  In our previous researches, a new digital watermarking scheme based on
chaotic iterations has been introduced. This scheme was both stego-secure and
topologically secure. The stego-security is to face an attacker in the
"watermark only attack" category, whereas the topological security concerns
other categories of attacks. Its Lyapunov exponent is evaluated here, to
quantify the chaos generated by this scheme.
  Keywords : Lyapunov exponent; Information hiding; Security; Chaotic
iterations; Digital Watermarking.
