Tamper Localization Research Articles

A reversible image authentication scheme based on compressive sensing

In order to satisfy the requirement of reversible authentication as well as tamper localization and recovery, a reversible image authentication scheme based on compressive sensing (CS) is proposed. Double watermarks are employed, including a short one (perception Hash) for image integrity authentication and a long one for tamper localization and recovery. First, we embed the short watermark into the image in a reversible way. The embedding method is based on histogram modification of discrete Haar wavelet coefficients which is proposed in this paper. Then the long watermark, which is generated by CS sampling on the transformation coefficients of the non-overlapping image blocks, is registered to intellectual property rights (IRP) database for saving in a zero-watermarking way. At the authentication side, the receiver recovers the image after extracting the short watermark, and compares the Hash values generated from the recovered image with the short watermark for authentication. If the authentication is successful, the image can be completely restored to the original state in a reversible way; if the authentication fails, by utilizing the long watermark in the IRP database and CS reconstruction, it can achieve tamper localization and recovery. Meanwhile, experimental results show that the watermarked image has good imperceptibility. The proposed scheme is with good potential to be adopted for reversible image authentication.

Stereoscopic image tamper detection and self-recovery using hierarchical detection and stereoscopic matching

We propose a new watermarking algorithm for stereoscopic image tamper detection and self-recovery in three-dimensional multimedia services. Initially, left and right views of stereoscopic image are divided into nonoverlapping 2×2 blocks in order to improve the accuracy of tamper localization in an image. As the left and right views of a stereoscopic image are not independent from each other but have an inter-view relationship, every block of a stereoscopic image is classified into matching block or nonmatching block and then block disparities are obtained. Both matching blocks in the left and right views have similar pixel values, so that fewer bits are allocated for recovery watermark generation, which can increase the quality of watermarked stereoscopic images. A hierarchical tamper-detection strategy with a four-level checkup is presented to improve the accuracy of tamper localization. Additionally, two copies of block (matching block and nonmatching block) information are embedded into the stereoscopic image, and it assures the quality of tampered recovery. For the nonmatching block recovery, two copies of the partner block are embedded into their chaotic mapping blocks, which supply the second chance for tamper recovery. For the matching block recovery, the inter-view relationship between tampers of left and right views supplies the third chance for tamper recovery. Experimental results show that the proposed algorithm can not only detect and locate tampers in stereoscopic image more accurately but also recover the tampered regions better, compared with other algorithms.

A Fragile Watermark Method for Improving Medical Images Security

Aiming at the medical images security problem during storage and transmission, the author provides a fragile watermark method to protect it. And this method can be able to achieve integrity detection and accurate tampering localization. This method adopt s image block, chaotic modulation in watermark information and encryption to set password . The watermark information will be embedded to the least significant bits of original medical image’s sub - block area. Experimental results show that the algorithm has the following features: ( 1 ) T h e watermarked medical images has high and stable quality . ( 2 ) I t is sensitive to manipulations, and any manipulation of any pixel can be detected . ( 3 ) T he tampering localization can be accurate into 2×2 pixel area . ( 4 ) T he algorithm achieves the blind detection with high security.

A New Fragile Watermarking Based on Chaos

For existing airspace fragile authentication watermarking algorithm positioning accuracy and security issues, this paper presents a fully-fragile watermarking based on chaos for the integrity of the image content authentication and tamper localization. The algorithm uses the original image block, the calculation of each pixel in the image block high-bit gray value as the image feature watermark information. The chaotic sequence is encrypted and determines the position of the watermark bit is embedded watermark information, tampering with the positioning accuracy of an image block of 2 × 2 pixels. Experimental results show that the algorithm is simple, safe, with good practice.

A Novel Algorithm for Digital Watermarking for Image Tamper Localization and Recovery

A content-based and block-wise image authentication algorithm with location and recovery is presented. In this algorithm, the watermark of each block is its content-feature which is encrypted by md5, and it is embedded in another block which selected by an ergodic matrix of a chaotic sequence. That all security parameters are user dependent and can be computed at both ends individually based on Diffie-Hellman key exchange method makes the scheme not only robust against collage attack but also truly oblivious. The experiments demonstrate that the proposed scheme can detect and localize any tampering of size 8x8 pixels and above and can recover a 40% damaged image to an intelligible one.

