基于Huffman码表索引的MP3Stego隐写分析方法

MP3Stego是经典的MP3音频隐写算法之一。通过分析MP3Stego隐写算法对编码器内循环模块的影响,发现哈夫曼码表索引值在隐写前后发生了不同程度的改变。在此基础上,从待检测的MP3音频的解码参数中提取Huffman码表索引值,计算其二阶差分值,将其作为隐写分析的特征,结合SVM支持向量机实现隐写分析。实验结果表明,所提取的特征能够有效地反映MP3Stego算法在不同嵌入速率下的隐写痕迹。     

Steganalysis for MP3Stego using differential statistics of quantization step

MP3Stego is a typical steganographic tool for MP3 audio, which embeds secret message into MP3 audio according to the parity of the block length. In this paper, a detection method for MP3Stego based on the differential statistics of quantization step is present. By analyzing the algorithm of MP3Stego, we find that the quantization step which is an important parameter of MP3 encoding is affected during embedding. The standard deviation of the second-order differential sequence from quantization step is adopted as the classification feature. Experimental results indicate that the proposed algorithm is effective in detecting MP3Stego and can achieve better detection performance than the existing algorithms.     

基于联合失真的AAC安全隐写算法

随着互联网技术的普及,越来越多的音视频通信应用融入到了人们的日常生活中.AAC(Advanced Audio Coding),作为目前互联网应用中使用最广泛的音频压缩编码标准之一,拥有优秀的压缩效果和出色的音频质量,使得越来越多的音视频作品利用AAC进行编码传输,这也为信息隐藏提供了新的、更多、更好的隐写空间.本文分别...     

Detection of MP3Stego exploiting recompression calibration-based feature

MP3Stego is a typical steganographic tool for MP3 audio. Once the cover audio is unavailable, it is hard to distinguish between background noise and steganographic distortion. In this work, the MP3Stego algorithm has been analyzed from a warden’s perspective. It is observed that the number of bits in the bit reservoir will be disturbed when the secret message is embedded. In addition, a reliable estimation of cover audio is obtained by the proposed recompression calibration. The calibrated features are classified with support vector machine technique. Experimental results show that the proposed scheme is effective and gets good performance, especially when the embedding rate is not less than 0.01 %. The results also shows that the proposed scheme can achieve lower false positive rate comparing to the existing algorithms.     

分级安全的文本隐写方法

针对单一数据类型隐写方法安全性不高、隐写容量不足等问题,提出了一种具有分级安全的文本隐写方法。首先,将整个载体文档中的多种类型的数据作为备选隐写载体,以不同类型数据的隐写特点和隐写分析技术为评估依据定义隐写安全等级,构建了一个多类数据融合的分级安全隐写模型。然后,根据秘密信息的长度自适应确定安全等级,并利用分级安全隐写模型将秘密信息分块地嵌入在同一个载体文档相互独立的多个不同类数据中。理论分析及实验结果表明,与现有基于单一数据类型隐写方法相比,所提方法扩大了隐写容量,在嵌入等量的秘密信息情况下,降低了文档中同一类载体数据的统计特征改变程度,提高了秘密信息的整体安全性。     

Steganalysis of MP3Stego with low embedding-rate using Markov feature

MP3Stego is a typical steganographic tool for MP3 audios, whose embedding behavior disturbs the intrinsic correlation of the quantized MDCT coefficients (refer to as QMDCTs). In this paper, the Markov feature captured this correlation were designed based on the QMDCTs. The feature is sensitive to the subtle alteration caused by MP3stego embedding even at a low embedding-rate. In addition, some work on QMDCT pre-processing, threshold selection and feature optimization were applied to feature construction, which contribute to improving the detection accuracy and reducing the computational complexity of the proposed scheme. Experimental results show that our approach can effectively detect MP3Stego of low embedding-rate and outperforms the prior arts.     

A steganographic method based upon JPEG and particle swarm optimization algorithm

In this paper, a novel steganographic method, based on JPEG and Particle Swarm Optimization algorithm (PSO), is proposed. In order to improve the quality of stego-images, an optimal substitution matrix for transforming the secret messages is first derived by means of the PSO algorithm. The standard JPEG quantization table is also modified to contain more secret messages. The transformed messages are then hidden in the DC-to-middle frequency components of the quantized DCT coefficients of the cover-image. Finally, a JPEG file with secret messages is generated through JPEG entropy coding. We compare our algorithm with Chang et al.’s JPEG-based steganographic algorithm. The experimental results show that our proposed method has larger message capacity and better image quality than Chang et al.’s. In addition, our method also has a high security level.     

