#image steganography

Steganography is the technique of hiding information in other objects. Although many carrier objects can be used, digital images are the most popular because of their usage over the internet. For this purpose, many types of images steganographic techniques have been invented. Each of them has both pros and cons. It depends on the complexity, hiding capacity, security, and so on. In our research, we studied the two most popular techniques of image steganography, least significant bit LSB and chaotic logistic mapping to find the similarities, dissimilarities, and many other factors. In this paper, we presented a detailed comparison of the LSB and chaotic logistic mapping based image steganography for various carrier images and messages. 

Information hiding in a cover file is one of the most modernized and effective ways for transferring secret message from sender to receiver over the communication channel. There are many steganographic techniques for hiding secret message in image, text, audio, video and so on. Image Steganography is also one of the common methods used for hiding the information in the cover image. In this research work, the secret message is hidden in a cover image file using image steganography. LSB is very efficient algorithm used to embed the information in a cover file. The LSB based image steganography with various file sizes is analyzed and illustrated their results. Bitmap .bmp image is used as a cover image file to implement the proposed system. The detail Least Significant Bit LSB based image steganography is introduced. In this paper, the new embedding algorithm and extracting algorithm are presented. While embedding the secret message in a cover image file, the starting embedded pixel is chosen according to public shared key between sender and receiver. The original cover image and embedded image with secret message are analyzed with PSNR values and SNR values to achieve security. The resulting embedded image shows the acceptable PSNR and SNR values while comparing with the original cover image. The proposed system can help the information exchanging system over communication media. 

This work proposes a novel scheme for separable reversible data hiding in encrypted images. In the first phase, a content owner encrypts the original uncompressed image using an encryption key. Then, a data-hider may compress the least significant bits of the encrypted image using a data-hiding key to create a sparse space to accommodate some additional data. With an encrypted image containing additional data, if a receiver has the data-hiding key, can extract the additional data though the image content is not known. If the receiver has the encryption key, then can decrypt the received data to obtain an image similar to the original one, but cannot extract the additional data. If the receiver has both the data-hiding key and the encryption key, can extract the additional data and recover the original content without any error by exploiting the spatial correlation in natural image when the amount of additional data is not too large.