A Modification of the Rabin Cryptosystem Based on Cubic Residues

Abstract

In the Rabin cryptosystem there are four different decryption results for each ciphertext. Thus, extra complexity is required on decryption to identify which of the four possible decryption results is the true plaintext. We propose a modification of the Rabin cryptosystem based on cubic residues. Let p and q be primes, N  pq . The sender Bob computes ciphertext 3 c  m (mod N) to Alice, where m is a confidential message. Alice decrypts the ciphertext c by the proposed method in this paper and gets the only one plaintext m. The proposed cryptosystem is provably secure against a chosen plaintext attack if and only if the integer factorization problem is hard.