使用CSS屬性設定之靜態網頁資訊隱藏技術

Abstract

網路與資訊科技的蓬勃發展，資訊傳送變得十分方便，然而在網路連結讓生活變得十分便利的同時卻也衍生出許多資安問題，例如：在傳送訊息時最擔心被有心人士擷取或被竄改。對機密資料進行加密並傳送雖然是個不錯的方式，但是卻也因為密文看起來雜亂無章反而更容易引起有心人士的關注。資訊隱藏技術是利用掩護媒體攜帶加密後的機密資訊至隱藏在影像裡的安全傳送機密技術。許多數位媒體都可被用來當作資訊隱藏時的負載媒體，最常見的是以數位影像為負載媒體。靜態網頁的組成是由許多標籤語言與風格設計的屬性調整合作，因此存在許多彈性設定空間，也是十分適合用來當作資訊隱藏的負載媒體。靜態網頁主要是透過HTML5與CSS的屬性設定達到豐富內容的網頁表現，我們利用網頁設計時的一些彈性設定作法來達到隱示機密資訊的目的。嚐試透過網頁中的色彩設定來進行資訊藏入，例如顏色的設定法就有rgb, hex, hsl與rgba等設定法而且使用不同設定法仍可以得到同樣的視覺效果。除此之外，我們亦可以透過修改色彩中的三原色值的LSB進一步多藏一些資料。經實驗測試，我們所提出的方法有效的將大量機密資訊藏入到網頁檔案之中，而且藏有機密資訊的網頁與原始網頁有著同樣的視覺品質。Because of the advanced development of networking and information technique, data delivery more convenient than before. However, some information security issues have been raised due to the wildly connected public computer networks. Such as, how to ensure that the integrity of secret message and secure delivered to the right receiver. To encrypt the message as cipher text is an excellent way to achieve the goal of secret data delivery but it will attractive unexpected user to pay extra attention on the cipher text. The reason is that the cipher text look like a meaningless random noise. Steganography is another way to securely deliver secret data. The main idea of Steganography is using digital multimedia to play the cover media for carrying the encrypted secret message. Here, the cover multimedia includes Image, Video, Audio, Text file, Program, and HTML file. The image is one of most popular digital media used to carry the secret message. A beautiful static webpage is composed by several mark language tags cooperating with the style settings. As we know, the usage of mark language tag is very flexible for arranging the look of webpage. We inspired from the tag and CSS attribute setting to design the data embedding rules to conceal secret data into the source code of static webpage. We try to modify the color setting to carry secret message. For example, the color setting has four ways namely rgb, hex, hsl, and rgba. All of those setting can generate the same effect of webpage view. Furthermore, the values in color setting can apply the LSB substitution to imply the secret data and increase the embedding payload. From the experimental results, the proposed method success achieves the goal of secret data delivery with large embedding payload.