1,609 research outputs found
Applications of single-qubit rotations in quantum public-key cryptography
We discuss cryptographic applications of single-qubit rotations from the
perspective of trapdoor one-way functions and public-key encryption. In
particular, we present an asymmetric cryptosystem whose security relies on
fundamental principles of quantum physics. A quantum public key is used for the
encryption of messages while decryption is possible by means of a classical
private key only. The trapdoor one-way function underlying the proposed
cryptosystem maps integer numbers to quantum states of a qubit and its
inversion can be infeasible by virtue of the Holevo's theorem.Comment: to appear in Phys. Rev.
Efficient and secure ranked multi-keyword search on encrypted cloud data
Information search and document retrieval from a remote database (e.g. cloud server) requires submitting the search terms to the database holder. However, the search terms may contain sensitive information that must be kept secret from the database holder. Moreover, the privacy concerns apply to the relevant documents retrieved by the user in the later stage since they may also contain sensitive data and reveal information about sensitive search terms. A related protocol, Private Information Retrieval (PIR), provides useful cryptographic tools to hide the queried search terms and the data retrieved from the database while returning most relevant documents to the user. In this paper, we propose a practical privacy-preserving ranked keyword search scheme based on PIR that allows multi-keyword queries with ranking capability. The proposed scheme increases the security of the keyword search scheme while still satisfying efficient computation and communication requirements. To the best of our knowledge the majority of previous works are not efficient for assumed scenario where documents are large files. Our scheme outperforms the most efficient proposals in literature in terms of time complexity by several orders of magnitude
Product Authentication Using Hash Chains and Printed QR Codes
This thesis explores the usage of simple printed tags for authenticating products. Printed tags are a cheap alternative to RFID and other tag based systems and do not require specialized equipment. Due to the simplistic nature of such printed codes, many security issues like tag impersonation, server impersonation, reader impersonation, replay attacks and denial of service present in RFID based solutions need to be handled differently. An algorithm that utilizes hash chains to secure such simple tags while still keeping cost low is discussed. The security characteristics of this scheme as well as other product authentication schemes that use RFID tags are compared. Arguments for static tags being at least as secure as RFID tags is discussed. Finally, a scheme for combining RFID authentication with static tags to achieve security throughout the supply chain is discussed
A Talk on Quantum Cryptography, or How Alice Outwits Eve
Alice and Bob wish to communicate without the archvillainess Eve
eavesdropping on their conversation. Alice, decides to take two college
courses, one in cryptography, the other in quantum mechanics. During the
courses, she discovers she can use what she has just learned to devise a
cryptographic communication system that automatically detects whether or not
Eve is up to her villainous eavesdropping. Some of the topics discussed are
Heisenberg's Uncertainty Principle, the Vernam cipher, the BB84 and B92
cryptographic protocols. The talk ends with a discussion of some of Eve's
possible eavesdropping strategies, opaque eavesdropping, translucent
eavesdropping, and translucent eavesdropping with entanglement.Comment: 31 pages, 8 figures. Revised version of a paper published in "Coding
Theory, and Cryptography: From Geheimscheimschreiber and Enigma to Quantum
Theory," (edited by David Joyner), Springer-Verlag, 1999 (pp. 144-174). To be
published with the permission of Springer-Verlag in an AMS PSAPM Short Course
volume entitled "Quantum Computation.
The Interpolating Random Spline Cryptosystem and the Chaotic-Map Public-Key Cryptosystem
The feasibility of implementing the interpolating cubic spline function as encryption and decryption transformations is presented. The encryption method can be viewed as computing a transposed polynomial. The main characteristic of the spline cryptosystem is that the domain and range of encryption are defined over real numbers, instead of the traditional integer numbers. Moreover, the spline cryptosystem can be implemented in terms of inexpensive multiplications and additions.
Using spline functions, a series of discontiguous spline segments can execute the modular arithmetic of the RSA system. The similarity of the RSA and spline functions within the integer domain is demonstrated. Furthermore, we observe that such a reformulation of RSA cryptosystem can be characterized as polynomials with random offsets between ciphertext values and plaintext values. This contrasts with the spline cryptosystems, so that a random spline system has been developed. The random spline cryptosystem is an advanced structure of spline cryptosystem. Its mathematical indeterminacy on computing keys with interpolants no more than 4 and numerical sensitivity to the random offset t( increases its utility.
This article also presents a chaotic public-key cryptosystem employing a one-dimensional difference equation as well as a quadratic difference equation. This system makes use of the El Gamal’s scheme to accomplish the encryption process. We note that breaking this system requires the identical work factor that is needed in solving discrete logarithm with the same size of moduli
Secure and Privacy-Preserving Authentication Protocols for Wireless Mesh Networks
Wireless mesh networks (WMNs) have emerged as a promising concept to meet the
challenges in next-generation wireless networks such as providing flexible,
adaptive, and reconfigurable architecture while offering cost-effective
solutions to service providers. As WMNs become an increasingly popular
replacement technology for last-mile connectivity to the home networking,
community and neighborhood networking, it is imperative to design efficient and
secure communication protocols for these networks. However, several
vulnerabilities exist in currently existing protocols for WMNs. These security
loopholes can be exploited by potential attackers to launch attack on WMNs. The
absence of a central point of administration makes securing WMNs even more
challenging. The broadcast nature of transmission and the dependency on the
intermediate nodes for multi-hop communications lead to several security
vulnerabilities in WMNs. The attacks can be external as well as internal in
nature. External attacks are launched by intruders who are not authorized users
of the network. For example, an intruding node may eavesdrop on the packets and
replay those packets at a later point of time to gain access to the network
resources. On the other hand, the internal attacks are launched by the nodes
that are part of the WMN. On example of such attack is an intermediate node
dropping packets which it was supposed to forward. This chapter presents a
comprehensive discussion on the current authentication and privacy protection
schemes for WMN. In addition, it proposes a novel security protocol for node
authentication and message confidentiality and an anonymization scheme for
privacy protection of users in WMNs.Comment: 32 pages, 10 figures. The work is an extended version of the author's
previous works submitted in CoRR: arXiv:1107.5538v1 and arXiv:1102.1226v
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