Covert QR codes: How to hide in the crowd

This paper investigates a novel approach of distributing a hidden message via public channels. The proposed approach employs visual subterfuge to conceal secret information within a QR code. Using a QR code reader, any individual can decode the public information contained in the QR code. However, only authorized users who have the necessary credentials will be able to obtain the secret message, which is encoded in the form of a secret QR code. We call this a Covert QR (CQR) code scheme. To embed the secret information, this approach exploits the error correction mechanism inherent in the QR code structure. By using QR codes to conceal information, the proposed scheme has the advantage of reducing the likelihood of attracting the attention of potential adversaries. In addition, the information in QR codes can be scanned and decoded through the visual channel. As such, the secret information can be distributed on printed media and is not restricted to an electronic form

SBVLC:Secure Barcode-based Visible Light Communication for Smartphones

2D barcodes have enjoyed a significant penetration rate in mobile applications. This is largely due to the extremely low barrier to adoption – almost every camera-enabled smartphone can scan 2D barcodes. As an alternative to NFC technology, 2D barcodes have been increasingly used for security-sensitive mobile applications including mobile payments and personal identification. However, the security of barcode-based communication in mobile applications has not been systematically studied. Due to the visual nature, 2D barcodes are subject to eavesdropping when they are displayed on the smartphone screens. On the other hand, the fundamental design principles of 2D barcodes make it difficult to add security features. In this paper, we propose SBVLC - a secure system for barcode-based visible light communication (VLC) between smartphones. We formally analyze the security of SBVLC based on geometric models and propose physical security enhancement mechanisms for barcode communication by manipulating screen view angles and leveraging user-induced motions. We then develop three secure data exchange schemes that encode information in barcode streams. These schemes are useful in many security-sensitive mobile applications including private information sharing, secure device pairing, and contactless payment. SBVLC is evaluated through extensive experiments on both Android and iOS smartphones

Efficient (k, n) : threshold secret sharing method with cheater prevention for QR code application

To protect secret message, secret sharing technique divides it into n shares and distributes them to n involved participants. However, it is hardly to prevent a dishonest participant to cheat other by providing a fake share. To overcome this weakness, this paper presents an efficient (k, n)-threshold secret sharing approach with the functionality of cheater identification using meaningful QR codes. The secret message would be split into k pieces, and used as the coefficients of polynomial function to generate n shares. These shares would be concealed into cover QR codes based on its fault tolerance to generate meaningful QR code shares. The meaningful QR code shares are helpful to reduce the curiosity of unrelated persons when transmitted in public channel. The legitimacy of QR code share would be verified before secret reconstruction to prevent cheater in secret revealing procedure. Some experiments were done to evaluate the performance of the proposed scheme. The experimental results show that the proposed scheme is efficient, highly secure and highly robust, and it also achieves a higher embedding capacity compared to previous methods

Roadmap on optical security

Postprint (author's final draft

Printed document integrity verification using barcode

Printed documents are still relevant in our daily life and information in it must be protected from threats and attacks such as forgery, falsification or unauthorized modification. Such threats make the document lose its integrity and authenticity. There are several techniques that have been proposed and used to ensure authenticity and originality of printed documents. But some of the techniques are not suitable for public use due to its complexity, hard to obtain special materials to secure the document and expensive. This paper discuss several techniques for printed document security such as watermarking and barcode as well as the usability of two dimensional barcode in document authentication and data compression with the barcode. A conceptual solution that are simple and efficient to secure the integrity and document sender's authenticity is proposed that uses two dimensional barcode to carry integrity and authenticity information in the document. The information stored in the barcode contains digital signature that provides sender's authenticity and hash value that can ensure the integrity of the printed document

Visual secret sharing and related Works -A Review

The accelerated development of network technology and internet applications has increased the significance of protecting digital data and images from unauthorized access and manipulation. The secret image-sharing network (SIS) is a crucial technique used to protect private digital photos from illegal editing and copying. SIS can be classified into two types: single-secret sharing (SSS) and multi-secret sharing (MSS). In SSS, a single secret image is divided into multiple shares, while in MSS, multiple secret images are divided into multiple shares. Both SSS and MSS ensure that the original secret images cannot be reconstructed without the correct combination of shares. Therefore, several secret image-sharing methods have been developed depending on these two methods for example visual cryptography, steganography, discrete wavelet transform, watermarking, and threshold. All of these techniques are capable of randomly dividing the secret image into a large number of shares, each of which cannot provide any information to the intrusion team.  This study examined various visual secret-sharing schemes as unique examples of participant secret-sharing methods. Several structures that generalize and enhance VSS were also discussed in this study on covert image-sharing protocols and also this research also gives a comparative analysis of several methods based on various attributes in order to better concentrate on the future directions of the secret image. Generally speaking, the image quality generated employing developed methodologies is preferable to the image quality achieved through using the traditional visual secret-sharing methodology