4,338 research outputs found
Classical Cryptographic Protocols in a Quantum World
Cryptographic protocols, such as protocols for secure function evaluation
(SFE), have played a crucial role in the development of modern cryptography.
The extensive theory of these protocols, however, deals almost exclusively with
classical attackers. If we accept that quantum information processing is the
most realistic model of physically feasible computation, then we must ask: what
classical protocols remain secure against quantum attackers?
Our main contribution is showing the existence of classical two-party
protocols for the secure evaluation of any polynomial-time function under
reasonable computational assumptions (for example, it suffices that the
learning with errors problem be hard for quantum polynomial time). Our result
shows that the basic two-party feasibility picture from classical cryptography
remains unchanged in a quantum world.Comment: Full version of an old paper in Crypto'11. Invited to IJQI. This is
authors' copy with different formattin
Classical cryptographic protocols in a quantum world
Cryptographic protocols, such as protocols for secure function evaluation (SFE), have played a crucial role in the development of modern cryptography. The extensive theory of these protocols, however, deals almost exclusively with classical attackers. If we accept that quantum information processing is the most realistic model of physically feasible computation, then we must ask: what classical protocols remain secure against quantum attackers? Our main contribution is showing the existence of classical two-party protocols for the secure evaluation of any polynomial-time function under reasonable computational assumptions (for example, it suffices that the learning with errors problem be hard for quantum polynomial time). Our result shows that the basic two-party feasibility picture from classical cryptography remains unchanged in a quantum world
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
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.
Unconditionally Secure Bit Commitment
We describe a new classical bit commitment protocol based on cryptographic
constraints imposed by special relativity. The protocol is unconditionally
secure against classical or quantum attacks. It evades the no-go results of
Mayers, Lo and Chau by requiring from Alice a sequence of communications,
including a post-revelation verification, each of which is guaranteed to be
independent of its predecessor.Comment: Typos corrected. Reference details added. To appear in Phys. Rev.
Let
Using quantum key distribution for cryptographic purposes: a survey
The appealing feature of quantum key distribution (QKD), from a cryptographic
viewpoint, is the ability to prove the information-theoretic security (ITS) of
the established keys. As a key establishment primitive, QKD however does not
provide a standalone security service in its own: the secret keys established
by QKD are in general then used by a subsequent cryptographic applications for
which the requirements, the context of use and the security properties can
vary. It is therefore important, in the perspective of integrating QKD in
security infrastructures, to analyze how QKD can be combined with other
cryptographic primitives. The purpose of this survey article, which is mostly
centered on European research results, is to contribute to such an analysis. We
first review and compare the properties of the existing key establishment
techniques, QKD being one of them. We then study more specifically two generic
scenarios related to the practical use of QKD in cryptographic infrastructures:
1) using QKD as a key renewal technique for a symmetric cipher over a
point-to-point link; 2) using QKD in a network containing many users with the
objective of offering any-to-any key establishment service. We discuss the
constraints as well as the potential interest of using QKD in these contexts.
We finally give an overview of challenges relative to the development of QKD
technology that also constitute potential avenues for cryptographic research.Comment: Revised version of the SECOQC White Paper. Published in the special
issue on QKD of TCS, Theoretical Computer Science (2014), pp. 62-8
Feasibility of the interlock protocol against man-in-the-middle attacks on quantum cryptography
If an eavesdropper succeeds in compromising the quantum as well as the
classical channels and mimics the receiver "Bob" for the sender "Alice" and
vice versa, one defence strategy is the successive, temporally interlocked
partial transmission of the entire encrypted message
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