A novel visual secret sharing scheme without image size expansion

Over the past few years, increasing concern about the privacy of information shared in computer systems has increased interest in data security. Visual cryptography is a secure secret sharing scheme that divides secret images into shares which on their own reveal no information of the original secret image. Recovery of the secret image can be performed by superimposing the shares. Hence, the process does not require any special software or hardware for cryptographic computations. However, loss of resolution and contrast, and also the image size expansion which results in the need for storage space, are resulting problems and have been the focus of many researchers. In this paper, we propose a novel visual secret sharing scheme without image size expansion. Compared to other schemes of visual cryptography, our perfectly secure scheme not only does not have pixel expansion, but also provides a high quality recovered image.