Pixel Intensity Based High Capacity Data Embedding Method Mehdi Hussain Shaheed Zulfikar Ali Bhutto Institute of Science and Technology (SZABIST) Islamabad, Pakistan. mehdi141@hotmail.com Mureed Hussain Shaheed Zulfikar Ali Bhutto Institute of Science and Technology (SZABIST) Islamabad, Pakistan. mhussain@szabist-isb.edu.pk Abstract-- Steganography is the science of hiding a message signal to host signal, without any distortion in the hosted signal. Using steganography, information can be hidden in hosted carrier such as images, videos, sounds files, text files, and data transmission. In image steganography, to improve the capacity of hidden data into hosted image without causing any statistically significant modification has a major concern. Many novel data hiding method based on Least Significant Bits (LSB) and Pixel Value Differencing (PVD) to increase the hiding capacity have been proposed with imperceptible quality. In this paper we have improved the Modified Kekre’s Algorithm (MKA) which is based on LSB method. The improved scheme increases the embedding capacity while retaining the good quality of stego-image (carrying hidden data) as good as MKA. Experimental results show that the improved scheme outperform the original comparative scheme especially in capacity of hidden data-bits. Keywords- data hiding; high capacity embedding; variable least significant bits data embedding; I..INTRODUCTION Digital communication becomes more popular due to tremendous growth of internet. The security of such information is one of the major aspects of digital communications. Cryptography and steganography are well known and widely used techniques to secure information like, bank transaction, corporate communication, credit card, multimedia content copyrights and etc. Steganography derived from Greek, literally means “covered writing”. Steganography and cryptography are cousin in spy craft family, where cryptography scrambles the message which is unable to understand. Steganography hide the message into carrier, which is unable to seen [2]. In steganography, information can be hidden in hosted carrier such as images, videos, sounds files, text files, and data transmission. In this paper we are improving MKA (Modified Kekre’s Algorithm), where higher intensity of the pixel decide the number of bits to embed into the cover-image [1]. According to figures 2 and 3 lower intensity pixel does not distort the visual quality of pixel and it can also store higher number of bits. Our improved version shows that we are efficiently utilizing the maintain matrix (it maintain the position of pixel where 5 LSB are used to embed the data). The paper presents a review of image based steaganogrpahy techniques, its applications proposed so far in literature. We explain some efficient data hiding algorithm its advantages and disadvantages. In section II we explain some recent general high capacity data hiding schemes. In section III we describe our improved algorithm based on MKA [1]. In section IV present experimental results of comparison with MKA [1]. In section V include the conclusion and suggestions. A. Image Steganography In image steganography following terms are common. • Cover-Image: refers to the image used as the carrier to embed message into. • Message: refers to hide the data bits into cover-image. It can be plain text or some other image as a message. • Stego-Image: refers to the generated image, which is carrying a hidden message. • Stego-Key: refers to as password may used to hide and then later decode the message. In image steganography a process that hides the message into cover-image and generate a stego-image. That stego-image then sent to the receiver without anyone else knowing that it contain the hidden message. The receiver can extract the message with or without stego-key that depends on the hidden scheme [2]. figure 1 shows basic diagram of steganography. Generally image steganography algorithm classified into following different domains. • LSB: It is a simplest image based steganography where least significant bit of the image is used to embed and extract the hidden data bits. In [5] uses random LSB, and some certain block or area of the image used to hide the data. • DCT: Discrete cosines transform generally used in JPEG image compression. Simple embedding the data bits into the coefficients of the DCT [6], using LSB based method. DCT is mostly used in compressed type of images and its hiding capacity is less than uncompressed type of images. Further each domain of image steganography can be categorized into [3]. • High Capacity: Maximum size of information can be embedded into image. 978-1-4244-8003-6/10/$26.00 ©2010 IEEE