No abstract

Text Steganography uses text documents as cover medium to communicate the secret messages, covertly, by making unnoticeable distortions in the cover medium. Character-Level Embedding Technique (CLET), a variant of text steganography, embeds a secret character by serially marking/distorting an identical character in the cover medium. Hence, these techniques suffer from low embedding capacity as the occurrence of certain alphabets in a text document is not uniform/guaranteed. In addition, identification of the marked cover character itself can reveal the hidden secret. This makes the CLET a less preferable choice. To overcome the aforementioned shortcomings, this paper proposes a novel CLET by introducing the Frequency Normalization Set in combination with the Character and String Mapping. The combination allows a low occurring character to get embedded in several cover characters, and thereby boosts its embedding probability. In addition, the combination also ensures the uniform embedding probability of secret characters. A font attribute called the character spacing is used to embed the secret. Experiments were conducted to investigate the embedding capacity, uniformity in embedding probability and frequency profile of stego characters of the proposed method. A comparison of the proposed method with the existing CLET algorithms is also provided. Various applications and the security aspects of the proposed method have also been discussed.

Today even sensitive organizations like nuclear power plants are connected to the internet. As information security is of utmost priority to such organizations, achieving the same is a challenging task while using the public network like the internet. Though cryptography could be used to enhance the information security, it cannot hide its own presence from the attackers. This drawback lead security professionals to look for an alternate technique like steganography. Steganography hides the secret information, stealthily, inside another innocent looking cover medium like text, image, audio and video. Considering these, this paper proposes a novel text steganographic algorithm that embeds images as codes in the font attributes such as color, character spacing and kerning. The procedure of representing an image as codes makes the proposed method independent from the resolution of the image. Experiments were conducted by embedding diverse categories of images. A comparison with the best existing method depicted that the embedding capacity attained by the proposed method is higher at 1.59-bits/character, which suits best for low bandwidth environments. Various security aspects of the proposed method have also been discussed.