Search

This article argues that papermaking supported cryptanalysis's invention; that cryptology—meaning both cryptography and cryptanalysis—could not be practiced before the sustained production of paper; and that Medieval Arabic cryptology originated in tandem with algebra. Furthermore, this article posits that the regional Islamicate postal service, or thebarīd, was used to relay Medieval Arabic cryptograms and thereby shaped the substance of cryptology. These conclusions stem from examining ninth century to fourteenth century Arabic cryptology as a technology and relating Arabic cryptology to three other technological devices: papermaking in the Middle East, algebra, and thebarīd. Extant documents suggest that cryptology originated in ninth century Baghdad. This is because no cryptanalytical writings are known to exist before this period, and cryptology requires both cryptography and cryptanalysis. However, evidence of Medieval Arabic cryptology exists almost exclusively in practitioners' treatises, not in cryptograms or the working papers of cryptanalysts. To redress this barrier to historical research, I move from text to context, or from the ideas in the treatises to thinking about the technologies these ideas called for. Placing cryptological technology within the wider technological context that inspired, shaped, and confined its development suggests why cryptology originated in the Islamicate world, how Arabic cryptology may have been implemented in practice, and what enabled cryptology's start. I hope that this technological exercise encourages the study of the context in which Medieval Arabic cryptology developed, until further primary sources surface. Furthermore, I intend to demonstrate Medieval Arabic cryptology's relevance to cryptological history and Middle Eastern studies. [ABSTRACT FROM PUBLISHER]

As an important branch of quantum secure multiparty computation, quantum private comparison (QPC) has attracted more and more attention recently. In this paper, according to the quantum implementation mechanism that these protocols used, we divide these protocols into three categories: The quantum cryptography QPC, the superdense coding QPC, and the entanglement swapping QPC. And then, a more in-depth analysis on the research progress, design idea, and substantive characteristics of corresponding QPC categories is carried out, respectively. Finally, the applications of QPC and quantum secure multi-party computation issues are discussed and, in addition, three possible research mainstream directions are pointed out. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a novel geometric active contour model for color image is presented. It combines squared local contrast based alignment term about directional information of edge location as part of driving force, together with the improved geodesic active contour model containing Bays error based two-region segmentation information. And all these measures are integrated as a unified framework. Finally, an unconditionally stable and simple numerical scheme, including the narrow band and fast marching methods, is introduced for efficiently implementing this novel model. Experimental results on color image segmentation show that it can extract the contour of color images precisely and its performance is shown much better than the geodesic-aided C–V (GACV) method when directional information about edge location is supplied. [Copyright &y& Elsevier]

Abstract  The first practical identity based encryption (IBE) scheme was published by Boneh and Franklin at Crypto 2001, based on the elliptic curve pairing. Since that time, many other IBE schemes have been published. In this paper, we describe a variant of Boneh-Franklin with a tight reduction in the random oracle model. Our new scheme is quite efficient compared to existing schemes; moreover, upgrading from Boneh-Franklin to our new scheme is straightforward. [ABSTRACT FROM AUTHOR]

Abstract: Recently, Lin and Tsai and Yang et al. proposed secret image sharing schemes with steganography and authentication, which divide a secret image into the shadows and embed the produced shadows in the cover images to form the stego images so as to be transmitted to authorized recipients securely. In addition, these schemes also involve their authentication mechanisms to verify the integrity of the stego images such that the secret image can be restored correctly. Unfortunately, these schemes still have two shortcomings. One is that the weak authentication cannot well protect the integrity of the stego images, so the secret image cannot be recovered completely. The other shortcoming is that the visual quality of the stego images is not good enough. To overcome such drawbacks, in this paper, we propose a novel secret image sharing scheme combining steganography and authentication based on Chinese remainder theorem (CRT). The proposed scheme not only improves the authentication ability but also enhances the visual quality of the stego images. The experimental results show that the proposed scheme is superior to the previously existing methods. [Copyright &y& Elsevier]

In image steganography, a pixel can carry secret bits by choosing adding/subtracting one to/from the gray value. This kind of"±1 steganography" can hide a longer message than simple LSB embedding. We propose a double-layered embedding method for implementing "±1 steganography," in which binary covering codes and wet paper codes are used to hide messages in the LSB plane and the second LSB plane, respectively. We show that this method can achieve the upper bound on the embedding efficiency of"±1 steganography" when the employed binary covering codes reach the upper bound on that of LSB steganography. Applications using random and structured covering codes show that the new method outperforms previous ones and can approach the upper bound. [ABSTRACT FROM AUTHOR]

Abstract: The fundamental concern of Information Assurance today is the issue of trust. Cryptography is one of the main technical defence mechanisms in our armoury, and yet the relationship between the two has rarely been explored. This paper will look at some of the interplay between trust issues and cryptography. [Copyright &y& Elsevier]