數位時代的來臨，各種傳統的資料如書本、音樂和影像也都數位化，隨著網路技術快速發展，使得這些數位產品得以在網路上輕鬆的傳送，由於如此，也就衍生出網路安全的問題。 資料隱藏 ( Data Hiding ) 不同於所謂的加密 ( Encryption ) ，加密是將重要資料做轉換來提供安全性的技術，而資料隱藏是將重要資料嵌入在不受人注意的寄主媒介中，藉此分散敵人的注意來達到安全性。 本篇論文主要是針對在單色的數位影像上實做資料隱藏，我們提出一個高資料隱藏率的方法，讓我們修改些少的位元，就可以隱藏大量的資料在單色影像上。我們所提出的方法和以前的方法比較，能隱藏更多的資料並維持一定的影像品質和提供較高的安全性。 This paper studies how to hide/embed a piece of secret in a host message which is a binary image. An earlier paper [4] shows that as many as log2(mn+1) bits of secret data can be hidden in an arbitrary mn binary image block by modifying at most 2 bits in the block. In this paper, we improve that result by showing that as many as r≦ (log2(mn-1)」+ 2) bits can be hidden by modifying at most 3 bits in the block. Simulation and probabilistic analysis are presented, which verify that the new scheme does offer higher hiding capacity per altered bit. We also show how to extend the result for halftone images, which are a special type of binary images.