A novel image tamper localization and recovery algorithm based on watermarking technology

In this paper, an effective self-embedding fragile watermarking scheme is presented. The watermark is generated by encoding the DCT coefficients of each 2×2 block and embedded into another block according to the block mapping. A non-linear chaotic sequence is used for generating the block mapping which can enhance the security of the algorithm. An improved tamper localization and recovery algorithm are performed. The experiment results show that the watermarked image has a high average peak signal-to-noise ratio. Furthermore, the tamper region can be successfully localized and exactly recovered, even if for the content-only tampering.

Content authentication for printed images utilizing high capacity data hiding

Authentication of content in printed images poses a challenge that cannot be addressed by conventional digital signature schemes because under the analog transport provided by the printing channel the verifier does not have access to the original digital content in pristine form. We present a method for cryptography-based authentication of the content in printed images that also provides the capability for identifying localized changes made by informed malicious attackers—key functionality that is missing in print scan robust hashes that have traditionally been used for print content authentication. The proposed method operates by embedding, within the printed image, an authentication signature that consists of an encrypted thumbnail of the image using a high capacity data hiding method for halftone images. To authenticate the content, the embedded signature is extracted from a scan of the printed image and, after decryption, compared with the printed content. An implementation of the method that incorporates human or automated verification and identifies potential local tampering by informed malicious attackers is developed and successfully demonstrated.

Effective management of medical information through ROI-lossless fragile image watermarking technique

In this article, we have proposed a blind, fragile and Region of Interest (ROI) lossless medical image watermarking (MIW) technique, providing an all-in-one solution tool to various medical data distribution and management issues like security, content authentication, safe archiving, controlled access retrieval, and captioning. The proposed scheme combines lossless data compression and encryption technique to embed electronic health record (EHR)/DICOM metadata, image hash, indexing keyword, doctor identification code and tamper localization information in the medical images. Extensive experiments (both subjective and objective) were carried out to evaluate performance of the proposed MIW technique. The findings offer suggestive evidence that the proposed MIW scheme is an effective all-in-one solution tool to various issues of medical information management domain. Moreover, given its relative simplicity, the proposed scheme can be applied to the medical images to serve in many medical applications concerned with privacy protection, safety, and management.

A Quick Glance at DigitalWatermarking in Medical Images -Technique Classification, Requirements, Attacks and Application of Tamper Localization

Digital watermarking is seen as a necessary and important field to be developed since the attacks and manipulations of digital documents and media are actively done. This paper surveys and reviews some basic theory about digital watermarking, such as the technique classification, requirements and possible attacks nowadays. Since all data in medical images are significantly important, the demand for the authentication is high. Therefore, this paper also focuses on a specific application of digital image watermarking for medical images which are tamper localization.

A Novel Self-Embedding Watermarking Scheme for Image Tamper Detection and Recovery

In this paper, an effective self-embedding fragile watermarking scheme is proposed. The watermark is generated by encoding the DCT coefficients of each 2×2 block and embedded into another block. A non-linear pseudo random sequence is used for generating the block mapping which can enhance the security of the algorithm. An improved tamper localization and recovery algorithm are performed. The experiment results show that the tamper region can be successfully localized and exactly recovered, even if under the content-only tampering.

A generalized tamper localization approach for reversible watermarking algorithms

In general reversible watermarking algorithms, the convention is to reject the entire cover image at the receiver end if it fails authentication, since there is no way to detect the exact locations of tampering. This feature may be exploited by an adversary to bring about a form of DoS attack. Here we provide a solution to this problem in form of a tamper localization mechanism for reversible watermarking algorithms, which allows selective rejection of distorted cover image regions in case of authentication failure, thus avoiding rejection of the complete image. Additionally it minimizes the bandwidth requirement of the communication channel.

Implementation of Technique for Image Authentication using Regular LDPC Codes

In this paper, we propose an approach using encryption technique and LDPC source coding for the image authentication problem. Image authentication is important in content delivery via untrusted intermediaries, such as peer-topeer (P2P) file sharing. Many differently encoded versions of the original image might exist. In addition, intermediaries might tamper with the contents. Distinguishing legitimate diversity from malicious manipulations is the challenge addressed in this research. The key idea is to provide a Slepian-Wolf encoded quantized image projection as authentication data which is again encrypted using a secret key cryptography before ready to send. This can be correctly decoded with the help of an authentic image as side information. This mechanism provides the desired robustness against legitimate variations while detecting illegitimate modification. The decoder incorporating expectation maximization (EM) algorithms can authenticate images which have undergone contrast, brightness and even warping adjustments. Our novel authentication system also others tampering localization by using inference over a factor graph that represents tampering models.

