A NOVEL CRYPTOGRAPHIC TECHNIQUE THAT EMPHASIS VISUAL QUALITY AND EFFICIENY BY FLOYD STEINBERG ERROR DIFFUSION METHOD

Jainthi.K, Prabhu.P

Abstract: Visual cryptography is a cryptographic technique which allows visual information to be encrypted in such a way that decryption becomes a mechanical operation that does not require a computer. The original image can be split into shares, where unauthorized person cannot get the data which we hide within that share images. By stacking the two shares, the secret data can be revealed. The highlighted issue in VC is, the size and quality of the reconstructed image should be same as the original image. In this paper, a novel k out of k extended visual cryptography scheme (EVCS) is used, to improve security and to produce meaningful shares. Halftone visual cryptography (VC) encodes a secret image into k halftone meaningful image shares through Floyd Steinberg error diffusion algorithm. The algorithm achieves dithering using error diffusion, meaning it pushes (adds) the residual quantization error of a pixel onto its neighboring pixels, to be dealt with later. This algorithm takes a substantial time for encryption and decryption in a considerably calmer manner. Comparisons with previous approaches show the superior performance of the new method.

Keywords: k out of k, extended visual cryptography, halftone visual cryptography, Floyd Steinberg error diffusion algorithm.

DOI: https://doi.org/10.15623/ijret.2015.0402058