Quantum e-commerce: A comparative study of possible protocols for online shopping and other tasks related to e-commerce

A set of quantum protocols for online shopping is proposed and analyzed to establish that it is possible to perform secure online shopping using different types of quantum resources. Specifically, a single photon based, a Bell state based and two 3-qubit entangled state based quantum online shopping schemes are proposed. The Bell state based scheme, being a completely orthogonal state based protocol, is fundamentally different from the earlier proposed schemes which were based on conjugate coding. One of the 3-qubit entangled state based scheme is build on the principle of entanglement swapping which enables us to accomplish the task without transmission of the message encoded qubits through the channel. Possible ways of generalizing the entangled state based schemes proposed here to the schemes which use multiqubit entangled states is also discussed. Further, all the proposed protocols are shown to be free from the limitations of the recently proposed protocol of Huang et al. (Quantum Inf. Process. 14, 2211-2225, 2015) which allows the buyer (Alice) to change her order at a later time (after initially placing the order and getting it authenticated by the controller). The proposed schemes are also compared with the existing schemes using qubit efficiency.Comment: It's shown that quantum e-commerce is not a difficult task, and it can be done in various way

Synchronization of multi-carrier CDMA signals and security on internet.

by Yooh Ji Heng.Thesis (M.Phil.)--Chinese University of Hong Kong, 1996.Includes bibliographical references (leaves 119-128).Appendix in Chinese.Chapter I --- Synchronization of Multi-carrier CDMA Signals --- p.1Chapter 1 --- Introduction --- p.2Chapter 1.1 --- Spread Spectrum CDMA --- p.4Chapter 1.1.1 --- Direct Sequence/SS-CDMA --- p.5Chapter 1.1.2 --- Frequency Hopping/SS-CDMA --- p.5Chapter 1.1.3 --- Pseudo-noise Sequence --- p.6Chapter 1.2 --- Synchronization for CDMA signal --- p.7Chapter 1.2.1 --- Acquisition of PN Sequence --- p.7Chapter 1.2.2 --- Phase Locked Loop --- p.8Chapter 2 --- Multi-carrier CDMA --- p.10Chapter 2.1 --- System Model --- p.11Chapter 2.2 --- Crest Factor --- p.12Chapter 2.3 --- Shapiro-Rudin Sequence --- p.14Chapter 3 --- Synchronization and Detection by Line-Fitting --- p.16Chapter 3.1 --- Unmodulated Signals --- p.16Chapter 3.2 --- Estimating the Time Shift by Line-Fitting --- p.19Chapter 3.3 --- Modulated Signals --- p.22Chapter 4 --- Matched Filter --- p.23Chapter 5 --- Performance and Conclusion --- p.27Chapter 5.1 --- Line Fitting Algorithm --- p.27Chapter 5.2 --- Matched Filter --- p.28Chapter 5.3 --- Conclusion --- p.30Chapter II --- Security on Internet --- p.31Chapter 6 --- Introduction --- p.32Chapter 6.1 --- Introduction to Cryptography --- p.32Chapter 6.1.1 --- Classical Cryptography --- p.33Chapter 6.1.2 --- Cryptanalysis --- p.35Chapter 6.2 --- Introduction to Internet Security --- p.35Chapter 6.2.1 --- The Origin of Internet --- p.35Chapter 6.2.2 --- Internet Security --- p.36Chapter 6.2.3 --- Internet Commerce --- p.37Chapter 7 --- Elementary Number Theory --- p.39Chapter 7.1 --- Finite Field Theory --- p.39Chapter 7.1.1 --- Euclidean Algorithm --- p.40Chapter 7.1.2 --- Chinese Remainder Theorem --- p.40Chapter 7.1.3 --- Modular Exponentiation --- p.41Chapter 7.2 --- One-way Hashing Function --- p.42Chapter 7.2.1 --- MD2 --- p.43Chapter 7.2.2 --- MD5 --- p.43Chapter 7.3 --- Prime Number --- p.44Chapter 7.3.1 --- Listing of Prime Number --- p.45Chapter 7.3.2 --- Primality Testing --- p.45Chapter 7.4 --- Random/Pseudo-Random