Protection of JPEG compressed e-comics by selective encryption

Nowadays, there is an increasing number of digital comics, so-called e-comics, available on Internet. Protecting these ecomics without Digital Rights Management (DRM) is a new issue. In this paper, we propose a method to ensure the protection of e-comics by encrypting only bubbles so that the story will not be understandable. To develop this method, we used standards like JPEG compression and AES encryption. The first step of the method involves detecting bubbles, and we decided to use the MSER algorithm, which is the most commonly used for text detection. The second main step involves making these areas unreadable by encrypting AC coefficients of the JPEG block, corresponding to high frequencies during entropy coding. Several experimental results show the efficiency of the proposed method.