watermarking scheme based on multiple chaotic maps

a watermarking scheme for grayscale image isproposed based on a family of the chaotic maps and discretecosine transform. jacobian elliptic mapis employed to encrypt ofwatermarked logo. piecewise nonlinear chaotic map is also usedto determine the location of dct coefficients for the watermarkembedding. the purpose of this algorithm is to improve theshortcoming of watermarking such as small key space and lowsecurity. therefore the size of key space for initial conditions andcontrol parameters is computed about and this keyspace is large enough to resist the attacks. toevaluate therobustness and effectiveness of proposed method, several attacksare applied to the