  At ISCAS'2005, Yen et al. presented a new chaos-based cryptosystem for
multimedia transmission named "Multimedia Cryptography System" (MCS). No
cryptanalytic results have been reported so far. This paper presents a
differential attack to break MCS, which requires only seven chosen plaintexts.
The complexity of the attack is O(N), where $N$ is the size of plaintext.
Experimental results are also given to show the real performance of the
proposed attack.