Number --- p.47Chapter 7.4.1 --- Examples of Random Number Generator --- p.49Chapter 8 --- Private Key and Public Key Cryptography --- p.51Chapter 8.1 --- Block Ciphers --- p.51Chapter 8.1.1 --- Data Encryption Standard (DES) --- p.52Chapter 8.1.2 --- International Data Encryption Algorithm (IDEA) --- p.54Chapter 8.1.3 --- RC5 --- p.55Chapter 8.2 --- Stream Ciphers --- p.56Chapter 8.2.1 --- RC2 and RC4 --- p.57Chapter 8.3 --- Public Key Cryptosystem --- p.58Chapter 8.3.1 --- Diffie-Hellman --- p.60Chapter 8.3.2 --- Knapsack Algorithm --- p.60Chapter 8.3.3 --- RSA --- p.62Chapter 8.3.4 --- Elliptic Curve Cryptosystem --- p.63Chapter 8.3.5 --- Public Key vs. Private Key Cryptosystem --- p.64Chapter 8.4 --- Digital Signature --- p.65Chapter 8.4.1 --- ElGamal Signature Scheme --- p.66Chapter 8.4.2 --- Digital Signature Standard (DSS) --- p.67Chapter 8.5 --- Cryptanalysis to Current Cryptosystems --- p.68Chapter 8.5.1 --- Differential Cryptanalysis --- p.68Chapter 8.5.2 --- An Attack to RC4 in Netscapel.l --- p.69Chapter 8.5.3 --- "An Timing Attack to Diffie-Hellman, RSA" --- p.71Chapter 9 --- Network Security and Electronic Commerce --- p.73Chapter 9.1 --- Network Security --- p.73Chapter 9.1.1 --- Password --- p.73Chapter 9.1.2 --- Network Firewalls --- p.76Chapter 9.2 --- Implementation for Network Security --- p.79Chapter 9.2.1 --- Kerberos --- p.79Chapter 9.2.2 --- Privacy-Enhanced Mail (PEM) --- p.80Chapter 9.2.3 --- Pretty Good Privacy (PGP) --- p.82Chapter 9.3 --- Internet Commerce --- p.83Chapter 9.3.1 --- Electronic Cash --- p.85Chapter 9.4 --- Internet Browsers --- p.87Chapter 9.4.1 --- Secure NCSA Mosaic --- p.87Chapter 9.4.2 --- Netscape Navigator --- p.89Chapter 9.4.3 --- SunSoft HotJava --- p.91Chapter 10 --- Examples of Electronic Commerce System --- p.94Chapter 10.1 --- CyberCash --- p.95Chapter 10.2 --- DigiCash --- p.97Chapter 10.3 --- The Financial Services Technology Consortium --- p.98Chapter 10.3.1 --- Electronic Check Project --- p.99Chapter 10.3.2 --- Electronic Commerce Project --- p.101Chapter 10.4 --- FirstVirtual --- p.103Chapter 10.5 --- Mondex --- p.104Chapter 10.6 --- NetBill --- p.106Chapter 10.7 --- NetCash --- p.108Chapter 10.8 --- NetCheque --- p.111Chapter 11 --- Conclusion --- p.113Chapter A --- An Essay on Chinese Remainder Theorem and RSA --- p.115Bibliography --- p.11

Quantum cryptography: key distribution and beyond

Uniquely among the sciences, quantum cryptography has driven both foundational research as well as practical real-life applications. We review the progress of quantum cryptography in the last decade, covering quantum key distribution and other applications.Comment: It's a review on quantum cryptography and it is not restricted to QK

Cryptography and Its Applications in Information Security

Nowadays, mankind is living in a cyber world. Modern technologies involve fast communication links between potentially billions of devices through complex networks (satellite, mobile phone, Internet, Internet of Things (IoT), etc.). The main concern posed by these entangled complex networks is their protection against passive and active attacks that could compromise public security (sabotage, espionage, cyber-terrorism) and privacy. This Special Issue “Cryptography and Its Applications in Information Security” addresses the range of problems related to the security of information in networks and multimedia communications and to bring together researchers, practitioners, and industrials interested by such questions. It consists of eight peer-reviewed papers, however easily understandable, that cover a range of subjects and applications related security of information

