The success of Garbage-man-in-the-middle (GMITM) attack relies
on the possibility to access to the ”bin” of recipient in the cryptosystem. It is capable to recover the original plaintext by granting an entry to the ”bin”. There are basically two types of GMITM attacks, a polynomial attack and a homomorphic attacks. In this paper, an investigation was carried out to evaluate the polynomial structure of cryptosystem and the nature of a homomorphic attack on cryptosystem. The results show that the cryptanalyst could obtain the plaintext without knowing the secret number, a, b and R