大容量 MP3 比特流音频隐写算法

通过对MP3编解码算法原理的研究,提出了一种基于小值区哈夫曼编码特点的信息嵌入方法--码字映射替换规则,进而实现了一种能在MP3压缩文件的比特流中隐藏大量信息的盲检测隐写算法.算法先对载体mp3文件部分解码,搜索出适合嵌入的小值区码字,然后按规则修改比特流中的相应码字来嵌入秘密信息.实验结果表明,算法的容量高于MP3Stego,计算复杂度低,同时可保证不可感知性,并具有一定的不可检测性,能抵抗针对MP3Stego的隐写分析算法.     

A novel steganalysis for TPVD steganographic method based on differences of pixel difference histogram

Tri-way Pixel Value Differencing (TPVD) steganographic method is a new modified version of another well-known method called PVD, which intents to increase embedding capacity and security of its successor by hiding secret bits in both vertical and diagonal edges of a cover image, in addition to the horizontal edges used in PVD. In this paper, it is shown that the histogram of difference values of a stego image under the TPVD algorithms is vulnerable to a particular statistical analysis. So, a new steganalytic measure named Growing Anomalies is introduced that its value has a linear relationship with secret message rate. It is shown empirically and theoretically that proposed steganalysis method based on this measure can estimate the amount of secret bits with a negligible error rate. The proposed steganalyser can classify test images as stego or cover with 97% accuracy when they contain more that 10% secret data. Implementation results indicate that proposed method can estimate secret message rate with an average accuracy of 95%.     

A New Steganographic Method for Data Hiding in Microsoft Word Documents by a Change Tracking Technique

A new steganographic method for data hiding in Microsoft Word documents by a change tracking technique is proposed. The data embedding is disguised such that the stegodocument appears to be the product of a collaborative writing effort. Text segments in the document are degenerated, mimicking to be the work of an author with inferior writing skills, with the secret message embedded in the choices of degenerations. The degenerations are then revised with the changes being tracked, making it appear as if a cautious author is correcting the mistakes. The change tracking information contained in the stegodocument allows the original cover, the degenerated document, and, hence, the secret message to be recovered. The extra change tracking information added during message embedding is vital in a normal collaboration scenario, and so hinders ignorant removals by skeptics. Experiments demonstrate the feasibility of the proposed method     

基于Huffman编码的文本信息隐藏算法

自然语言句子可以变换为词性标记串或句型。该文提出了基于句型Huffman编码的信息隐藏算法,根据句型分布构造Huffman编码,秘密信息解码为句型。句型在载体文本中的位置是密钥,对句型作Huffman压缩编码即可提取秘密信息,给出了信息隐藏容量公式。该算法不需要修改载体文本。     

Color local complexity estimation based steganographic (CLCES) method

In this paper we present the color local complexity estimation based steganographic (CLCES) method that is able of both preventing visual degradation and providing a large embedding capacity. A preprocessing stage is applied in the proposed scheme to improve the steganography security. The embedding capacity of each pixel is determined by the local complexity of the cover image, allowing good visual quality as well as embedding a large amount of secret messages. We classify the pixels using a threshold based on the standard deviation of the local complexity in the cover image to provide a compromise between the embedding capacity and the image visual quality. The experimental results demonstrated that the algorithm CLCES proposed produces insignificant visual distortion due to the hidden message. It provides a high embedding capacity that is superior respect to the offered by the existing schemes. The proposed method is a secure steganographic algorithm; it can resist the image quality measures (IQM) steganalysis attack. The RGB, YCbCr, and HSV color spaces are incorporated in the proposed scheme to ensure that the difference between the cover image and the stego-image which is indistinguishable by the human visual system (HVS). Finally, the proposed scheme is simple, efficient, and feasible for the adaptive steganographic applications.     

