Speckle visual cryptography for credential authentication

Visual cryptography encodes a secret binary image (SI) into n shares of random binary patterns. If the shares are xeroxed onto transparencies, the secret image can be visually decoded by superimposing a qualified subset of transparencies, but no secret information can be obtained from the superposition of a forbidden subset. The binary patterns of the n shares, however, have no visual meaning and hinder the objectives of visual cryptography. Extended visual cryptography [1] was proposed recently to construct meaningful binary images as shares using hypergraph colourings, but the visual quality is poor. In this paper, a novel technique named halftone visual cryptography is proposed to achieve visual cryptography via halftoning. Based on the blue-noise dithering principles, the proposed method utilizes the void and cluster algorithm [2] to encode a secret binary image into n halftone shares (images) carrying significant visual information. The simulation shows that the visual quality of the obtained halftone shares are observably better than that attained by any available visual cryptography method known to date.

Visual cryptography is a cryptographic technique which allows visual information to be encrypted in such a way that the decryption can be performed by the human visual system, without the aid of computers. This paper proposes a schema of information hiding within the method of visual cryptography. The gray image is changed into two halftone images via the different dither matrixes respectively, and the secret binary pixels are encoded into shares. The secret information can be restored by stacking the different shared halftone images together. Simulation results show that the secret binary image can be decoded efficiently.

The evolution of technologies has started for increasing the security level of data. Developer and users should understand that there is no perfect solution for a secured password and it has its own way of encryption and decryption. Passwords are generated temporarily and they may be cracked easily. Human are having their own specific identity which is unique. Biometric is a feature used to identify a particular person by its DNA structure, finger print or tongue. On the other hand this feature need to be secure from wrong hands because it may be misused by any attacker. Therefore, this paper proposing a model which is consisting combination of Visual Cryptography and Steganography with the association of QR codes. Here, we are using Visual Cryptography for creating two shares in which one of the share will be rotated in a clock wise direction about 180 degree & other about 270 degree and then we are implementing Steganography by using two's complement on both the share image. After the transformation of shares into steganoimages, we are converting one of the steganoimage into a QR code which will be kept secret with the user. During the verification time, the QR code will be required for the authentication of user.

In today's world, technologies are developing at a rapid pace. It is very difficult to imagine a sphere of human life where digital data is not used, for example, banking operations, distance learning, utility payments, online messaging have become commonplace for us. However, on the other hand, the question arose of how to ensure the reliability and confidentiality of this data. One of the methods was authentication when entering the system, that is, entering a login and password to identify the user. To date, this method is not reliable and quite vulnerable, because most users have started using the same passwords for login, or simply ignore their reliability and use rather primitive ones. As a result of such actions, more and more confidential user data is at risk of being acquired by unauthorized criminals. The idea to develop a two-factor authentication system using a QR code arose as a result of the urgency of this problem and the imperfection of existing software products. The basis will be the generation of a unique code that will be available only for a short period of time, which will be enough for the user to enter the system. This technology will allow dynamically changing the set of numbers required for authentication. If an attacker takes possession of it, he will not be able to use it, because it will change in the system in a fairly quick period of time. The article discusses the implementation of the two-factor authentication algorithm using a QR code, which has a simple appearance, but can store a large amount of data. Also, regardless of how much information the QR code contains, the data is displayed immediately after reading it. This provides an increased level of protection when the user enters the system and prevents unauthorized access to confidential data by cybercriminals. An approach using TOTP (Time-based One-time password) is also proposed, which will generate a one-time code based on a secret key. The main feature is the use of time as one of the parameters to generate a dynamic 6-digit password required for logging into the system. Also, its generation will be carried out automatically every 30 seconds, thus creating conditions for making its theft and unauthorized use impossible.

<p>Visual cryptography (VC) has emerged as a pivotal solution for secure information transmission, leveraging its unique capability to encrypt images in a user-friendly and accessible manner. This survey paper provides an in-depth analysis of various VC methods, highlighting their distinct encryption and decryption techniques, applicability, and security levels. The study delves into the technical specifications of each VC type, offering insights into secret image formats, the number of secret images used, types of shares, pixel expansion, and complexity. Significant attention is given to the practical applications of VC, ranging from secure document verification and anti-counterfeiting measures to digital watermarking and online data protection. The paper also identifies key challenges in the field, such as image quality retention post-decryption, computational efficiency, and scalability. Future prospects of VC are explored, particularly its potential integration with emerging technologies like AI and blockchain. This survey aims to provide a comprehensive understanding of VC’s current state, its diverse applications, and the future possibilities, making it a valuable resource for researchers and practitioners in the field of data security and cryptography.</p>

