Novel Format-compliant Encryption for JPEG2000 Images

摘要

Based on scrambling and chaos, an encryption algorithm is proposed and embedded into the JPEG2000 compression. Firstly, it scrambles coefficient positions in low resolution and confuses their values. In the scrambling, data of LL band are used to disturb the chaos. Secondly, it takes diffusion and substitution for coefficients of low resolution. Thirdly, it changes the coefficient signs in the first wavelet decomposition. Lastly, it scrambles positions of all coefficient blocks of entropy coding within the same resolution. Theoretical analysis shows that the algorithm has huge key space to defend violent attack, affects the granularity of JPEG2000 code-stream slightly. Experiments show that the encryption algorithm achieves good visual effect, gets high security, takes low computational complexity, and affects compression performance to a small extent.