We present a known plaintext attack (KPA) on a recently proposed fully homomorphic cryptosystem (FHC). based on the problem of big integers factoring. We show that the considered FHC is insecure against KPA even if only one pair (plaintext. ciphertext) was intercepted by an adversary. https://www.roneverhart.com/Hosa-SH-8X4-25-Stage-Box-Non-locking-8x4-25-p37478/