Dependence of the individuals on the Internet for performing the several actions require secure data communication. Thus, the reliable data communication improves the confidentiality. As, enhanced security leads to reliable and faster communication. To improve the reliability and confidentiality, there is dire need of fully secured authentication method. There are several methods of password protections were introduced to protect the confidentiality and reliability. Most of the existing methods are based on alphanumeric approaches, but few methods provide the dual authentication process. In this paper, we introduce improved graphical password authentication using Twofish Encryption and Visual Cryptography (TEVC) method. Our proposed TEVC is unpredictably organized as predicting the correct graphical password and arranging its particles in the proper order is harder as compared to traditional alphanumeric password system. TEVC is tested by using JAVA platform. Based on the testing results, we confirm that proposed TEVC provides secure authentication. TEVC encryption algorithm detected as more prudent and possessing lower time complexity as compared to other known existing algorithms message code confirmation and fingerprint scan with password.

Background. Ultra-Reliable Low Latency Communication (URLLC) as a service offered by fifth and sixth generation (5G/6G) wireless systems is a technological response to the needs of various mission-critical applications that require reliable data transmission with low latency. These applications also include Intelligent Transportation Systems services, which, among other things, provide connectivity and autonomous vehicle control. The combination of high reliability and low latency requirements in URLLC usage scenarios creates a security problem for URLLC data transmission that cannot be solved using conventional complex cryptographic methods based on a secret key. The article discusses in detail the approach to using physical layer security mechanisms (physical layer security - PLS) as a powerful alternative to classical cryptographic security methods for URLLC, and also proposes the application of the wire-tap channel concept in URLLC with an analysis of the efficiency that can be achieved for physical layer security. Objective. The aim of the article is to provide an overview of information security solutions in URLLC usage scenarios, as well as to propose a constructive method for information protection for reliable data transmission with low latency without the use of cryptographic mechanisms based on a secret key. Methods. Theoretical research in the field of the branch channel concept was used to create solutions that allow data protection with information-theoretic stability in URLLC usage scenarios for providing IoT, connected car and autonomous driving services. Results. The article examines in detail the data security issues in ultra-reliable low latency communication (URLLC) as a service offered by fifth and sixth generation (5G/6G) wireless systems. It is determined that URLLC is a technological response to the needs of various critical applications that require reliable signal transmission with low latency, and among these applications are Intelligent Transportation Systems services, which, among other things, provide connectivity and autonomous vehicle control. It is shown that the combination of high reliability and low latency requirements in URLLC scenarios creates a security problem for URLLC data transmission that cannot be solved using conventional complex cryptographic methods based on a secret key. The feasibility of using physical layer security mechanisms (PLS) as a powerful alternative to classical cryptographic security methods for URLLC is substantiated. The approach to applying the concept of a wire-tap channel in URLLC is considered in detail, as well as the results that can be achieved for physical layer security, and the influence of code parameters for probabilistic cryptographic transformations in accordance with the concept of a wire-tap channel on PLS URLLC. Estimates of the effectiveness of PLS URLLC for finite block length codes are provided. Conclusions. An effective way to ensure data security for ultra-reliable low-latency physical layer link (PLS URLLC) of fifth-generation 5G wireless systems in the field of connected cars and vehicles of 4-5 levels of automation can be approaches based on the concept of a tapped channel ("wire-tap channel").

Steganography is the art of hiding secret data in a medium whereas visual-cryptography is a cryptographic technique where a full image is encrypted. The security of image steganography depends on the secret key set which is used for embedding the secret image. If the secret key is exposed, the secret image can be retrieved. To solve this security issue we propose a new type of steganography method using visual cryptography. In this method, text and image are used as a secret message and image for the cover object. 24-bit RGB color images are used as both secret and cover images. In this method, we use a new image namely share1 which converts a secret image to a totally different image called share2 image. Typically, knowing the extraction method, people can retrieve the secret message easily. A pseudorandomly generated image is used as a key for visual encryption and this ensures the extra layer of security. By this proposed method, we ensure more secured image steganography.

Traditional k out of n visual cryptography scheme has been proposed to encrypt single secret image into n shares where only k or more shares can decode the secret image. Many existing schemes on visual cryptography are restricted to consider only binary images as secret which are not appropriate for many important applications. Store-and-Forward telemedicine is one such application where medical images are transmitted from one site to another via electronic medium to analyze the patient's clinical health status. The main objective of Store-and-Forward telemedicine is to provide remote clinical services via two-way communication between the patient and the healthcare provider using electronic medical image, audio and video means. In this paper, a new XOR based Continuous-tone Multi Secret Sharing scheme suitable for store-and-forward telemedicine is proposed to securely transmit the medical images. It also eliminates basic security constraints of VC like pixel expansion in shares/recovered secret images, random pattern of shares, explicit codebook requirement, lossy recovery of secret and limitation on number of secret and shares. Proposed approach is n out of n multi secret sharing scheme which is able to transmit n secret images simultaneously. All secrets could be revealed only after some computations with all n shares and one master share. Master share has been created with the secret key at encoding phase and it can be regenerated at the time of decoding using same secret key. Here all shares are meaningful in continuous-tone which may provide confidentiality to medical images during transmission. Proposed approach not only preserves all basic characteristics of traditional VC but also increases the capacity of secret image sharing. From the experiments we found that irrespective of visible contents of the shares, the probability of getting back the pixel values of respective original secret images at the receiver end is very high.

