Image Compression-Encryption Scheme Based on 2D DWT, SPIHT and Qi Hyper-chaos

With an ever increase usage of multi-media content, such audio, image and video across networks, image compression and security of content has become almost a need to users who would want to transmit over such networks. Transmitting over such networks, especially with images, may result in some information in an image being lost. For that reason good and efficient encryption methods are needed to store and transmit images while preserving the best imaginable quality features enhanced with security. This paper suggests or develops an efficient image compression-encryption scheme based on Discrete wavelet decomposition, SPIHT and Qi hyperchaos. Pseudo-random numbers generated from Qi hyper chaos and which are in line with the Federal Information Processing Standards (FIPS) and National Institute of Standards and Technology (NIST) were used in this study. The random numbers were used to change the image characteristics and in essence to hide the visual information related to image. To achieve the selective Compression-encryption, the 2-D wavelet transform was used to decompose the image into details and approximation components, Set Partitioning in Hierarchical Tree compression method was used to compress the decomposed LL2 image before being encrypted with the bits stream key generated from the Qi hyper-chaos using exclusive or operation. The experimental results demonstrate that the proposed scheme is good for data compression and encryption.