Pixel Value Difference Based Image Steganography with One Time Pad Encryption Pixel value differencing (PVD) and Least Significant Bit (LSB) embedding are well known spatial domain steganographic techniques. PVD utilizes the sharp changes of intensities among adjacent pixels where a large number of secret bits could be embedded without any perceptible change. onetime pad (OTP) symmetric cryptography is known for its security. In the proposed scheme one or more LSB bits of the selected pixels are used depending on the pixel intensity difference with neighboring pixels in 2 xc3x97 2 image blocks of the cover image. Secret bits are encrypted using OTP with randomly generated preshared key. Such encrypted bits are completely random and resemble noise hence make the scheme robust against different statistical attacks. Comparative simulations with some wellknown PVDbased techniques show good results in terms of visual imperceptibility and different quality metrics such as MSE, PSNR, SSIM etc.

Improvements on Data Insertion Technique in Encrypted Image against Lossy Compression This paper proposes two techniques in enhancing the robustness of a joint image encryption and data insertion method against lossy compression 1. Safety zone is first introduced to ensure that pixel values representing xe2x80x980xe2x80x99 are separated from those representing xe2x80x981xe2x80x99 with a gap in between. This empty gap serves as a buffer so that pixels from both groups do not cross and eventually affect the extraction process. Next, majority vote is also adopted so that error can be further suppressed, although reducing number of bits that can be inserted. Results suggest that both strategies can suppress error caused by lossy compression.