Low Cost and Compact Quantum Cryptography

We present the design of a novel free-space quantum cryptography system, complete with purpose-built software, that can operate in daylight conditions. The transmitter and receiver modules are built using inexpensive off-the-shelf components. Both modules are compact allowing the generation of renewed shared secrets on demand over a short range of a few metres. An analysis of the software is shown as well as results of error rates and therefore shared secret yields at varying background light levels. As the system is designed to eventually work in short-range consumer applications, we also present a use scenario where the consumer can regularly 'top up' a store of secrets for use in a variety of one-time-pad and authentication protocols.Comment: 18 pages, 9 figures, to be published in New Journal of Physic

Pseudo Random Generator Based Public Key Cryptography

Advances in communication technology have seen strong interest in digital data transmission. However, illegal data access has become more easy and prevalent in wireless and general communication networks. In order to protect the valuable data from illegal access, different kinds of cryptographic systems have been proposed. In this paper, a new integrating channel coding and cryptography design communication systems is proposed. So we use cryptography as an error detection tool. In order to preserve the advantages of encryption and to improve its disadvantages, we place the encryptor before the encoder. The hamming encoder is used to select the generator matrix to be used as a block code to form the new system .In this the security of common cryptographic primitive i.e a key stream generator based on LFSR can be strengthened by using the properties of a physical layer.So, a passive eaves dropping will experience great difficulty in cracking the LFSR based cryptography system as the computational complexity of discovering the secret key increases to large extent. The analysis indicates that the proposed design possesses the following feature. Its security is higher than the conventional one with the channel encoder only. Privacy is more due to unknown random codes. As the applied codes are unknown to a hostile user, this means that it is hardly possible to detect the message of another user. Anti-jam performance is good. It overcomes the disadvantage of Chaos based cryptography system as input data is not extended and hence bandwidth is not wasted. Moreover, the computer simulation shows that the proposed system has a good ability in error detection especially when the SNR per bit is moderate high, and the detection ability is enhanced when the increased length of Hamming code is employed

A Basic Framework for the Cryptanalysis of Digital Chaos-Based Cryptography

Chaotic cryptography is based on the properties of chaos as source of entropy. Many different schemes have been proposed to take advantage of those properties and to design new strategies to encrypt information. However, the right and efficient use of chaos in the context of cryptography requires a thorough knowledge about the dynamics of the selected chaotic system. Indeed, if the final encryption system reveals enough information about the underlying chaotic system it could be possible for a cryptanalyst to get the key, part of the key or some information somehow equivalent to the key just analyzing those dynamical properties leaked by the cryptosystem. This paper shows what those dynamical properties are and how a cryptanalyst can use them to prove the inadequacy of an encryption system for the secure exchange of information. This study is performed through the introduction of a series of mathematical tools which should be the basic framework of cryptanalysis in the context of digital chaos-based cryptography.Comment: 6 pages, 5 figure

PENGEMBANGAN SISTEM OTENTIKASI PADA SEBUAH APLIKASI YANG BERBASISKAN WEB

The purpose of this system made is point to the additional previous system that has been exited to protect maximally. The maximal protection is not guarantee what had been done but, it is aims do depend of firewall of a system. As well as the function itself. In design this system the researcher not only using the cryptography. That contains in PHP program is MD5. Basically the applying MD5 is not enough to secure an application based on web. Therefore the researcher’s Design a random system in purpose more guarantee data or password in a database. By adding a new good system, as a result it will easier to processing secure of data accurately and also guarantee secure of data itself. The result of this research is an application in which it is able directly apply that make by the programmer itself

New Designs for Friendly Visual Cryptography Scheme

NSC101-2221-E-032-047[[abstract]]Different from conventional cryptography, visual cryptography is an image cryptographic technique proposed by Naor and Shamir. It encodes a secret image into n pieces of noise-like shares. When k or more than k pieces of shares are gathered from participants, human visual system will disclose the secret image on the stacked image easily. Neither complicated mathematical computation nor any knowledge of cryptography are needed are the main advantages of visual cryptography. In this paper, we propose a new design for friendly visual cryptography scheme. The secret will be hiding into two meaningful shares. The black-appearing ratio in each block of the shares for the corresponding black (rep. white) secret pixel is the same. Therefore, it is impossible for one to disclose any information related to the secret image on each share, which achieves the goal of improving security. When shares are superimposed, the contours of the cover image will disappear on the stacked image, which will only reveal the secret image. According to our experimental results, the contrasts of the shares or the stacked images are good which can reveal the contents of the cover images and the secret image clearly.[[notice]]補正完畢[[journaltype]]國外[[ispeerreviewed]]Y[[booktype]]紙本[[countrycodes]]SG

Modular, Cost-Effective, Extensible Avionics Architecture for Secure, Mobile Communications

Current onboard communication architectures are based upon an all-in-one communications management unit. This unit and associated radio systems has regularly been designed as a one-off, proprietary system. As such, it lacks flexibility and cannot adapt easily to new technology, new communication protocols, and new communication links. This paper describes the current avionics communication architecture and provides a historical perspective of the evolution of this system. A new onboard architecture is proposed that allows full use of commercial-off-the-shelf technologies to be integrated in a modular approach thereby enabling a flexible, cost-effective and fully deployable design that can take advantage of ongoing advances in the computer, cryptography, and telecommunications industries