Each copy of a text document can be made different in a nearly invisible way by repositioning or modifying the appearance of different elements of text, i.e., lines, words, or characters. A unique copy can be registered with its recipient, so that subsequent unauthorized copies that are retrieved can be traced back to the original owner. In this paper we describe and compare several mechanisms for marking documents and several other mechanisms for decoding the marks after documents have been subjected to common types of distortion. The marks are intended to protect documents of limited value that are owned by individuals who would rather possess a legal than an illegal copy if they can be distinguished. We will describe attacks that remove the marks and countermeasures to those attacks. An architecture is described for distributing a large number of copies without burdening the publisher with creating and transmitting the unique documents. The architecture also allows the publisher to determine the identity of a recipient who has illegally redistributed the document, without compromising the privacy of individuals who are not operating illegally. Two experimental systems are described. One was used to distribute an issue of the IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, and the second was used to mark copies of company private memoranda.

Copyright protection for the electronic distribution of text documents : Identification and protection of multimedia information

An improved section-wise exploiting modification direction method

A novel data hiding method based on the least significant bit (LSB) substitution and the multi-pixel differencing (MPD) method is presented on the proposed method to improve the capacity of hidden secret data and to provide an imperceptible visual quality First, a sum of different values for a four-pixel sub-block is calculated The low value of the sum can be located on a smooth block and the high value is located on an edged block The secret data are hidden into the cover image by the LSB method in the smooth block, while the MPD method is concealed in the edged block The experimental results show that the proposed method has a higher capacity and maintains good visual quality

Image Data Hiding Method Based on Multi-Pixel Differencing and LSB Substitution Methods

This paper represents an improved data hiding scheme, CIE, which uses a codebook to improve the Exploiting Modification Direction (EMD) embedding scheme. In our scheme, one secret (2 n?+?x ???1)-ary digit is hidden in a group of pixels in an image as a modified secret digit. Our proposed scheme has an embedding rate $R=\log_2(2^{n+x}-1)/n$ , which is greater than the rate of the EMD scheme, which is R?=?log2(2n?+?1)/n for n???2 . Embedding rate R is the number of secret bits embedded in each cover pixel. Our experimental results demonstrate that our scheme is able to embed 3 times as many secret bits in an image compared to the original EMD embedding scheme when n?=?2 and x?=?5. Our scheme has low time complexity and achieves this higher embedding performance while retaining reasonable perceptual quality for the image. An experiment verifies these features of our proposed data hiding scheme.

Data hiding by an improved exploiting modification direction

The EMD method proposed by Zhang and Wang fully exploited modification directions. Modifications in different directions were used to represent different secret data. According to the experimental results, the highest capacity was demonstrated in the 5-ary notational system, where only one secret digit is embedded for each two pixels. But this is an inefficient method because it can be hidden more secret data without revealing to the human visual system. To improve an embedding capacity, Chang et al. proposed two-stage EMD method, Lee et al. restricted to 8-ary embedding for the EMD method, and also Lee et al. segmented the pair of cover data into two parts to embed higher secret data. But still have a room for hiding more secret data. This paper proposes an improved method of the EMD method to hide more secret data while maintaining a high PSNR value. The proposed method can embed secret bit on every pixel of cover data. The experimental results demonstrate that the proposed method has a high capacity and good visual quality.

Improved Exploiting Modification Direction Method by Modulus Operation

This study proposes a data hiding method based on run length encoding. This proposed method uses the location of accumulated run length values, where the cover data run length are compared with the secret data run length. The run length matching (RLM) method uses the run length table which is constructed from the cover and secret data. The experimental results demonstrated that the RLM has advantages with respect to different types of data and run length encoding value match.

The Hiding of Secret Data Using the Run Length Matching Method

X. Zhang and S. Wang proposed an Exploiting Modification Direction (EMD) method that fully exploits modification directions. Modifications in different directions were used to represent different secret data. In 5-ary notational system, only one secret digit is embedded for each two pixel. This paper proposes an improved method for EMD which can hide more secret data while maintaining a high PSNR value. The proposed method could embed on every pixel for cover data. The experimental results demonstrate that the proposed method has a high capacity and good quality.

Improved Data Hiding Method by Exploiting Modification Direction

This paper proposes a new method for data hiding in binary images using optimized bit position to replace a secret bit. This method manipulates blocks, which are subdivided. The parity bit for a specified block decides whether to change or not, to embed a secret bit. By finding the best position to insert a secret bit for each divided block, the image quality of the resulting stego-image can be improved, while maintaining low computational complexity. The experimental results show that the proposed method has an improvement with respect to a previous work.

Improved Data Hiding Method by Block Parity for Binary Images

Data hiding is one of protective methods that can authenticate the completeness of digital information and protect intelligent property rights and copyright through secret communications. In this paper, we propose a data hiding method using pixel-value modular operation that has a high capacity while maintaining a good visual quality. The proposed method can embed secret data on the every pixel of a cover image by modular operation. The experiment results demonstrate that the proposed method has a high capacity and good visual quality where the embedding capacity is 91,138 bytes, the PSNR is 47.94dB, and the Q index is 0.968.

Jin-Yong Byun

Papers

The Hiding of Secret Data Using the Run Length Matching Method

Improved Data Hiding Method by Exploiting Modification Direction

Improved Data Hiding Method by Block Parity for Binary Images

Data Hiding Using Pixel-Value Modular Operation

An efficient and secure steganography scheme suitable for m-commerce