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.

기존의 키 교환 프로토콜은 암호학적 방법들을 사용하여 비밀 키를 전달해왔지만, 공격자들로 하여금 다양한 공격을 받아왔었다. 이를 해결하기 위해 본 논문에서는 스테가노그라피 기법을 이용한 키 교환 프로토콜을 제안하였다. 스테가노그라피 기법은 이미지, 문서, 동영상, MP3 파일 등에 비밀 정보를 숨겨 공격자가 비밀 정보가 전달되고 있다는 것을 모르게 하는 방법으로 비밀 키를 공격자의 의심을 받지 않고 효율적으로 전달할 수 있다. 또한, 최근에 많이 사용되고 있는 2차원 바코드인 QR 코드를 비밀 키가 삽입되는 이미지로 사용하여 공격자가 QR 코드를 스캔하여도 QR코드 생성 시 사용되었던 URL로 접속하게 되며 QR 코드에 비밀 키가 삽입된 것을 인식하지 못하게 한다. 실험을 통해서 기존의 스테가노그라피에서 사용되었던 이미지와 QR코드의 이미지의 변형 정도를 측정하여 QR 코드 이미지를 사용했을 때 효율성을 검증해본다.

Visual cryptography (VC) is a powerful technique with high security and requires no PC or device to reconstruct the secret information. Progressive visual cryptography (PVC) is a variation of the VC scheme in which the quality of the reconstructed image is improved by increasing the number of shared images. The previous study focused directly on maximizing the value of the quality in the completely reconstructed image; thus, there is a difference in the quality of the shared images. In this paper, we focus on the aforementioned issue and propose a new approach based on inductive reasoning. Our basic idea is to maximize the quality of the reconstructed images each time the number of shared images increases. We call this method the bottom-up approach. Moreover, hitherto, PVC has been evaluated based on the value of relative difference or by sight. Such evaluation methods are only subjective or difficult to execute without the knowledge of basis matrices. In addition, PVC users cannot easily confirm the effectiveness of their shared images. In this paper, we propose a new information-theoretic evaluation method for PVC, which only uses shared images, to solve the aforementioned problems. Our proposed method can objectively and quantitatively evaluate PVC based on the numerical value, and PVC users can easily confirm the effectiveness of their shared images.

In this paper, we use an authentication system that combines Biometrics, Visual cryptography and One-Time password (OTP). We propose a basis matrix construction method for generating shares in visual cryptography technique. Generated shares are in mutually orthogonal groups so that only shares from the same group can reveal the original image. The system provides the user a share of the biometric data and keeps the other share in the server itself. The security of our scheme is based on biometric verification using visual cryptography and hash of a OTP. Therefore, the scheme is appropriate to be used in applications such as smart card and device authentication systems.

With the rapid development of computer technology, information security has attracted more and more attention. It is not only related to the information and property security of individuals and enterprises, but also to the security and social stability of a country. Identity authentication is the first line of defense in information security. In authentication systems, response time and security are the most important factors. An optical authentication technology based on compressive ghost imaging with QR codes is proposed in this paper. The scheme can be authenticated with a small number of samples. Therefore, the response time of the algorithm is short. At the same time, the algorithm can resist certain noise attacks, so it offers good security.

Biometric Cryptography is the biometric tokenization used for authentication with public-key infrastructure (PKI). In particular, biometric cryptography provides the convenience of authentication via fingerprint, face, eye, voice, palm, etc. - with none of the risks posed by having the biometrics take the form of a shared secret. With comfort, biometric verification gives more security than as it were conventional cryptography-based confirmation. Since biometric highlights of each human being are distinctive from each other, that makes it difficult to get to in an unauthorized way and it jams the privacy at the time of verification since there's no plausibility of snooping. In this manner, these days the utilization of biometric-based confirmation has expanded and utilized in versatile, portable workstation, and numerous other gadgets are utilizing biometric-based verification and biometric information stored in biometric gadgets and programmers are exceptionally shrewd they can render biometric information, can take it, and not at all like username or password biometric information can not alter, due to unique feature of biometrics. It implies, compromising biometric information will be until the end of life, and programmers can take advantage of it, so the security of biometric information is a vital issue. This paper gives some idea about cryptography methods that are capable to secure biometric data and we have presented four cryptography methods which are Biometric Encryption, Blockchain, Cancelable biometrics, and Visual cryptography. This paper also provides some challenges, issues in biometric, and future direction.