Increasing Hiding Efficiency of Image Steganography using Pre and Post Image Compression

Abstract

Steganography is one of the important fied of information security. A steganography technique hides secret information in the least significant bits of cover image. Security of hidden information and hiding efficiency are two main objectives of a steganographic technique. High data hiding efficiency and good visual quality of stego image are always attempted to be achieves. The work presents a new image steganography technique to increase the hiding capacity and security of hidden information. It makes use of lossless image compression technique to enhance hiding capacity and applied compression before and after data hiding. In pre-compression,lossless compression is applied on secret message to reduce its size and in post-compression the stego image is subjected to lossless compression. The pre-compression increase the hiding efficiency of 4LSB steganography from 50% and a hiding efficiency of 89% has been achieved with LZW compression technique with a compression ratio of 0.56. The PSNR value greater than 30dB threshold is presented by the proposed method. A PSNR of up to 43dB has been achieved.