A method for generating a security element with hidden coded information in a graphical image, security element and method for verification

摘要

The invention relates to a method for generating a security element with concealed coded information in a graphic illustration (1 '), such a security element and a method for verifying such a security element. The method for generating a security element comprising the steps. Providing a graphic two-dimensional image (1); Providing the information (31) to be encoded; Performing wavelet decomposition transforms to successively decompose the image into sub-maps corresponding to frequency bands (2-15, 21-25, 41-44); wherein the sub-maps are derived from the transform coefficients; Modifying individual transform coefficients of a selected one of the sub-maps (25) to insert the information to be encoded into the one selected sub-map (25); Performing inverse wavelet transforms to obtain a coded map (1 ') corresponding to the provided graphical map (1) in which the first information (31) is concealed, characterized in that, in successively performing the wavelet decomposition transformations, for generating the one submap (2-15, 21-25, 41-44) into which the information (31) is inserted, in addition to wavelet decomposition transformations with a first wavelet (a) at least one wavelet decomposition transform with one of the first wavelet different second wavelet (b) is executed.