Novel authentication scheme with pseudorandom sequences in the frequency domain of images

In this paper, we introduce a novel message hiding scheme for the purpose of authentication inside images. The hiding process is performed by means of insertion in the frequency domain of Discrete Cosine Transform. By employing a type of sequences with well-defined, low cross-correlation values to encode information, we were able to embed messages inside images. Furthermore, it is also possible to verify the existence of hidden content, given knowledge of the correct sequences. To achieve a good balance between robustness and imperceptibility, the middle frequency region in Transform domain is selected. It is shown that, without knowing full parameters of sequences generation, it would be very difficult to extract what is hidden. The quality of resulting images seem to be similar to the original images; distortions are minimal as shown by their Peak Signal-to-Noise Ratio and Structural Similarity.