Earticle

The discrete wavelet transform (DWT) has good multi-resolution decomposition characteristic and its low frequency component contains the basic information of an image. Based on this, a fragile watermarking using the local binary pattern (LBP) and DWT is proposed for image authentication. In this method, the LBP pattern of low frequency wavelet coefficients is adopted as a feature watermark, and it is inserted into the least significant bit (LSB) of the maximum pixel value in each block of host image. To guarantee the safety of the proposed algorithm, the logistic map is applied to encrypt the watermark. In addition, the locations of the maximum pixel values are stored in advance, which will be used to extract watermark on the receiving side. Due to the use of DWT, the watermarked image generated by the proposed scheme has high visual quality. Compared with other state-of-the-art watermarking methods, experimental results manifest that the proposed algorithm not only has lower watermark payloads, but also achieves good performance in tamper identification and localization for various attacks.

As the major source of information, digital images play an indispensable role in our lives. However, with the development of image processing techniques, people can optionally retouch or even forge an image by using image processing software. Therefore, the authenticity and integrity of digital images are facing severe challenge. To resolve this issue, the fragile watermarking schemes for image authentication have been proposed. According to different purposes, the fragile watermarking can be divided into two categories: fragile watermarking for tamper localization and fragile watermarking with recovery ability. The fragile watermarking for image tamper localization can only identify and locate the tampered regions, but it cannot further restore the modified regions. In some cases, image recovery for tampered regions is very essential. Generally, the fragile watermarking for image authentication and recovery includes three procedures: watermark generation and embedding, tamper localization, and image self-recovery. In this article, we make a review on self-embedding fragile watermarking methods. The basic model and the evaluation indexes of this watermarking scheme are presented in this paper. Some related works proposed in recent years and their advantages and disadvantages are described in detail to help the future research in this field. Based on the analysis, we give the future research prospects and suggestions in the end.

기존 이미지 기반 그래픽 패스워드는 특정 이미지에 종속되어 이미지 유출 및 숄더서핑(shoulder surfing) 공격에 취약하다. 본 논문은 이미지 자체가 아닌 이미지 속 '시각적 의미(visual semantic)'를 비밀키로 활용하는 이미지 독립적 시각 의미 인증(Visual Semantic Authentication, VSA) 프레임워크를 제안한다. Grounding DINO와 CLIP을 결합하여 객체, 속성, 수량, 2×2 4분면 공간 정보를 추출하고, 유연한 범위 논리(FlexibleRange Logic)와 해시 기반 비밀 바인딩(hash-based secret binding)으로 보안성과 가용성을 동시에 확보한다. COCO 2017 벤치마크 1,009장에 대해 5단계 난이도 16개 정책을 평가한 결과, 규칙 복잡도에 따라 FAR이 51.73%에서 0%까지 단조 감소하는 보안 기울기(security gradient)를 확인하였다. 또한 벤치마크에서 정책별 양성 이미지를 자동 식별하여 FRR을 평가하고, 정책 복잡도와 이미지 가용성 간의 보안-사용성 트레이드오프를 정량적으로 제시하였다.

Conventional graphical passwords are tied to specific images, making them vulnerable to image leakage and shoulder-surfing attacks. This paper proposes an Image-Agnostic Visual Semantic Authentication (VSA) framework that uses visual semantics within images as secret keys. The framework combines Grounding DINO and CLIP to extract objects, attributes, quantities, and 2×2 quadrant spatial information, while Flexible Range Logic and hash-based secret binding ensure both usability and server-opaque protection. Experiments on 1,009 COCO 2017 benchmark images across 16 security policies in five difficulty levels demonstrate a monotonic FAR gradient from 51.73% to 0% with increasing rule complexity. FRR is also evaluated by automatically identifying positive images from the benchmark, and the trade-off between policy complexity and image availability is quantitatively characterized.

