A Session based Multiple Image Hiding Technique using DWT and DCT

This work proposes Steganographic technique for hiding multiple images in a color image based on DWT and DCT. The cover image is decomposed into three separate color planes namely R, G and B. Individual planes are decomposed into subbands using DWT. DCT is applied in HH component of each plane. Secret images are dispersed among the selected DCT coefficients using a pseudo random sequence and a Session key. Secret images are extracted using the session key and the size of the images from the planer decomposed stego image. In this approach the stego image generated is of acceptable level of imperceptibility and distortion compared to the cover image and the overall security is high.Comment: 4 pages,16 figures, "Published with International Journal of Computer Applications (IJCA)

High capacity steganographic method based upon JPEG

The two most important aspects of any image-based steganographic system are the quality of the stegoimage and the capacity of the cover image. This paper proposes a novel and high capacity steganographic approach based on Discrete Cosine Transformation (DCT) and JPEG compression. JPEG technique divides the input image into non-overlapping blocks of 8x8 pixels and uses the DCT transformation. However, our proposed method divides the cover image into nonoverlapping blocks of 16x16 pixels. For each quantized DCT block, the least two-significant bits (2-LSBs) of each middle frequency coefficient are modified to embed two secret bits. Our aim is to investigate the data hiding efficiency using larger blocks for JPEG compression. Our experiment result shows that the proposed approach can provide a higher information hiding capacity than Jpeg-Jsteg and Chang et al. methods based on the conventional blocks of 8x8 pixels. Furthermore, the produced stego-images are almost identical to the original cover images

A COMPARATIVE STUDY OF OBJECT ORIENTED STEGANOGRAPHIC TECHNIQUES

Steganography is defined as camoufling, secret information within other information i.e. hiding information. The steganography’s main objective is to communicate securely in such a manner that the true information/message is not visible to the intruder. Any unwanted parties should not be able to correlate any sense between cover image and stego image. Thus the stego image must be same as the original cover image. In this paper, a comparative study of steganographic methods that use skin tone detection is done. For comparison three methods are considered. At first steganography using DWT is discussed. It is done in frequency domain as we obtain more precise stego images. Here Haar transform is used which leads to four sub bands. The secret data is embedded into one of the high frequency sub band. In the second method, secret data is embedded within skin region of image that provides an excellent secure location for data hiding. Skin tone detection is performed using HSV and YCbCr color space models. The last implementation is performed by applying skin tone detection using YCbCr color space and the edge of those skin pixels is detected using canny edge detection filter and then the secret image is steganoflaged into cover image. Performances of the three techniques are compared based on the PSNR obtained