194 Int. J. Computational Science and Engineering, Vol. 7, No. 3, 2012 Copyright © 2012 Inderscience Enterprises Ltd. An image steganography for colour images using lossless compression technique P. Nithyanandam* Department of Computer Applications, SSN College of Engineering, Kanchipuram Dt, 603110, India E-mail: nithyanandamp@ssn.edu.in *Corresponding author T. Ravichandran Hindustan Institute of Technology, Coimbatore, 641032, India E-mail: dr.t.ravichandran@gmail.com E. Priyadharshini and N.M. Santron Department of Computer Applications, SSN College of Engineering, Kanchipuram Dt, 603110, India E-mail: indrapriyadharshini.e@gmail.com E-mail: nmsantron@gmail.com Abstract: Least significant bit (LSB) is a commonly used spatial domain technique which is classified into LSB replacement, LSB matching and matrix embedding. This paper models an algorithm which gives less distortion in cover image during embedding process. Peak signal to noise ratio (PSNR) is a familiar benchmark used in discriminating the quality of stego image over cover image. A Huffman encoded secret image bit stream is overlaid on the least significant bit of cover image through matrix embedding. As a result, the stego image is constructed with much less distortion when compared to the cover image ends up with higher PSNR value. A secret image which cannot be embedded in a normal LSB embedding technique can be overlaid in this proposed technique, since the secret image is Huffman encoded. Keywords: steganography; steganalysis; payload; stego image; least significant bit; LSB; bits per pixel; BPP; Huffman encoding; peak signal to noise ratio; PSNR; mean square error; MSE. Reference to this paper should be made as follows: Nithyanandam, P., Ravichandran, T., Priyadharshini, E. and Santron, N.M. (2012) ‘An image steganography for colour images using lossless compression technique’, Int. J. Computational Science and Engineering, Vol. 7, No. 3, pp.194–205. Biographical notes: P. Nithyanandam received his BE in Computer Science and Engineering from Madurai Kamaraj University, India in 2000. He received his ME in Computer Science and Engineering from BITS-Pilani in 2003. Currently, he is pursuing his PhD in Anna University. He is working as an Assistant Professor in SSN College of Engineering, Anna University, Chennai, India. His area of interest includes cryptography, image processing and information hiding. T. Ravichandran received his BE degree from Bharathiar University, India and ME degree from Madurai Kamaraj University, India in 1994 and 1997, respectively. He obtained his PhD in Computer Science and Engineering in 2007 from Periyar University, India. He is working as the Principal in Hindustan Institute of Technology, India. His research interests include theory and practical issues of building distributed systems, internet computing and security, mobile computing, performance evaluation, and fault tolerant computing. N.M. Santron received his BSc in Computer Science in 2009 from Bharathiar University, India. Currently, he is pursuing his MCA in SSN College of Engineering, Anna University, Chennai, India. His area of interest includes image processing and information hiding. E. Priyadharshini received her BCA in 2009 from Thiruvalluvar University, India. Currently, she is pursuing her MCA in SSN College of Engineering, Anna University, Chennai, India. Her area of interest includes image processing and information hiding.