15,788 research outputs found
Truly Efficient 2-Round Perfectly Secure Message Transmission Scheme
In the model of perfectly secure message transmission schemes (PSMTs), there are channels between a sender and a receiver. An infinitely powerful adversary \A may corrupt (observe and forge)the messages sent through out of channels. The sender wishes to send a secret to the receiver perfectly privately and perfectly reliably without sharing any key with the receiver.
In this paper, we show the first -round PSMT for such that not only the transmission rate is but also the computational costs of the sender and the receiver are both polynomial in . This means that we solve the open problem raised by
Agarwal, Cramer and de Haan at CRYPTO 2006
Perfectly secure message transmission in two rounds
In the model that has become known as "Perfectly Secure Message Transmission"(PSMT), a sender Alice is connected to a receiver Bob through n parallel two-way channels. A computationally unbounded adversary Eve controls t of these channels, meaning she can acquire and alter any data that is transmitted over these channels. The sender Alice wishes to communicate a secret message to Bob privately and reliably, i.e. in such a way that Eve will not get any information about the message while Bob will be able to recover it completely.
In this paper, we focus on protocols that work in two transmission rounds for n= 2t+1. We break from previous work by following a conceptually simpler blueprint for achieving a PSMT protocol. We reduce the previously best-known communication complexity, i.e. the number of transmitted bits necessary to communicate a 1-bit secret, from O(n^3 log n) to O(n^2 log n). Our protocol also answers a question raised by Kurosawa and Suzuki and hitherto left open: their protocol reaches optimal transmission rate for a secret of size O(n^2 log n) bits, and the authors raised the problem of lowering this threshold. The present solution does this for a secret of O(n log n) bits
On one-round reliable message transmission
In this paper, we consider one-round protocols for reliable message transmission (RMT) when out of available channels are controlled by an adversary. We show impossibility of constructing such a protocol that achieves a transmission rate of less than for constant-size messages and arbitrary reliability parameter. In addition, we show how to improve two existing protocols for RMT to allow for either larger messages or reduced field sizes
Private Randomness Agreement and its Application in Quantum Key Distribution Networks
We define a variation on the well-known problem of private message
transmission. This new problem called private randomness agreement (PRA) gives
two participants access to a public, authenticated channel alongside the main
channels, and the 'message' is not fixed a priori.
Instead, the participants aim to agree on a random string completely unknown
to a computationally unbounded adversary.
We define privacy and reliability, and show that PRA cannot be solved in a
single round. We then show that it can be solved in three rounds, albeit with
exponential cost, and give an efficient four-round protocol based on polynomial
evaluation.Comment: 6 page
Quantum Cryptography
Quantum cryptography could well be the first application of quantum mechanics
at the individual quanta level. The very fast progress in both theory and
experiments over the recent years are reviewed, with emphasis on open questions
and technological issues.Comment: 55 pages, 32 figures; to appear in Reviews of Modern Physic
Revisiting Deniability in Quantum Key Exchange via Covert Communication and Entanglement Distillation
We revisit the notion of deniability in quantum key exchange (QKE), a topic
that remains largely unexplored. In the only work on this subject by Donald
Beaver, it is argued that QKE is not necessarily deniable due to an
eavesdropping attack that limits key equivocation. We provide more insight into
the nature of this attack and how it extends to other constructions such as QKE
obtained from uncloneable encryption. We then adopt the framework for quantum
authenticated key exchange, developed by Mosca et al., and extend it to
introduce the notion of coercer-deniable QKE, formalized in terms of the
indistinguishability of real and fake coercer views. Next, we apply results
from a recent work by Arrazola and Scarani on covert quantum communication to
establish a connection between covert QKE and deniability. We propose DC-QKE, a
simple deniable covert QKE protocol, and prove its deniability via a reduction
to the security of covert QKE. Finally, we consider how entanglement
distillation can be used to enable information-theoretically deniable protocols
for QKE and tasks beyond key exchange.Comment: 16 pages, published in the proceedings of NordSec 201
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