Quantum Cryptography: Key Distribution and Beyond

Uniquely among the sciences, quantum cryptography has driven both foundational research as well as practical real-life applications. We review the progress of quantum cryptography in the last decade, covering quantum key distribution and other applications.Quanta 2017; 6: 1–47

End-to-end security in active networks

Active network solutions have been proposed to many of the problems caused by the increasing heterogeneity of the Internet. These ystems allow nodes within the network to process data passing through in several ways. Allowing code from various sources to run on routers introduces numerous security concerns that have been addressed by research into safe languages, restricted execution environments, and other related areas. But little attention has been paid to an even more critical question: the effect on end-to-end security of active flow manipulation. This thesis first examines the threat model implicit in active networks. It develops a framework of security protocols in use at various layers of the networking stack, and their utility to multimedia transport and flow processing, and asks if it is reasonable to give active routers access to the plaintext of these flows. After considering the various security problem introduced, such as vulnerability to attacks on intermediaries or coercion, it concludes not. We then ask if active network systems can be built that maintain end-to-end security without seriously degrading the functionality they provide. We describe the design and analysis of three such protocols: a distributed packet filtering system that can be used to adjust multimedia bandwidth requirements and defend against denial-of-service attacks; an efficient composition of link and transport-layer reliability mechanisms that increases the performance of TCP over lossy wireless links; and a distributed watermarking servicethat can efficiently deliver media flows marked with the identity of their recipients. In all three cases, similar functionality is provided to designs that do not maintain end-to-end security. Finally, we reconsider traditional end-to-end arguments in both networking and security, and show that they have continuing importance for Internet design. Our watermarking work adds the concept of splitting trust throughout a network to that model; we suggest further applications of this idea

Design and Analysis of Opaque Signatures

Digital signatures were introduced to guarantee the authenticity and integrity of the underlying messages. A digital signature scheme comprises the key generation, the signature, and the verification algorithms. The key generation algorithm creates the signing and the verifying keys, called also the signer’s private and public keys respectively. The signature algorithm, which is run by the signer, produces a signature on the input message. Finally, the verification algorithm, run by anyone who knows the signer’s public key, checks whether a purported signature on some message is valid or not. The last property, namely the universal verification of digital signatures is undesirable in situations where the signed data is commercially or personally sensitive. Therefore, mechanisms which share most properties with digital signatures except for the universal verification were invented to respond to the aforementioned need; we call such mechanisms “opaque signatures”. In this thesis, we study the signatures where the verification cannot be achieved without the cooperation of a specific entity, namely the signer in case of undeniable signatures, or the confirmer in case of confirmer signatures; we make three main contributions. We first study the relationship between two security properties important for public key encryption, namely data privacy and key privacy. Our study is motivated by the fact that opaque signatures involve always an encryption layer that ensures their opacity. The properties required for this encryption vary according to whether we want to protect the identity (i.e. the key) of the signer or hide the validity of the signature. Therefore, it would be convenient to use existing work about the encryption scheme in order to derive one notion from the other. Next, we delve into the generic constructions of confirmer signatures from basic cryptographic primitives, e.g. digital signatures, encryption, or commitment schemes. In fact, generic constructions give easy-to-understand and easy-to-prove schemes, however, this convenience is often achieved at the expense of efficiency. In this contribution, which constitutes the core of this thesis, we first analyze the already existing constructions; our study concludes that the popular generic constructions of confirmer signatures necessitate strong security assumptions on the building blocks, which impacts negatively the efficiency of the resulting signatures. Next, we show that a small change in these constructionsmakes these assumptions drop drastically, allowing as a result constructions with instantiations that compete with the dedicated realizations of these signatures. Finally, we revisit two early undeniable signatures which were proposed with a conjectural security. We disprove the claimed security of the first scheme, and we provide a fix to it in order to achieve strong security properties. Next, we upgrade the second scheme so that it supports a iii desirable feature, and we provide a formal security treatment of the new scheme: we prove that it is secure assuming new reasonable assumptions on the underlying constituents