基於位元平面層技術於灰階影像之階層式多重視覺秘密分享機制之研究與應用

A Study of Bit-level Processing Based on Gray-level Imagines of Hierarchical Multiple Visual Secret Sharing Schemes and Applications

廖惠雯 (H.W. Liao) 黃信維 (S.W. Huang) 、

黃志仁 (J.R. Huang) 、王培任 (P.R. Wang) 、陳立忠 (L.J. Chen)

嶺東科技大學資訊科技系

Department of Information Technology

Ling Tung University

摘 要

    視覺密碼學最早在 1994 年由 Naor 和 Shamir 所提出，灰階之階層式多重視覺秘密分享機制 利用傳統視覺密碼學及半色調處理技術，分享影像及還原後的機密影像之長與寬均擴展為原始影像之 2 倍，無法維持原本機密影像的大小，且產生影像失真的情況。本文 提出利用位元平面層技術應用於灰階之階層式多重視覺秘密分享機制，每一階層的成員仍擁有兩種機密影像，且灰階機密影像利用位元平面層技術分解及疊合替代傳統的半色調處理技術，再利用 Lukac 和 Plataniotis 所提出的解密規則，即可將分享影像恢復成原始機密影像，改善了失真及無法恢復原始機密影像之缺點。

 關鍵字： 視 覺密碼學、階層式多重視覺秘密分享機制、半色調處理技術、 位元平面層技術

Abstract

The concept of visual secret sharing scheme was first proposed by Naor and Shamir in 1994; the Gray-level images of hierarchical multiple visual secret sharing schemes were based on the traditional encryption and halftone processing technique; although they made stacks returned to the original secret images; however, the process made the original images distorted to 2×2 times their sizes.

This article utilized the Bit-level processing and applied it to the hierarchical multiple visual secret sharing schemes with each hierarchical affiliate having two sets of secret images; by applying the Bit-level decomposition / stacking and throug h simpl e logica l operation s was proposed by Lukac and Plataniotis , the process restored the original images to their sizes without distortion.

Thus when replacing the traditional halftone processing with Bit-level share technology, and applies it to the gray-level images will restore the share images to their original sizes.

 Keyword ： Visual Cryptography, Hierarchical Multiple Visual Secret Sharing Scheme, Halftone Technology, Bit-level Processing