Image Encryption-Compression Using Combined Permutation and SPIHT Algorithm

Encryption-Compression techniques are recently used for the effective transmission of images. By choosing the encryption and compression technique effectively, the efficiency of the system can be increased. Here combined permutation is applied for encryption and SPIHT algorithm is used for compression. The intelligible information is present in an image due to the correlation of bit, block and pixel. If we decrease this correlation then it will be difficult to understand the content. Wavelet based image compression using SPIHT algorithm is efficient and computationally simple. Matlab R2013a is used for performing this task. Both PSNR value and compression ratio are calculated for two images named satellite. jpg and lena. jpg. Results indicate that for satellite. jpg CR is 9.4660 and PSNR is 36.17dB and for lena. jpg it is 26.22 and 36.76 respectively. The results are present and discussed in the paper.