Color Visual Secret Sharing for QR Code with Perfect Module Reconstruction

SafeCoder: A machine-learning-based encoding system to embed safety identification information into QR codes

Visual secret sharing (VSS) scheme can share the secret image with several shares. Shares are performed by the decoding operation to restore the secret image. VSS scheme is mainly used for the secure transmission of images. Quick response (QR) code is often used by people on the Internet. It can be encrypted by the VSS scheme to enhance the security of its transmission. The share is meaningless that will arouse the suspicion of the attacker. The security of the VSS scheme is decreased. This paper proposes a novel VSS scheme for the QR code with meaningful images to solve this problem. Two continue tone images are converted to halftone images. The halftone image is modified to generate the share. Every share is meaningful, not meaningless. Two shares are performed the decoding operation to restore the secret QR code. The restored QR code can be correctly decoded by the general decoder. Experimental results prove that the proposed scheme is feasible.

Quick Response (QR) Code is extensively used due to its advantages in fast readability as well as large capacity. However, when using QR codes, users may suffer from loss of private information because of peeping and scanning by unauthorized attackers. In this paper, we propose a novel algorithm to hide and protect the QR code based on multichannel visual masking. With our algorithm, the appearance of the QR code is dramatically changed while it maintains the original secret information. Unauthorized users can not extract any information from the protected QR code with the standard QR code reader. For authorized users, we design a truth table based decoder that works with the standard QR code reader. Extensive experiments are performed to evaluate the robustness and effectiveness of our method. The codes of this paper are published at https://github.com/JiaheZhang/Protection- QR-Code-MVM.

Quick Response (QR) codes are popular and widespread in real-world applications, and appearance is an interesting and valuable issue. To improve the black and white checkered appearance of QR codes, many designers and researchers have investigated combining QR codes with images to create a new QR style with a visual impression. Unitag is the most common manner, which focuses on a small pattern (such as a logo or a symbol) overlaid on top of the QR code to create an embellished visual image. Cox proposed QArt approach that blend binary image with QR code to improve the semblance. Based on Cox's literature, Chu et al. proposed a halftone QR code to enhance the visual fusion of QR codes. This review will analyze and compare the advantages and disadvantages of these methods in binary QR image fusion techniques. These suggestions can be considered in the related binary QR image design research for future design and user requirements.

Quick-response (QR) code technique is combined with ghost imaging (GI) to recover original information with high quality. An image is first transformed into a QR code. Then the QR code is treated as an input image in the input plane of a ghost imaging setup. After measurements, traditional correlation algorithm of ghost imaging is utilized to reconstruct an image (QR code form) with low quality. With this low-quality image as an initial guess, a Gerchberg-Saxton-like algorithm is used to improve its contrast, which is actually a post processing. Taking advantage of high error correction capability of QR code, original information can be recovered with high quality. Compared to the previous method, our method can obtain a high-quality image with comparatively fewer measurements, which means that the time-consuming postprocessing procedure can be avoided to some extent. In addition, for conventional ghost imaging, the larger the image size is, the more measurements are needed. However, for our method, images with different sizes can be converted into QR code with the same small size by using a QR generator. Hence, for the larger-size images, the time required to recover original information with high quality will be dramatically reduced. Our method makes it easy to recover a color image in a ghost imaging setup, because it is not necessary to divide the color image into three channels and respectively recover them.

Visual secret sharing (VSS) is one of the cryptographic techniques of Image secret sharing scheme (ISSS) that performs encoding of secret message image (text or picture) into noise like black and white images, which are called as shares. Shares are stacked together and secret message image is decoded using human visual system. One of the major drawbacks of this scheme is its poor contrast of the recovered image, which improves if computational device is available while decoding. In this paper, we propose to improve poor contrast of classical VSS schemes for text or alphanumeric secret messages and low entropy images. Initially, stacked image is binarized using dynamic threshold value. A mathematical morphological operation is applied on the stacked image to enhance contrast of the reconstructed image. Moreover, a method is proposed that allows the size of the structuring element to change according to the contrast and the size of a stacked image. We perform experiments for different types of VSS schemes, different share patterns, different share types (rectangle and circle), and low entropy images. Experimental results demonstrate the efficacy of the proposed scheme.