基于注意力机制的高容量通用图像隐写模型

随着深度学习与隐写技术的发展,深度神经网络在图像隐写领域的应用越发广泛,尤其是图像嵌入图像这一新兴的研究方向.主流的基于深度神经网络的图像嵌入图像隐写方法需要将载体图像和秘密图像一起输入隐写模型生成含密图像,而最近的研究表明,隐写模型仅需要秘密图像作为输入,然后将模型输出的含密扰动添加到载体图像上,即可完成秘密图像的嵌入过程.这种不依赖载体图像的嵌入方式极大地扩展了隐写的应用场景,实现了隐写的通用性.但这种嵌入方式目前仅验证了秘密图像嵌入和恢复的可行性,而对隐写更重要的评价标准,即隐蔽性,未进行考虑和验证.提出一种基于注意力机制的高容量通用图像隐写模型USGAN,利用注意力模块, USGAN的编码器可以在通道维度上对秘密图像中像素位置的扰动强度分布进行调整,从而减小含密扰动对载体图像的影响.此外,利用基于CNN的隐写分析模型作为USGAN的目标模型,通过与目标模型进行对抗训练促使编码器学习生成含密对抗扰动,从而使含密图像同时成为攻击隐写分析模型的对抗样本.实验结果表明,所提模型不仅可以实现不依赖载体图像的通用嵌入方式,还进一步提高了隐写的隐蔽性.     

基于相同压缩速率下的MP3双压缩检测方法

MP3是目前应用最为广泛的音频格式。然而,利用各种音频编辑软件可以很方便地对MP3音频文件进行篡改。通过对相邻压缩次数形成的MP3音频之间量化后的MDCT系数不相同的个数进行统计分析,提出了一种基于相同压缩速率下的MP3双压缩检测方法。该方法有助于MP3音频文件的篡改取证。实验结果表明,该方法具有较好的检测率。     

Improved Dual-image Quality with Reversible Data Hiding Using Translocation and Switching Strategy

Dual-image reversible data hiding (RDH) is a technique for hiding important messages. This technology can be used to safely deliver secret messages to the recipient through dual images in an open network without being easily noticed. The recipient of the image must receive the two stego-images before the secret message can be completely retrieved. Imperceptibility is one of the main advantages of data hiding technology; to increase the imperceptibility, the quality requirements of the stego-images are relatively important. A dual steganographic image RDH method, called a DS-CF scheme that can achieve a better steganographic image quality using the center folding (CF) strategy. In this paper, we developed a translocation and switching strategy (TaS) to shorten the distances between the stego-pixel coordinates and the cover pixel coordinates after information being hidden. Compared with the DS-CF scheme, our proposed DS-TaS scheme can effectively improve the quality of the steganographic images at the same level of embedding capability. The experimental results show that the PSNR of our DS-TaS scheme at = 1 was 55.66 dB, which is an increase of 1.5 dB, and is 51.43 dB for = 2, 46.66 dB for = 3, and 40.91 dB for = 4. In addition, the PSNR values of the stego images was increased by 1.5, 0.29, 0.29, and 0.19 dB, respectively. This shows that our proposed dual-image RDH method can optimize the visual quality of the stego-images and is better than many other dual-image RDH techniques.     

On the Security of “A Steganographic Scheme for Secure Communications Based on the Chaos and the Euler Theorem”

This paper contains a security analysis of the construction of a public key steganographic system based on chaos theory and the Euler theorem (PKS-CE) as proposed by Lou and Sung in a previous issue of this transactions. Our analysis results in attack strategies on two different layers: first, we identify weaknesses of the embedding function, which allow a passive warden to tell steganographic images from clean carriers apart. Second, we show that the allegedly asymmetric trap-door function in fact can be efficiently inverted solely with the knowledge of its public parameters, thus revealing the secret message as plain text to a passive adversary. Experimental results from a re-implementation further indicate that the claimed robustness of the embedded message against transformations of the carrier medium was far too optimistic. Finally, we demonstrate that a secure alternative system can easily be constructed from standard primitives if the strong assumptions made in PKS-CE for the mutual key exchange can actually be fulfilled.     

