423 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.
Random Oracles in a Quantum World
The interest in post-quantum cryptography - classical systems that remain
secure in the presence of a quantum adversary - has generated elegant proposals
for new cryptosystems. Some of these systems are set in the random oracle model
and are proven secure relative to adversaries that have classical access to the
random oracle. We argue that to prove post-quantum security one needs to prove
security in the quantum-accessible random oracle model where the adversary can
query the random oracle with quantum states.
We begin by separating the classical and quantum-accessible random oracle
models by presenting a scheme that is secure when the adversary is given
classical access to the random oracle, but is insecure when the adversary can
make quantum oracle queries. We then set out to develop generic conditions
under which a classical random oracle proof implies security in the
quantum-accessible random oracle model. We introduce the concept of a
history-free reduction which is a category of classical random oracle
reductions that basically determine oracle answers independently of the history
of previous queries, and we prove that such reductions imply security in the
quantum model. We then show that certain post-quantum proposals, including ones
based on lattices, can be proven secure using history-free reductions and are
therefore post-quantum secure. We conclude with a rich set of open problems in
this area.Comment: 38 pages, v2: many substantial changes and extensions, merged with a
related paper by Boneh and Zhandr
Review on DNA Cryptography
Cryptography is the science that secures data and communication over the
network by applying mathematics and logic to design strong encryption methods.
In the modern era of e-business and e-commerce the protection of
confidentiality, integrity and availability (CIA triad) of stored information
as well as of transmitted data is very crucial. DNA molecules, having the
capacity to store, process and transmit information, inspires the idea of DNA
cryptography. This combination of the chemical characteristics of biological
DNA sequences and classical cryptography ensures the non-vulnerable
transmission of data. In this paper we have reviewed the present state of art
of DNA cryptography.Comment: 31 pages, 12 figures, 6 table
URDP: General Framework for Direct CCA2 Security from any Lattice-Based PKE Scheme
Design efficient lattice-based cryptosystem secure against adaptive chosen
ciphertext attack (IND-CCA2) is a challenge problem. To the date, full
CCA2-security of all proposed lattice-based PKE schemes achieved by using a
generic transformations such as either strongly unforgeable one-time signature
schemes (SU-OT-SS), or a message authentication code (MAC) and weak form of
commitment. The drawback of these schemes is that encryption requires "separate
encryption". Therefore, the resulting encryption scheme is not sufficiently
efficient to be used in practice and it is inappropriate for many applications
such as small ubiquitous computing devices with limited resources such as smart
cards, active RFID tags, wireless sensor networks and other embedded devices.
In this work, for the first time, we introduce an efficient universal random
data padding (URDP) scheme, and show how it can be used to construct a "direct"
CCA2-secure encryption scheme from "any" worst-case hardness problems in
(ideal) lattice in the standard model, resolving a problem that has remained
open till date. This novel approach is a "black-box" construction and leads to
the elimination of separate encryption, as it avoids using general
transformation from CPA-secure scheme to a CCA2-secure one. IND-CCA2 security
of this scheme can be tightly reduced in the standard model to the assumption
that the underlying primitive is an one-way trapdoor function.Comment: arXiv admin note: text overlap with arXiv:1302.0347, arXiv:1211.6984;
and with arXiv:1205.5224 by other author
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Post-quantum blockchain for internet of things domain
This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonIn the evolving realm of quantum computing, emerging advancements reveal substantial challenges and threats to existing cryptographic infrastructures, particularly impacting blockchain technologies. These are pivotal for securing the Internet of Things (IoT) ecosystems. The traditional blockchain structures, integral to myriad IoT applications, are susceptible to potential quantum computations, emphasizing an urgent need for innovations in post-quantum blockchain solutions to reinforce security in the expansive domain of IoT.
This PhD thesis delves into the crucial exploration and meticulous examination of the development and implementation of post-quantum blockchain within the IoT landscape, focusing on the incorporation of advanced post-quantum cryptographic algorithms in Hyperledger Fabric, a forefront blockchain platform renowned for its versatility and robustness. The primary aim is to discern viable post-quantum cryptographic solutions capable of fortifying blockchain systems against impending quantum threats enhancing security and reliability in IoT applications.
The research comprehensively evaluates various post-quantum public-key generation and digital signature algorithms, performing detailed analyses of their computational time and memory usage to identify optimal candidates. Furthermore, the thesis proposes an innovative lattice-based digital signature scheme Fast-Fourier Lattice-based Compact Signature over NTRU (Falcon), which leverages the Monte Carlo Markov Chain (MCMC) algorithm as a trapdoor sampler to augment its security attributes.
The research introduces a post-quantum version of the Hyperledger Fabric blockchain that integrates post-quantum signatures. The system utilizes the Open Quantum Safe (OQS) library, rigorously tested against NIST round 3 candidates for optimal performance. The study highlights the capability to manage IoT data securely on the post-quantum Hyperledger Fabric blockchain through the Message Queue Telemetry Transport (MQTT) protocol. Such a configuration ensures safe data transfer from IoT sensors directly to the blockchain nodes, securing the processing and recording of sensor data within the node ledger. The research addresses the multifaceted challenges of quantum computing advancements and significantly contributes to establishing secure, efficient, and resilient post-quantum blockchain infrastructures tailored explicitly for the IoT domain. These findings are instrumental in elevating the security paradigms of IoT systems against quantum vulnerabilities and catalysing innovations in post-quantum cryptography and blockchain technologies.
Furthermore, this thesis introduces strategies for the optimization of performance and scalability of post-quantum blockchain solutions and explores alternative, energy-efficient consensus mechanisms such as the Raft and Stellar Consensus Protocol (SCP), providing sustainable alternatives to the conventional Proof-of-Work (PoW) approach.
A critical insight emphasized throughout this thesis is the imperative of synergistic collaboration among academia, industry, and regulatory bodies. This collaboration is pivotal to expedite the adoption and standardization of post-quantum blockchain solutions, fostering the development of interoperable and standardized technologies enriched with robust security and privacy frameworks for end users.
In conclusion, this thesis furnishes profound insights and substantial contributions to implementing post-quantum blockchain in the IoT domain. It delineates original contributions to the knowledge and practices in the field, offering practical solutions and advancing the state-of-the-art in post-quantum cryptography and blockchain research, thereby paving the way for a secure and resilient future for interconnected IoT systems
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