Useful feedback and evaluation are critical to a medical trainee's development. While most academic physicians understand that giving feedback to learners is essential, many do not consider the components of feedback to be truly useful, and there are barriers to implementation. We sought to use a quick reader (QR) system to solicit feedback for trainees in two pediatric subspecialties (pediatric critical care and neonatal-perinatal medicine) at one institution to increase the quality and quantity of feedback received. New valuations were modified from the existing evaluations and imported into online systems with QR code capability. Each fellow was given a QR code linking to evaluations and encouraged to solicit feedback and evaluations in a variety of clinical settings and scenarios. Evaluation numbers and quality of evaluations were assessed and compared both pre- and post-intervention. There were increases in the number of evaluations completed for both the pediatric critical care fellows and the neonatal-perinatal medicine fellows. There was no overall change in the quality of written evaluations received. Satisfaction with the evaluation system improved for both faculty and fellows of both training programs. In our critical care units, we were successfully able to implement a QR code-driven evaluation for our fellows that improved access for the faculty and offered the ability of the learner to solicit evaluations, without compromising the number or quality of evaluations. What's new: Quick reader (QR) codes can be used by learners to solicit evaluations and feedback from faculty. They can increase the quantity of written evaluations received without affecting their quality.

Abstract: In this modern world, due to the excessive availability of the Internet, it is extremely easy for people to communicate and share multimedia contents with each other. Moreover, Online Transactions has also been widely developed, in which secure means of data transfer play the major role. At the same time, secure transfer of personal and copyrighted data has become a critical issue. Visual cryptography (VC) is a useful tool for securing data (i.e. images, texts) that contain sensitive information. As a subset of secret sharing, VC has got importance for its security mechanism, which takes into account both image processing and cryptography. To achieve this goal, we manipulate quick response (QR) code as a container. QR codes generated by a certain system can carry its ordinary message in addition to the secure data. Anyone can read the message, but the secure data can only be obtained using a secret key. In this paper, a specified field of Mathematics, Number Theory is implemented in the concepts of VC for the secure online transactions which is achieved using QR codes.

Pixel expansion is a common drawback of traditional (2,2) visual secret sharing (VSS), unexpanded shares can decrease the bandwidth and save storage. In the literature, we introduce a novel (2,2) VSS scheme, that solved the pixel expansion and visual quality is almost equal with traditional (2,2) VSS. Our scheme not only can apply to (2,2) VSS, but also to (k, k) VSS. At last, analyse and experiment are conducted to evaluate the efficiency of the proposed method.

The secret sharing (SS) scheme is a cryptosystem which encrypts a secret into multiple pieces, called shares, so that only qualified combination of shares can be employed to recover the secret. The visual secret sharing (VSS) scheme is an example of SS schemes whose decryption can be performed by a human without any numerical computations. This paper is an attempt to modify the structural similarity (SSIM) index so that the modified one can measure both the structural and tonal similarities simultaneously and then to employ the modified index to give an optimization-based halftoning suitable for the encryption of VSS schemes.

