Information hiding in gray scale images using pseudo-randomized visual cryptography algorithm for visual information security

Security has gained a lot of importance as information technology is widely used. Cryptography refers to the study of mathematical techniques and related aspects of Information Security like data confidentiality, data Integrity, and of data authentication. Visual cryptography (VC) is a process where a secret image is encrypted into shares which refuse to divulge information about the original secret image. Its strength is a fact that the decryption of the secret image is through human visual system without computation. A basic model for visual cryptography for natural images was proposed by Naor and Shamir. In this paper, a novel method of VC is presented for halftone images which represent the resultant image in the same size as the original secret image. Hiding of the visual information based on pseudo randomization and pixel reversal is also proposed.