284 research outputs found
Converses for Secret Key Agreement and Secure Computing
We consider information theoretic secret key agreement and secure function
computation by multiple parties observing correlated data, with access to an
interactive public communication channel. Our main result is an upper bound on
the secret key length, which is derived using a reduction of binary hypothesis
testing to multiparty secret key agreement. Building on this basic result, we
derive new converses for multiparty secret key agreement. Furthermore, we
derive converse results for the oblivious transfer problem and the bit
commitment problem by relating them to secret key agreement. Finally, we derive
a necessary condition for the feasibility of secure computation by trusted
parties that seek to compute a function of their collective data, using an
interactive public communication that by itself does not give away the value of
the function. In many cases, we strengthen and improve upon previously known
converse bounds. Our results are single-shot and use only the given joint
distribution of the correlated observations. For the case when the correlated
observations consist of independent and identically distributed (in time)
sequences, we derive strong versions of previously known converses
"Pretty strong" converse for the private capacity of degraded quantum wiretap channels
In the vein of the recent "pretty strong" converse for the quantum and
private capacity of degradable quantum channels [Morgan/Winter, IEEE Trans.
Inf. Theory 60(1):317-333, 2014], we use the same techniques, in particular the
calculus of min-entropies, to show a pretty strong converse for the private
capacity of degraded classical-quantum-quantum (cqq-)wiretap channels, which
generalize Wyner's model of the degraded classical wiretap channel.
While the result is not completely tight, leaving some gap between the region
of error and privacy parameters for which the converse bound holds, and a
larger no-go region, it represents a further step towards an understanding of
strong converses of wiretap channels [cf. Hayashi/Tyagi/Watanabe,
arXiv:1410.0443 for the classical case].Comment: 5 pages, 1 figure, IEEEtran.cls. V2 final (conference) version,
accepted for ISIT 2016 (Barcelona, 10-15 July 2016
Strong Converse for a Degraded Wiretap Channel via Active Hypothesis Testing
We establish an upper bound on the rate of codes for a wiretap channel with
public feedback for a fixed probability of error and secrecy parameter. As a
corollary, we obtain a strong converse for the capacity of a degraded wiretap
channel with public feedback. Our converse proof is based on a reduction of
active hypothesis testing for discriminating between two channels to coding for
wiretap channel with feedback.Comment: This paper was presented at Allerton 201
The Oblivious Transfer Capacity of the Wiretapped Binary Erasure Channel
We consider oblivious transfer between Alice and Bob in the presence of an
eavesdropper Eve when there is a broadcast channel from Alice to Bob and Eve.
In addition to the secrecy constraints of Alice and Bob, Eve should not learn
the private data of Alice and Bob. When the broadcast channel consists of two
independent binary erasure channels, we derive the oblivious transfer capacity
for both 2-privacy (where the eavesdropper may collude with either party) and
1-privacy (where there are no collusions).Comment: This is an extended version of the paper "The Oblivious Transfer
Capacity of the Wiretapped Binary Erasure Channel" to be presented at ISIT
201
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