In Visual Cryptography Schemes (VCSs), for message n transparencies are generated, such that the original message is visible if any k of them are stacked. VCS especially for large values of k and n, the pixel expansion’s reduction and enhancement of the recovered images’ display quality continue to be critical issues. In addition to this, it is challenging to develop a practical and systematic approach to threshold VCSs. An optimization-based pixel-expansion-free threshold VCSs approach has been proposed for binary secret images’ encryption. Along with contrast, blackness is also treated as a performance metric for assessing the recovered images’ display quality. An ideally secure technique for a secret image’s protection through its partition into shadow images (known as shadows) is the Visual Secret Sharing (VSS) scheme. Acquirement of a smaller shadow size or a higher contrast is the VSS schemes’ latest focus. The white pixels’ frequency has been utilized to demonstrate the recovered image’s contrast in this work. While the Probabilistic VSS (ProbVSS) scheme is non-expansible, it can also be readily deployed depending upon the traditional VSS scheme. Initially, this work has defined the problem as a mathematical optimization model such that, while contingent on blackness and density-balance constraints, there is the maximization of the recovered images’ contrast. Afterward, an algorithm dependent on the Tabu Search (TS) is devised in this work for this problem’s resolution. Multiple complicated combinatorial problems have been successfully resolved with the powerful TS algorithm. Moreover, this work has attempted to bolster the contrast through the density-balance constraint’s slight relaxation. Compared to the older techniques, the proposed optimization-based approach is superior regarding the recovered images’ display quality and the pixel expansion factor from the experimental outcomes.

Visual Secret Sharing (VSS) schemes address the security concerns of digital images. Rotational VSS schemes are unique in that the shares stacked with the specific rotated shares reveal the secret images. However, these schemes iteratively process huge pixels in sequence. We propose a GPGPU based rotational (2, 3) VSS scheme which leverages concurrency inherent in the traditional rotational schemes. The proposed scheme also makes use of contemporary hardware resources efficiently. The reduction in the memory band-width demand and increased data transfer speed further accelerates the speedup of this scheme. A significant improvement in performance with an efficient resource utilization is observed.

Visual secret sharing (VSS) has attracted considerable attention to scientists and engineers as another branch alongside conventional cryptography to protect the sensitive visual information from several rapacious behaviors. In the literature, there are a number of several techniques used to protect the visual information, among which traditional VSS and random grid (RG)-based VSS are the primary branches. In this letter, we show, by examples, the two means are equal. In addition, the color representation of traditional VSS and RG-based VSS found it different from digital applications like images. Based on the given examples, it is demonstrated that the color representation of the two means can be the same and confirm with digital processing applications.

Secret sharing is an information security technique where a dealer divides a secret into a collection of shares and distributes these to members of a group. The secret will only be revealed when a predefined number of group members cooperate to recover the secret. The purpose of this study is to investigate a method of distributing shares by embedding them into cover Quick Response (QR) codes in a secure manner using cryptographic keys. The advantage of this approach is that the shares can be disseminated over public channels, as anyone who scans the QR codes will only obtain public information. Only authorized individuals who are in possession of the required keys will be able to recover the shares. This also means that when group members cooperate to recover a secret, the group can determine the presence of an illegitimate participant if the person does not produce a valid share. This study proposes a protocol for accomplishing this and discusses the underlying security of the protocol.

With the rapid growth of data transmission and visual encryption technologies, Visual Secret Sharing (VSS) has become an important technique for image-based information protection. However, many existing VSS schemes remain vulnerable to dishonest participants who attempt to recover secret images through unauthorized stacking or manipulation of shares. To address this issue, this paper proposes a dishonest-participant-resistant VSS scheme based on linearly polarized shares and Probability Distribution Trees (PDTs). The proposed method embeds both secret and fake images into polarized shares, such that any unauthorized stacking of ordinary shares produces a visually plausible fake image or random noise, while only stacking that includes the master share under a predefined optical ordering reveals the true secret image. Binary image binarization and probability-guided polarization assignment are employed to improve computational efficiency and increase uncertainty against adaptive attacks. In addition to visual inspection and contrast analysis, peak signal-to-noise ratio (PSNR), structural similarity index (SSIM), and visual information fidelity (VIF) are used as complementary metrics to distinguish authorized reconstructions from unauthorized and partial ones. Experimental results show that authorized reconstructions achieve high visual fidelity and perceptual recognizability, whereas unauthorized and partial reconstructions yield significantly degraded or misleading outputs, demonstrating effective suppression of information leakage and strong resistance against dishonest behavior. Consequently, the proposed scheme enhances security and practical usability compared with existing polarization-based VSS approaches.