Abstract
This paper proposes an attack on a recently proposed cryptosystem using bilateral-diffusion algorithm with dynamical compound chaos. The original image encryption scheme employed a compound chaotic function and (linear feedback shift register) LFSR. Experimental results of the studied scheme showed that it is strong enough to resist against different attacks. The method used in the cryptosystem under study, presents weakness and a chosen plaintext attack can be done to recover the plain image without any knowledge of the key value. Only one pair of (plaintext/cipher text) is needed to totally break the cryptosystem.