中文摘要：

现有的乘积码技术是基于特定奇偶校验矩阵H生成（n,k）线性分组码的,对2^r1-1×2^r2-1汉明码阵的1～2^r1-1行及1～2^r2-1列逐行逐列嵌入密文比特.乘积码是一种利用短码构造长码的并行级联分组码,译码采用相对简单的迭代译码技术.提出一种基于嵌入列扩展的±1改进乘积隐写码（plus-minus one modified product steganographic coding,±1 MPSC）.与原有的完美乘积码（product perfect code,PPC）相比,增加了2^r2-1-1个嵌入列.此外,还提出一种新的嵌入技术,利用最低有效位及次低有效位建立异或数据链以降低反转次数,提高嵌入效率.理论分析与实验结果表明,该方法的嵌入率比原有的PPC算法提升近1.33倍,D-E曲线总体性能提升接近2%.

英文摘要：

In the existing product coding technique,secret data are embedded into rows and columns of a particular Hamming code matrix in a sequential fashion using the（n,k） linear block codes generated with a parity-check matrix H.The product code is a type of parallel concatenated block code that uses short codes to construct a long code.In decoding,a relatively simple iterative technique is used.This paper proposes a novel algorithm of ±1 modified product steganographic code（±1 MPSC） by expending some embeddable columns.Compared with the product perfect code（PPC）,±1 MPSC uses2^c-1-1 additional columns where c is the column number of the Hamming code matrix.It also uses a XOR data list constructed by LSB and second LSB of adjacent carrier elements to further reduce the number of flips to improve embedding efficiency.The theoretical analysis and experiments show that the embedding rate of the proposed method reaches1.33 times that of PPC,and the total performance of D-E curve is improved nearly 2%.