysis of a New Knapsack Type Public-Key Cryptosystem

— Recently, Hwang et al. introduced a knapsack type public-key cryptosystem. They proposed a new algorithm called permutation combination algorithm. By exploiting this algorithm, they attempt to increase the density of knapsack to avoid the low-density attack. We show that this cryptosystem is not secure, as it based on basic Merkel-Hellman knapsack cryptosystem and because of the superincreasing structure, we can use shamir's attack on the basic Merkel-Hellman knapsack to break this cryptosystem.