Dual lossless compression based image steganography for low data rate channels

Steganography is one of the most important fields of information security. Spatial domain 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 achieved. However, to transmit a secret message securely, final stego image is transmitted which is large in size than that of original secret message. And as result more data rate is required to transmit the secret message hidden in stego image. This work presents a new image steganography technique to increase the hiding efficiency and hence reduce the data rate required for transmitting the final stego file. The proposed technique uses lossless image compression technique to enhance data hiding capacity and apply compression before and after data hiding. In pre-compression, lossless compression technique is applied on secret message to reduce its size and in post-compression the stego image is subjected to lossless compression technique. A significant hiding capacity has been achieved with a reasonable high PSNR (i.e. greater than 30dB limit). The hiding efficiency is controlled by using different lossless compression technique, without the lost of secret information.