Visual cryptography: A brief survey

Abstract

Visual cryptography is an emerging technology to address the concerns regarding privacy of images. It is a powerful technique combining both the impeccable ciphers and secret sharing in cryptography with that of the raster graphics. Visual cryptography divides the secret image into shares or shadows during encryption. The term “visual” in visual cryptography stands for the fact that during decryption phase, a user can perceive the recovered secret with his/her visual system, without the intervention of machines. Various visual cryptography techniques have been discussed extensively in this survey. The metrics used to analyse the effectiveness of visual cryptography techniques have been briefed. The significant applications of visual cryptography have also been summarized in the survey.