Object based dual watermarking for video authentication

Video cameras have been widely installed in public facilities for the surveillance applications. So, video authentication has becoming increasingly attractive. This paper presents a dual watermarking for video authentication based on moving objects. For each frame, the frame index, as a watermark is first embedded into the moving objects of the corresponding frame using a reversible watermarking method, aiming to detect the temporal tampering. Then the principle content and the details of the moving objects combined with the authentication code, as the other watermark, are embedded into the frame for spatial tampering location and recovery. Specially, a synthesized frame method is proposed for lossless recovery of moving objects and effective extraction of frame index. Statistical analysis and experiment results show that the proposed method can locate spatial, temporal and spatio-temporal tampering accurately. The spatial tampered regions can be recovered approximately and the moving objects can be restored completely when the tampered area is limited.

A data hiding method based on information sharing via PNG images for applications of color image authentication and metadata embedding

A new data hiding method via PNG images based on Shamir's (k, n)-threshold secret sharing scheme is proposed. The coefficients of the polynomial used by the Shamir's method are taken as carriers to carry given data. The data to be hidden then are transformed into partial shares and embedded into the alpha-channel plane of a cover PNG image. Undesired white noise created in the resulting stego-image is removed by skillfully mapping the computed share values into suitable ranges in the embedding process. An important application of the proposed method to color image authentication is also proposed, with detailed authentication algorithms for PNG images presented. Compared with existing methods, the proposed image authentication method possesses the merits of losslessness during image authentication, high sensitivity to image alterations, good tampering localization capability, and very low false acceptance and rejection ratios. Experimental results proving the effectiveness of the proposed methods are also included.

Revealing the Traces of JPEG Compression Anti-Forensics

Due to the lossy nature of transform coding, JPEG introduces characteristic traces in the compressed images. A forensic analyst might reveal these traces by analyzing the histogram of discrete cosine transform (DCT) coefficients and exploit them to identify local tampering, copy-move forgery, etc. At the same time, it has been recently shown that a knowledgeable adversary can possibly conceal the traces of JPEG compression, by adding a dithering noise signal in the DCT domain, in order to restore the histogram of the original image. In this paper, we study the processing chain that arises in the case of JPEG compression anti-forensics. We take the perspective of the forensic analyst, and we show how it is possible to counter the aforementioned anti-forensic method revealing the traces of JPEG compression, regardless of the quantization matrix being used. Tests on a large image dataset demonstrated that the proposed detector was able to achieve an average accuracy equal to 93%, rising above 99% when excluding the case of nearly lossless JPEG compression.

Reversible fragile watermarking for locating tampered blocks in 2D vector maps

For 2D vector maps, obtaining good tamper localization performance and original content recovery with existing reversible fragile watermarking schemes is a technically challenging problem. Using an improved reversible watermarking method and a fragile watermarking algorithm based on vertex insertion, we propose a reversible fragile watermarking scheme that detects and locates tampered blocks with high accuracy while ensuring recovery of the original content. In particular, we propose dividing the features of the vector map into different blocks, calculating the block authentication watermarks and embedding the watermarks with different watermarking schemes. While the block division ensures superior accuracy of tamper localization, the reversible watermarking method and the fragile watermarking algorithm based on vertex insertion provide recovery of the original content. Experimental results show that the proposed scheme could detect and locate malicious attacks such as vertex/feature modification, vertex/feature addition, and vertex/feature deletion.

A secure high capacity full-gray-scale-level multi-image information hiding and secret image authentication scheme via Tchebichef moments

