Partial encryption of JPEG2000 images based on EBCOT

Image encryption is vital to ensure confidential transmission and storage of images over Internet. However, real-time image encryption is still a challenge due to large amounts of data involved. As such, we propose a novel partial encryption of JPEG2000 images coded with EBCOT (embedded block coding with optimized truncation). We classify EBCOT codes into five categories, analyze effects of each type of data on image reconstruction, and then select two types of significant data to encrypt using a stream cipher. The results of computer simulations and security analyses demonstrate that the proposed method can achieve high security by encrypting about 3% data of the whole EBCOT bit-streams, while the compression rate is kept unchanged.