Ting-Ya Yang

An embedding strategy for large payload using convolutional embedding codes

A matrix embedding (ME) code is a commonly used steganographic technique that used linear block codes to perform the embedding process. However, a lack of low-complexity maximum-likelihood decoding schemes in linear block codes limited the embedding efficiency for sufficiently large lengths. This paper proposes a novel and practical hiding algorithm for binary data based on convolutional codes. Compared to a matrix embedding algorithm that uses linear block codes, the method proposed in this study is appropriate for embedding a sufficiently long message into a cover object. The proposed method employs the Viterbi decoding algorithm for embedding to identify the coset leader of convolutional codes for large payloads. Experimental results show that the embedding efficiency of the proposed scheme using convolutional codes is substantially superior to that of the scheme using linear block codes.

Low complexity PTS algorithms with error correction capability in OFDM systems

One of the challenging issues for orthogonal frequency division multiplexing (OFDM) system is high peak-to-average power ratio (PAPR) of the transmitted OFDM signals. Partial transmit sequence (PTS) technique can improve the PAPR statistics of an OFDM signal. However, the major drawback of the conventional PTS (C-PTS) is the high computational complexity. In this paper, we propose the parallel PTS (P-PTS)and serial PTS (S-PTS) methods to reduce the C-PTS complexity, based on the fact that the weighting factors are chosen as codewords of a linear block code. Compared to the C-PTS, the P-PTS and S-PTS methods not only reduce the computational complexity but also provide error correction capability for the weighting factors.

Matrix embedding in steganography with binary Reed–Muller codes

This study presents a modified majority-logic decoding algorithm of Reed-Muller (RM) codes for matrix embedding (ME) in steganography. An ME algorithm uses linear block code to improve the embedding efficiency in steganography. The optimal embedding algorithm in steganography is equivalent to the maximum likelihood decoding (MLD) algorithm in error-correcting codes. The main disadvantage of ME is that the equivalent MLD algorithm of lengthy embedding codes requires highly complex embedding. This study used RM codes to embed data in binary host images. The authors propose a novel low-complexity embedding algorithm that uses a modified majority-logic algorithm to decode RM codes, in which a message-passing algorithm (i.e. sum-product, min-sum, or bias propagation) is performed on the highest order of information bits in the RM codes. The experimental results indicate that integrating bias propagation into the proposed scheme achieves superior embedding efficiency (relative to when the sum-product or min-sum algorithm is used) and can even achieve the embedding bound of RM codes.

Modified Majority Logic Decoding of Reed-Muller Codes Using Factor Graphs

This study investigates the decoding algorithms of binary Reed-Muller (RM) codes. The main goal of the study is to modify majority-logic decoding using sum-product or min-sum decoding algorithms at the highest-order information bits in RM codes. Numerical results show that compared with the traditional majority-logic decoding algorithm, the modified majority-logic decoding method proposed in this study can reduce the bit error rate by a large margin. This is achieved without incurring a significant increase in decoding complexity because soft-decision decoding is only used in the highest information bits in RM codes whereas majority-logic decoding is still applied at the other orders of information bits in RM codes.

Generation of cyclically permutable codes by galois field Fourier transform

Cyclically permutable codes (CPCs) are important to communication networks, e.g., multiple access collision channels without feedback and frequency-hopping spread spectrum communication channels. A CPC is a block code of length n such that each codeword has full cyclic order n and all codewords are cyclically distinct. This study investigates the characteristics of finite fields to develop an efficient algorithm to find a CPC from a p-ary cyclic code, where p is a prime number. In this paper, the Galois field Fourier transform technique is used to generate a CPC of either primitive or non-primitive length.

Graph realization of reed-muller codes for data hiding

In recent years the information industry develops vigorously and the progress in technology results in thriving augmentation of internet and people pass messages mutually through network in large number and triggers the issue of information security. In order to protect the safety and reliability of message passing, the development of steganography is thereby generated. In this research we will aim at its embedding and the major point of investigation is how to ensure the quality of the host after embedding secret message that means how to lower its distortion. On the other hand we want to increase the embedding efficiency and in this way we can send much more messages. At the same time we also have to consider the problem of complexity as too complicated algorithm is not feasible. This thesis is data hiding of binary host image and the Reed-Muller Codes of linear block codes in the error-correcting codes is applied to conduct research on steganography. Decoding algorithm is presented to conduct simulation analysis and discussion aiming at the embedding rate and embedding efficiency.

Data Hiding Technique by Ternary Hamming Codes

A novel steganographic algorithm for ternay data based on ZZW construction over F_3 is proposed to improve the embedding efficiency. Contrast to the conventional ZZW construction using binary Hamming codes in the second channel, the proposed method employs ternary Hamming codes to embed the message at the second channel. For the first channel, a low rate convolutional codes is presented to enhance the embedding efficiency of this modified ZZW construction. The ZZW construction over F_3 provides excellent embedding efficiency for ternary signal, and can be greatly extended to embedding algorithm for non-binary steganography.