Wen-Pinn Fang

Friendly progressive visual secret sharing

This study presents a new method to achieve progressive image sharing. This new method simplifies the management of multi-secret sharing. The proposed method has all the advantages of traditional visual sharing combined with visual cryptography, namely fast decoding, lossless and prevention of secret disclosure without collecting enough shares. Additionally, it can easily distinguish the group to which the share belongs through friendly meaningful shares.

Visual cryptography with extra ability of hiding confidential data

We present a two-in-one visual cryptography (VC) scheme that not only shares an image of moderate confidentiality between two noisy transparencies, but also hides in these two transparencies a more confidential text file describing the image. None of the transparencies alone can reveal anything about the image or text. Later, people can view the image by simply stacking the two transparencies; on the other hand, after certain simple computations, the more confidential text data can also be extracted. We also introduce an alternative version in which the decoding of both the image and text requires no computer.

Progressive viewing and sharing of sensitive images

The paper proposes a progressive viewing method useful in sharing a sensitive image. As in visual cryptography, this method characterizes its ability to recover the image by stacking transparencies without any computation. However, the method balances the sensitivity and the daily-processing convenience of the image.

Visual Cryptography in reversible style

We proposed in this paper a brand new type of visual cryptography (VC), namely, the VC in reversible style. For any two given secret images, two corresponding transparencies S1 and S2, also known as shares, can be produced. Both transparencies look noisy. However, if we stack the front views of both transparencies, then the first secret image is unveiled. On the other hand, if we stack the front view of S1 with the back view (the turn-over) of S2, then the second secret image is unveiled.

Prevention of cheating in visual cryptography by using coherent patterns

A new VC scheme with cheating-prevention ability is proposed.It reveals solid pattern with moderate-scale on partial-superimposed image.The proposed method verifies shares without any additional authentication shares.The proposed method endows conventional VC with cheating-prevention ability. This paper proposes a simple method for establishing a visual cryptographic (VC) scheme with the ability to prevent cheating. Given the n base-shares generated in a conventional (t,n), 2≤t≤n, VC scheme, an authentication pattern stamping process was designed to encode the n base-shares to get n verifiable shares that exhibit the following properties: (1) knowledge of less than t verifiable-shares gets no secret information, (2) the secret can be revealed by completely superimposing t or more verifiable-shares, and (3) the authentication pattern can be revealed by partially superimposing any pair of verifiable-shares. Theoretical proof and computer simulation for the proposed method are provided. The proposed method has smaller pixel expansion than previous cheating prevention VC schemes, and the verification process is fulfilled without resorting to any additional dedicated verification share. It can be attached easily to any reported VC scheme to endow legitimate users with the capability of detecting faked shares provided by malicious participants.

Universal share for the sharing of multiple images

Abstract To share numerous grey‐valued images (or numerous color‐valued images), this study presents a system with a universal share. A company organizer can use this universal share to attend the recovery meeting of any shared image. No storage space is wasted; i.e. for each shared image, the total storage space occupied by all generated shares (including the universal share) is identical to the image size.

An novel two layer user identification method

This paper proposed a two layer authorization mechanism, including traditional password system and rhythm recognition. The whole system includes two phases: preprocessing and usual operation for users. In preprocessing phase, users type password in a specific rhythm in order to record and analyse the characteristics of behaviour of users. In the second phase, how to verify a user in usual operation is described. The main recognition procedure consists of two stages: password check and rhythm recognition separately. User shall input correct password in correct rhythm. Here rhythm is a sequence of beats with various time intervals in between. The beat is in correspondent with every key down event. In the authorization procedure, system will check ID and password first. At the same time, system will record all time intervals of key down events. After recording all time intervals, system compares the characteristics of the resultant rhythm with that in user database. If the distance is under some threshold of error tolerance, user will be authorized. Otherwise, entering system will not be approved. The proposed two layer authorization method successfully enhances the security and efficiency of password system. The proposed distance calculation enables our calculation to be much cost effective than that of other rhythm recognition methods.

An Intelligent Hand Gesture Extraction and Recognition System for Home Care Application

This paper proposes a hand gesture extraction method. Based on motion detection and feature recognition, an intelligent hand gesture extraction method is achieved. It is possible to apply in most of homecare system, especially those patients without the ability to speak well. the system is also can apply in intelligent commercial devices control, such as television and light.

Offline QR Code Authorization Based on Visual Cryptography

It is popular to use mobile phone daily in modern life. Among the numerous applications provided by mobile phone, barcode utility is one of the important branches. Many companies supply barcode tools for mobile phones. For example, Googles mobile Android operating system supports QR codes by natively including the barcode scanner in some models, and the browser supports URI redirection function which allows QR codes to send metadata to the applications on the device. After investigated the supplied applications on mobile devices, most of the products exhibit information accessible to every user. Differ from the traditional applications of QR Code. This paper proposes an offline authentication mechanism for QR codes. Based on the technology of visual cryptography, it is possible to check the identity accessing to the QR codes and to control the permission to the protected data.

Parallel Processing for Secret Image Sharing

Secret image sharing is a method to transmit and store an image safely. The security of secret image sharing is based on the fact that the values are operated in the finite field and the number of pixels is high enough to ensure security. However, the time complexity to encode and decode a secret image is not acceptable in real-time application. There are some papers discussing how to upgrade the efficiency of encoding phase while few papers exploring how to decrease the decoding phase time. This paper proposes a method to achieve to speed up decoding phase by parallel processing.