A scalable encryption method allowing backward compatibility with JPEG2000 images

A new method for encryption of JPEG 2000 images, which is referred to as 'scalable encryption', is proposed in this paper. Scalable encryption method makes the encrypted images to have multi-level-encryption and to reduce the computational complexity of encryption, since different encryption algorithms can be simultaneously used in its procedure. Moreover, the encrypted images produced by the proposed method have the complete compliance with JPEG 2000, so that a standard JPEG 2000 decoder can decode the encrypted images and the useful functionalities of JPEG 2000 codestream are preserved after the encryption. For example, the proposed method enables that contents holders have no need of preparing two or more encrypted images for various users who are provided the different access rights. In addition to this, the time for the encryption can be controlled by selection of adequate encryption algorithms for faster processing.