10,721 research outputs found
Quantum Cryptography Beyond Quantum Key Distribution
Quantum cryptography is the art and science of exploiting quantum mechanical
effects in order to perform cryptographic tasks. While the most well-known
example of this discipline is quantum key distribution (QKD), there exist many
other applications such as quantum money, randomness generation, secure two-
and multi-party computation and delegated quantum computation. Quantum
cryptography also studies the limitations and challenges resulting from quantum
adversaries---including the impossibility of quantum bit commitment, the
difficulty of quantum rewinding and the definition of quantum security models
for classical primitives. In this review article, aimed primarily at
cryptographers unfamiliar with the quantum world, we survey the area of
theoretical quantum cryptography, with an emphasis on the constructions and
limitations beyond the realm of QKD.Comment: 45 pages, over 245 reference
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
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: 1â47
Security bound of two-bases quantum key-distribution protocols using qudits
We investigate the security bounds of quantum cryptographic protocols using
-level systems. In particular, we focus on schemes that use two mutually
unbiased bases, thus extending the BB84 quantum key distribution scheme to
higher dimensions. Under the assumption of general coherent attacks, we derive
an analytic expression for the ultimate upper security bound of such quantum
cryptography schemes. This bound is well below the predictions of optimal
cloning machines. The possibility of extraction of a secret key beyond
entanglement distillation is discussed. In the case of qutrits we argue that
any eavesdropping strategy is equivalent to a symmetric one. For higher
dimensions such an equivalence is generally no longer valid.Comment: 12 pages, 2 figures, to appear in Phys. Rev.
Quantum oblivious transfer: a short review
Quantum cryptography is the field of cryptography that explores the quantum
properties of matter. Its aim is to develop primitives beyond the reach of
classical cryptography or to improve on existing classical implementations.
Although much of the work in this field is dedicated to quantum key
distribution (QKD), some important steps were made towards the study and
development of quantum oblivious transfer (QOT). It is possible to draw a
comparison between the application structure of both QKD and QOT primitives.
Just as QKD protocols allow quantum-safe communication, QOT protocols allow
quantum-safe computation. However, the conditions under which QOT is actually
quantum-safe have been subject to a great amount of scrutiny and study. In this
review article, we survey the work developed around the concept of oblivious
transfer in the area of theoretical quantum cryptography, with an emphasis on
some proposed protocols and their security requirements. We review the
impossibility results that daunt this primitive and discuss several quantum
security models under which it is possible to prove QOT security.Comment: 40 pages, 14 figure
Secure Key from Quantum Discord
The study of quantum information processing seeks to characterize the
resources that enable quantum information processing to perform tasks that are
unfeasible or inefficient for classical information processing. Quantum
cryptography is one such task, and researchers have identified entanglement as
a sufficient resource for secure key generation. However, quantum discord,
another type of quantum correlation beyond entanglement, has been found to be
necessary for guaranteeing secure communication due to its direct relation to
information leakage. Despite this, it is a long-standing problem how to make
use of discord to analyze security in a specific quantum cryptography protocol.
Here, based on our proposed quantum discord witness recently, we successfully
address this issue by considering a BB84-like quantum key distribution protocol
and its equivalent entanglement-based version. Our method is robust against
imperfections in qubit sources and qubit measurements as well as basis
misalignment due to quantum channels, which results in a better key rate than
standard BB84 protocol. Those advantages are experimentally demonstrated via
photonic phase encoding systems, which shows the practicality of our results
Security of Quantum Key Distribution Protocols
Quantum key distribution (QKD), another name for quantum cryptography, is the most advanced subfield of quantum information and communication technology (QICT). The first QKD protocol was proposed in 1984, and since then, more protocols have been proposed. It uses quantum mechanics to enable secure exchange of cryptographic keys. In order to have high confidence in the security of the QKD protocols, such protocols must be proven to be secure against any arbitrary attacks. In this chapter, we discuss and demonstrate security proofs for QKD protocols. Security analysis of QKD protocols can be categorised into two techniques, namely infinite-key and finite-key analyses. Finite-key analysis offers more realistic results than the infinite-key one, while infinite-key analysis provides more simplicity. We briefly provide the background of QKD and also define the basic notion of security in QKD protocols. The cryptographic key is shared between Alice and Bob. Since the key is random and unknown to an eavesdropper, Eve, she is unable to learn anything about the message simply by intercepting the ciphertext. This phenomenon is beyond the ability of classical information processing. We then study some tools that are used in the derivation of security proofs for the infinite- and finite-length key limits
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