Selecting Plaintext in Rabin Cryptosystems Using Padding Generated by Pseudo-Random Bit Generators

The Rabin cryptosystem is an asymmetric cryptographic technique whose security, like that of RSA, is related to the difficulty of factorization. Rabin Cryptosystem was designed by Michael O Rabin in January 1979. In this asymmetric cryptosystem, recovering the plaintext from the ciphertext is difficult. This public key cryptosystem produces four plaintext messages during decryption. Rabin Cryptosystem is not widely used because of the difficulty in selecting a plaintext from the four ciphertexts. This paper proposes a solution to select a plaintext in Rabin Cryptosystems (Rabin, 1979) to add special structures or padding at the end of the plaintext to eliminate this problem. This paper proposes a number of techniques for generating pseudorandom bits to generate a padding for selecting one plaintext among the four. Efficiency of these techniques is explored by comparing their bit-generation speeds.