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.

In recent years, due to the sophistication offered by the Internet, strategic organizations like nuclear power plants are linked to the outside world communication through the Internet. The entry of outside world communication into strategic organization (nuclear power plant) increases the hacker's attempts to crack its security and to trace any information which is being sent among the top level officials. Information security system in nuclear power plant is very crucial as even small loophole in the security system will lead to a major disaster. Recent cyber attacks in nuclear power plant provoked information security professionals to look deeply into the information security aspects of strategic organizations (nuclear power plant). In these lines, Shamir secret sharing scheme with dynamic access structure (SSSDAS) is proposed in the paper which provides enhanced security by providing dynamic access structure for each node in different hierarchies. The SSSDAS algorithm can be applied to any strategic organizations with hierarchical structures. In this paper the possible scenarios where SSSDAS algorithm can be applied to nuclear power plant is explained as a case study. The proposed SSSDAS scheme identifies the wrong shares, if any, used for reconstruction of the secret. The SSSDAS scheme also address the three major security parameters namely confidentiality, authentication and integrity.

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.