Abstract: Here propose an efficient encryption then compression (ETC) system. The method composed of Encryption, Data hiding, Compression, Data extraction, Decompression and decryption. Encryption is done via prediction error clustering and random permutation. An adaptive histogram shifting (AHS) is used for data hiding. Wavelet compression is used to efficiently compress the encrypted image. An efficient histogram shifting method that modifies the pixel greyscale value within the range is proposed to embed data into the image and it provides good quality of marked images. Data hiding refers to hide data within a digital media. Media can be anything like audio, image and video. Hiding is done by modifying the contents of the digital media. Hiding process is done in such a way that modification of pixel values should be undetectable to the viewers. However, in various applications like military and medical applications, degradation of the over media is not allowed. So it is essential to introduce the data hiding in such a way that it is reversible and quality degradation after embedding is lowered.

Keywords: ETC, AHS, Data hiding, Data extraction.