On the Security of the Yi-Tan-Siew Chaos-Based Cipher

This paper analyzes the security of the Yi-Tan-Siew chaos-based cipher proposed in [1]. It is found that the claimed key (α,β, γ,K) collapses to be (α, γ) under a differential chosen-plaintext attack, and that an intermediate variable (called noise vector) used in the encryption function does not have a uniform distribution, which will downgrade the security of the cipher. Also, analysis shows that the security of this cipher is independent of the use of the chaotic tent map, so that the proposed cipher literally does not provide useful experience on the design of the chaos-based ciphers.