Digital Watermarking is a technique which embeds a watermark signal into the host image in order to authenticate it. In our previous work [1], a binary watermark pattern was constructed from the information content of the image by selecting the minimum value from every block of size 2x2, and was disordered with the help of Arnold Transform but which was not showing a fine robustness against compression and rotation operation. As a solution to this issue, an innovative watermarking scheme is proposed. According to this, the low frequency subband of wavelet domain and the rescaled version of original image are utilized in the watermark construction process. A scrambled version of watermark is obtained with the help of Arnold Transform. The operation of embedding and extraction of watermark is done in high frequency domain of Discrete Wavelet Transform since small modifications in this domain are not perceived by human eyes. This watermarking scheme deals with the extraction of the watermark information in the absence of original image, hence the blind scheme was obtained. Peak Signal to Noise Ratio (PSNR) and Similarity Ratio (SR) are computed to measure image quality. In addition, the competency of the proposed method is verified under common image processing operations and a comparative study is made against the previous technique.

Fragile watermarking has the characteristics where the inserted watermark should be easily breakable for a trivial tampering of the image. So, fragile watermarking technique is proposed for the purpose of authentication or tamper detection. In this paper, we propose an efficient image tamper detection method using block-wise technique which is able to detect the tamper locations. In the proposed method, a digital signature is generated from the hash code of the blocks of the final level where the watermark is inserted and the blocks of the upper level where those blocks are included in the image division process and this signature is used as the watermark, which is randomly inserted into selected image blocks. As the result of experiment, the proposed method was confirmed to be able to detect the tampered parts of the image without testing the entire block of the watermarked image.

We propose a watermarking scheme for the authentication of binary images. We transform the image using the binary wavelet transform and partition the resulting coefficients into tree-structured blocks. The size of each block is decided by the number of flippable coefficients in the block. The flippable coefficients are found in the frequency domain by investigating high frequency coefficients. A random bit sequence generated by the block identifying key is embedded in the flippable coefficients in each block. Block-wise localization of tampered regions is accomplished with imperceptible visual degradations. Counter-measures against the vector quantization attack to which most existing watermarking schemes are vulnerable may also be implemented in our scheme

The central idea of this paper is to propose an innovative watermarking scheme for digital image authentication which embeds watermark into the host image and provides qualities such as imperceptibility, robustness and security. A watermark signal is constructed from feature of original image instead of using external watermark. Several pixels are randomly selected from original image, so that all of them have a valid 3x3 neighborhoods. A binary sequence is constructed from those pixels by comparing them against average values of neighborhoods. The binary sequence is then converted into a watermark pattern in the form of a Hankel matrix to improve security of watermarking process and is then embedded within the host image. The operation of embedding and extraction of watermark is done in high frequency domain of Discrete Wavelet Transform since small modifications in this domain are not perceived by human eyes. This watermarking scheme deals with the extraction of the watermark information in the absence of original image, hence the blind scheme was obtained. The proposed algorithm was verified under common image processing attacks such as salt & pepper noise, Gaussian noise, median filtering, linear filtering, JPEG compression, blurring, scaling, intensity adjustment and histogram equalization. Peak Signal to Noise Ratio (PSNR) and Similarity Ratio (SR) are computed to measure imperceptibility and robustness of the watermark respectively.

Digital images are present everywhere on magazine covers, in newspapers, in courtrooms as evidences, and all over the Internet signifying one of the major ways for communication nowadays. The trustworthiness of digital images has been questioned, because of the ease with which these images can be manipulated in both its origin & content as a result of tremendous growth of digital image manipulation tools. Digital image forensics is the latest research field which intends to authorize the genuineness of images. This survey attempts to provide an overview of various digital image forgeries and the state of art passive methods to authenticate digital images.

