Design and analysis of Compress-Encrypt-Stego technique for steganography

Preserving the secrecy of confidential information transmitted over a network has always been of utmost importance. Increasing use of data communication over networks also increases the need of security. Steganography is a technique that screens the existence of information by masking it behind some other seemingly innocuous media. But if the presence of information behind media is revealed by any method, the main purpose of steganography is violated. This paper proposes and analyzes a technique for steganography named Compress-Encrypt-Stego that pre-processes the text before hiding it behind a cover image. In pre-processing, the text is first compressed and then modified using a key. Processed text is then concealed behind cover image using transform domain based steganography. DCT is used to transform the cover image to frequency domain. The technique is implemented for various cover images and for different values of plain text and keys using MATLAB. The proposed technique is analyzed by varying the number of bits used to hide the data. This paper also discusses the security analysis of the proposed technique.