基于线性分组码和湿纸码的三层信息隐藏算法

在LSB算法、线性分组码和湿纸编码的基础上,提出一种高效数据隐藏算法。秘密信息分3层嵌入载体数据中：第1层采用 LSB算法嵌入一部分秘密信息。第2层采用湿纸编码调整方向,用F5算法在n bit信息中嵌入k bit秘密信息。第3层湿纸编码在调整 第2层嵌入方向的同时携带一部分秘密信息。分析结果表明,该算法在相同嵌入效率情况下具有较大的嵌入容量。     

采用SVR模型进行嵌入率估计的隐写分析方法

为解决大多数通用隐写分析算法不能检测秘密信息长度的问题,提出了一种改进的能估计秘密信息长度的通用隐写分析方法。从隐写图中提取描述DCT域系数相关性的132维特征,用支持向量回归机学习图像特征和相应嵌入改变率之间的映射关系并建立模型,根据映射模型估计测试隐写图的嵌入改变率。使用典型的嵌入算法:F5、outguess与MB进行测验,仿真结果显示提出的秘密信息长度估计算法是切实可行的。     

使用四叉树分割进行自适应空域隐写

目的 针对自适应隐写术可有效避免对载体敏感区大量修改的关键问题,为间接提高安全性和增大隐写容量,在四叉树分割和自适应像素对匹配（APPM）的基础上提出一种自适应空域隐写术。方法 首先该方法以图像块的纹理复杂度作为一致性测度并且设置图像块大小为判别准则进行图像分割,根据四叉树分割结果中面积较小的图像块属于复杂区域,较大的属于平滑区域,按照图像块面积大小将图像分成由高复杂、中复杂、低复杂三大区域构成。其次嵌密方式采用APPM,根据密信容量和载体图像选择进制数B。最后,为了保证安全性和提高容量,优先选择高复杂区嵌入不低于B进制的密信,在中复杂区进行B进制的密信嵌入,在低复杂区选择不高于B进制的密信嵌入。结果 为了验证提出的方法,选8幅经典图作为实验,在嵌入率1.92 bit/pixel的情况下,与已有PVD系列算法和DE算法相比具有更高的PSNR值,PSNR值高达48 dB。此外与APPM算法比较,在嵌入率2.5 bit/pixel情况下,该算法的平均KL距离相比传统APPM算法减小了25.37%,平均一阶Markov安全指标值相比传统APPM算法减小了12.11%,对应的平均PSNR值相比传统APPM算法提高0.43%,在嵌入率1.5 bit/pixel情况下,该算法的平均KL距离相比传统APPM算法减小了37.84%,平均一阶Markov安全指标值相比传统APPM算法减小了26.61%,对应的平均PSNR值相比传统APPM算法提高1.56%。此外,从RSP图库中随机选1 000幅图作为数据集,在嵌入率0.5,0.6,0.7,0.8,0.9和1.0 bit/pixel条件下,结合SPAM特征和SVM分类器的最小平均错误率均高于LSB系列经典算法和APPM算法。结论 1）考虑了人类视觉系统对图像不同区域的敏感性不同,通过对图像进行四叉树分割预处理,优先选择非敏感区进行隐写,保证了一定的安全性要求,低嵌入率下抗SPAM检测和统计不可见性方面比较有优势。2）在四叉树分割中,对于隐写前后图像的四叉树分割结果不同的异常情况,采用一种图像块纹理复杂度调整方案,保证了密信正确完整提取。3）利用了APPM算法的大容量特性,可以隐写嵌入率大于1 bit/pixel的密信,比较适用于大容量的密信隐写,而且可以嵌入任意进制的密信,最大程度地减少嵌入失真,此外,进行了四叉树分割预处理,在安全性方面优于传统APPM算法。     

基于可容忍失真范围的数字图像隐写方法研究

以往的基于可容忍失真范围的隐写方案可以将隐写引起的失真控制在一定范围,但需要同时具备含密图像与原始图像才能提取秘密信息。提出了一种新的基于可容忍失真范围的隐写方案,该方案以一定质量因子的JPEG压缩作为可容忍失真,嵌入信息时仅在可容忍失真范围内改动原始图像,并具有含密图像的JPEG压缩版本与原始图像的JPEG压缩版本完全一致的特性,因此接收端不需原始图像,只要将含密图像与其JPEG压缩版本相减,便可提取出秘密信息,克服了原有此类方法需要原始图像才能提取秘密信息的缺点。实验结果表明,用该方案隐写所得到含密图像不仅在质量上优于其对应的JPEG压缩版本的质量,而且具有一定的抗分析安全性。