This paper proposes a novel scheme for securing and authenticating digital data. Although, the experiments were applied to digital images, it is valid for sound, and video without any modifications of the core scheme. The developed scheme could be applied to the encoded data at the sender and the receiver sides, apart from the compression and decompression processes. The watermark information is generated automatically from the input data and hidden into the Least Significant Bits (LSBs) of specified pixels according to innovative criteria. Experimentally, the received data is authenticated if it is 100% match the sent data, exposing both geometric and signal processing attacks. The hidden watermark is completely invisible, achieving Peak Signal to Noise Ratio (PSNR) more than 67 decibels (dB) for grayscale images that vary in size and content. The developed scheme is evaluated by verifying images of the testing set before and after tampering, showing comparable performance. A comprehensive analysis for the experimental results revealed performance and efficiency of the proposed scheme is presented. An extensive review of previous work concerning image authentication approaches is presented, showing the need for robust and powerful authentication scheme.

This paper proposes a ‘Reversible Watermarking scheme for Image Authentication’ (RWIA) using Integer Wavelet Transform that satisfies the requirements of imperceptibility, capacity, and robustness. The proposed algorithm hides the data and the bookkeeping information in the high frequency subbands of CDF (2,2) integer wavelet coefficients whose magnitudes are similar to a certain predefined threshold. Histogram modification is applied as a preprocessing to prevent overflow/underflow. The embedding technique is based on the parent-child structure of the transformed coefficients called “quadruple wavelet tree” (QWT). The paper provides a comprehensive analysis of the existing methods. The experimental results evaluated by the proposed technique on different grayscale images and a comparison with existing methods is found better. The watermark is extracted to an acceptable degree of normalized cross correlation even in the presence of attacks like geometric transformations and JPEG compression.

Progressive image transmission (PIT) provides multiple image resolutions that favors a time-critical or a low-band channel environment. In this paper, a PIT based watermarking for multi-resolution image authentication is proposed. The image content with progressive characteristic is taken as the authentication code. The authentication code is then embedded according to multi-resolution image encoding. The experimental results show the validity of the proposed scheme. Malicious operations are detected progressively from multi-resolution images. The significant tampering can be detected firstly and slight tampering is detected in the later authentication stages. Furthermore, the tampered locations can be located correctly.

In this paper, a new oblivious fragile watermarking using discrete cosine transform is proposed. It is inspired by Wong's public key watermarking scheme proposed in 1998 and aims to improve its vulnerability towards possible attacks indicated by Barreto and Holliman. Instead of making use of contextual information and making it an inter-block dependent scheme, as suggested by Barreto, we adopt another approach to retain its blockwise independent property. Our scheme can avoid the conditions necessary for such attacks to be feasible. Furthermore, our scheme extracts the inherent image features and embeds them into this image as the watermark. This relieves users from having to maintain a database of watermarks from various sources. Experimental results show that the watermark insertion procedure has little effect on the visual quality of the watermarked image. They also show our scheme can locate the modifications made to the watermarked image, including image scaling, cropping, geometric distortion, pixel value changes, etc.

Healthcare institution that handles a number of patients, opinions is often sought from different experts. It demands the exchange of the medical history of the patient among the experts which includes the medical images, prescriptions and electronic patient records (EPR) etc. In order to reduce storage and transmission cost, data hiding techniques are used to embed patient information with medical images. In medical imaging applications, there are stringent constraints on image fidelity that strictly prohibit any permanent image distortion by the watermarking or data hiding. Authenticity is another important aspect in medical image watermarking. This paper proposed modified difference expansion watermarking using LSB replacement in the difference of virtual border for data hiding in medical images. The Class Dependent Coding Scheme (CDCS) is used to encode the EPR data so that embedding capacity can be increased. The image hash is calculated using MD5 to provide authentication. Experimental results show that proposed scheme provide us large data hiding capacities along with very high PSNR values as compared to earlier EPR data hiding techniques.

