8,514 research outputs found
RFID Key Establishment Against Active Adversaries
We present a method to strengthen a very low cost solution for key agreement
with a RFID device.
Starting from a work which exploits the inherent noise on the communication
link to establish a key by public discussion, we show how to protect this
agreement against active adversaries. For that purpose, we unravel integrity
-codes suggested by Cagalj et al.
No preliminary key distribution is required.Comment: This work was presented at the First IEEE Workshop on Information
Forensics and Security (WIFS'09) (update including minor remarks and
references to match the presented version
The Minimum Distance Problem for Two-Way Entanglement Purification
Entanglement purification takes a number of noisy EPR pairs and processes
them to produce a smaller number of more reliable pairs. If this is done with
only a forward classical side channel, the procedure is equivalent to using a
quantum error-correcting code (QECC). We instead investigate entanglement
purification protocols with two-way classical side channels (2-EPPs) for finite
block sizes. In particular, we consider the analog of the minimum distance
problem for QECCs, and show that 2-EPPs can exceed the quantum Hamming bound
and the quantum Singleton bound. We also show that 2-EPPs can achieve the rate
k/n = 1 - (t/n) \log_2 3 - h(t/n) - O(1/n) (asymptotically reaching the quantum
Hamming bound), where the EPP produces at least k good pairs out of n total
pairs with up to t arbitrary errors, and h(x) = -x \log_2 x - (1-x) \log_2
(1-x) is the usual binary entropy. In contrast, the best known lower bound on
the rate of QECCs is the quantum Gilbert-Varshamov bound k/n \geq 1 - (2t/n)
\log_2 3 - h(2t/n). Indeed, in some regimes, the known upper bound on the
asymptotic rate of good QECCs is strictly below our lower bound on the
achievable rate of 2-EPPs.Comment: 10 pages, LaTeX. v2: New title, minor corrections and clarifications,
some new references. v3: One more small correction. v4: More small
clarifications, final version to appear in IEEE Trans. Info. Theor
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
An Adaptive Entanglement Distillation Scheme Using Quantum Low Density Parity Check Codes
Quantum low density parity check (QLDPC) codes are useful primitives for
quantum information processing because they can be encoded and decoded
efficiently. Besides, the error correcting capability of a few QLDPC codes
exceeds the quantum Gilbert-Varshamov bound. Here, we report a numerical
performance analysis of an adaptive entanglement distillation scheme using
QLDPC codes. In particular, we find that the expected yield of our adaptive
distillation scheme to combat depolarization errors exceed that of Leung and
Shor whenever the error probability is less than about 0.07 or greater than
about 0.28. This finding illustrates the effectiveness of using QLDPC codes in
entanglement distillation.Comment: 12 pages, 6 figure
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