Wavelets and Discrete Cosine Transform for Hidden Information into Images

In this work we perform some tests of steganography and watermarking on BMP format images. We use the Discrete Cosine Transform (DCT) and Wavelets in order to insert information on the high and medium frequencies. When steganography is used, we explain a method to introduce secret data in an image and we show the capacity of the image to accept this data. For the watermarking technique we indicate where the data should be placed in order to achieve a robust insertion of these data even on the presence of image compression. Finally, we make a comparison between theses two techniques.