Image forgery is a major issue in today's digital publishing and printing. Now a day’s system can be used for forensic purpose to validate the authenticity of an image. In this paper we present an approach for image forgery authentication. We observe that a non morphed and non forged image shows homogeneity in non spectral domain. This homogeneity is lost when any forgery or morphing is applied on the images. We therefore apply a set of transform over the images. We combine DCT statistics, LBP features with curvelet statistics and Gabor transform of the images to represent an image in the transformed domain. CASIA image dataset with seven thousand authentic and same numbers of tempered images is used to verify the technique. We divide the dataset into equal halves to perform training and testing. Transformed images are used to train Hidden Markov model as HMM can extract probabilistic state information from a large statistical model. A test images is tested in transformed domain by HMM with log likelihood estimator. In case HMM returns an indeterminist result or multiple subset of result, the transformed test image is tested with two class SVM classifier with RBF kernel. Results show that the accuracy of the system is over 89% for 500 test instances.

Authentication can be considered as the first wall of protection from unauthorized access of any system and most notably cloud environment. Its aim is to verify user’s identity and thus the user’s legitimacy of access to services. Nowadays, The most used method for policing user access is text password. However, Several studies have shown the inadequacy of this method due to the growth of network threats. In order to mitigate the deficiency of text password scheme, we propose an image-based one-time password scheme for the cloud environment called (imOTPc). The scheme uses an image as one-time password and mobile network, which makes the system more robust and, therefore, can withstand common types of attacks. The security of the proposed scheme is based on the one-way hash function, secret extraction and the IMEI.

CAPTCHAs are an imperative and broadly used modern Internet technology to reduce the risk of reducing the computerized agents to programmatically use web connected resources such as online e-mail accounts, online polls, Web-based comment systems, Web-based SMS portals and so on. The designing of security algorithms utilizing captcha can be a useful security mechanism. There are several security attacks and survival of many phishing websites. In current systems, two factor authentications, One Time Password (OTP) are used to overcome these issues. In case of OTP, mobile technology is used to send the password to the client for confirmation, in some cases, mostly handheld mobiles may not be within the reach or there may be several other issues like network traffic and delay in receiving passwords. These problems decrease the capability of authentication. Here the proposed system is technology independent and behavior based authentication system, where system performs complete authentication through website using Image CAPTCHA. Behavior based authentication is done through appropriate selection and cropping of image at the accurate location. This proposed system ultimately enables us to substantiate whether the user is an authenticated user and website is an authenticated website The performance of the system has been analyzed using shoulder surfing, brute force, dictionary, random and reply attack to prove the web security.

Advancements in information and communication technologies have made it easier to forge printed documents these days. Forgery of printed document could have serious repercussions including financial losses, so maintaining the reliability of valuable documents is one that is timely and necessary. The document authentication approach in this study is one that involves tracing of the origin of a document through its contents. The approach explores viability of embedding certain information on printed documents for authentication purposes. Such information could be extracted from the content of documents, which can be divided into two: the context, which includes the text, figures and shapes and the visual attributes of the document, such as its color and design. In short, this study presents a practical and secure method to prevent the forgery of important documents. The proposed method makes use of the public key infrastructure (PKI) and Quick Response (QR) code and the cryptographic hash algorithm shows robustness to printing or scanning noise. The method also makes use of the unique tracking numbers such as device serial numbers, and timestamps enhance the security. To test the feasibility of the method several experiments were perform and the experimental results showed significant improvement in printed document authentication.

The double-random phase encryption (DRPE) algorithm is a robust technique for image encryption, due to its high speed and encoding a primary image to stationary white noise. Recently it was reported that DRPE in the Fresnel domain can achieve a better avalanche effect than that in Fourier domain, which means DRPE in the Fresnel domain is much safer, to some extent. Consequently, a method based on DRPE in the Fresnel domain would be a good choice. In this paper we present an image-authentication method which uses only partial phase information from a double-random-phase-encrypted image in the Fresnel domain. In this method, only part of the phase information of an image encrypted with DRPE in the Fresnel domain needs to be kept, while other information like amplitude values can be eliminated. Then, with the correct phase keys (we do not consider wavelength and distance as keys here) and a nonlinear correlation algorithm, the encrypted image can be authenticated. Experimental results demonstrate that the encrypted images can be successfully authenticated with this partial phase plus nonlinear correlation technique.