The growth of image processing tools and applications has made it easy for multi-media content such as music, audio, and video to be manipulated or forged during transmission over the Internet. Efforts, such as information hiding in steganography, have been unable to secure data transmission and prevent its manipulation. Usage of coding theory, including cryptography, is not full proof in the sense that an unauthorized intruder may inject (tampering) and incorporate unintended data to the messages, which can tamper the transmitted data. There is a need for more transparent message information hiding schemes along with information content verification and authentication, as well as accurate tampering detection. In particular, as it is well known, in many current steganography methods, widely used for image information hiding, there are various technical challenges associated with hiding large amounts of image information in images. Some of these challenges relate to which locations, in a given carrier image, information has to be hidden in order to guarantee transparency of the resulting watermarked images, to the ability to extract hidden information accurately, to the performance of hidden secret information authentication and verification at the receiving end, to the dependency of the hidden information on a given carrier image, to the robustness of information hiding schemes to affine transformations such as rotation, and to the amount of data and number of full-scale images one can embed in a given single image carrier. Additionally, as it is well known, many of the existing stenography methods are based on the Discrete Fourier Transform (DFT), the Discrete Cosine Directors (DCT), or the Discrete Wavelength Transform (DWT) methods, which result in high Bit Error Rate (BER) of the extracted data. In this paper we present a secure high capacity image information hiding scheme where two full separate arbitrary full-scale gray level images (versus binary), one hidden information image and one authentication watermark image are hidden/embedded in the Tchebichef moments of a carrier image with very high imperceptibility. Here the second watermark image is used for identification and content integrity verification and authentication of the hidden secret image. Both the hidden secret hidden image and the authentication watermark image are of the same size as that of a given arbitrary carrier image. In particular, with the cost of computer memory getting lower and the bandwidth of transmission channels getting larger, we show how three different watermarked images, but the same to a naked eye, are produced and transmitted to achieve the desired advantages of high accuracy, security, authentication and verification of the recovered information. To the best of our knowledge, this two-full-scale gray images data hiding and hidden secret image information verification and authentication method is the first attempt of its sort. We show here the robustness of the proposed scheme to affine transformations such as rotation, scaling, and translation, the proposed scheme's high image malicious tampering detection and tampering localization and its high quality extracted recovered and authenticated hidden secret images. Additionally, in order to as much as possible keep the integrity of the received information, when watermarked images are rotated during transmission, a new image rotation estimation and recovery algorithm is presented as part of the proposed information hiding scheme. We show the effect of intended tampering attacks namely, cropping, noise, low-pass and high-pass filtering on the presented scheme. We also show how the extracted information accuracy is generally independent of the carrier image, and we present a mathematical analysis for characterizing the conditions under which transparency of the hidden embedded information is generally achieved for any given arbitrary carrier image. The case of how to extract the hidden information when one or two of the watermarked images is (are) lost is also tackled. Finally, experimental results on real images are presented to illustrate the efficiency and capabilities of the proposed method.

A block-based watermarking scheme for image tamper detection and self-recovery

AbstractIn this paper, we present an effective block-based digital fragile watermarking scheme for image tamper detection and recovery. The proposed scheme embeds watermarks consisting of the authentication data and the recovery data into image blocks. It adopts parity check and the intensity-relation check to thwart various malicious attacks. In the tamper detection process, instead of independently testing the embedded authentication data of each block, we take the block-neighbourhood into account and utilize a hierarchical structure to determine the legitimacy of image blocks. Experimental results show that the proposed scheme can effectively resist collage attack, vector quantization (VQ) attack and constant-average attack, while sustaining superior accuracy of tamper localization. Furthermore, the results reveal that the tampered images can be successfully self-recovered with acceptable visual quality.

Block Compressive Sensing Based Image Semi-fragile Zero-watermarking Algorithm

To aim at content authentication and integrity protection problems in digital image application,a block compressive sensing based image semi-fragile zero-watermarking(BCS-SFZ) algorithm is proposed.Firstly,the image is divided into several sub blocks.The block size can be adjusted according to the data quantity of watermark and tamper localization accuracy.Secondly,each image block is observed in accordance with the theory of compressive sensing.Finally,the measurements are registered and preserved as the zero-watermarking.The experimental results show that BCS-SFZ can accurately locate the illegal tampering and recover the tampered area with the watermark information.The introduction of compressive sensing theory provides secrecy guarantee for the algorithm,and is conducive to synchronization of imaging and generating watermark.Also,the algorithm is simple and has a low computational complexity.

A novel chaos-based fragile watermarking for image tampering detection and self-recovery

In this paper, a novel watermarking approach is proposed to provide enhanced tampering localization and self-recovery. A cross chaotic map is used to confuse the blocks generated by the original image. A sister block embedding scheme is proposed to improve the recovery effect after tampering. Flags and a combination of the most significant bit (MSB) and the least significant bit (LSB) mechanism are applied to improve the tampering detection rate and the defense of attacks. And an optimization scheme is given to make the recovered image have advanced visual effects. Experiment results show that the proposed schemes are more secure and have better effect on tampering detection and recovery even though the tampered area is relatively large.