72,571 research outputs found
Information-Theoretic Security for the Masses
We combine interactive zero-knowledge protocols and weak physical layer
randomness properties to construct a protocol which allows bootstrapping an
IT-secure and PF-secure channel from a memorizable shared secret. The protocol
also tolerates failures of its components, still preserving most of its
security properties, which makes it accessible to regular users.Comment: 4 page
Techniques for Enhanced Physical-Layer Security
Information-theoretic security--widely accepted as the strictest notion of
security--relies on channel coding techniques that exploit the inherent
randomness of propagation channels to strengthen the security of communications
systems. Within this paradigm, we explore strategies to improve secure
connectivity in a wireless network. We first consider the intrinsically secure
communications graph (iS-graph), a convenient representation of the links that
can be established with information-theoretic security on a large-scale
network. We then propose and characterize two techniques--sectorized
transmission and eavesdropper neutralization--which are shown to dramatically
enhance the connectivity of the iS-graph.Comment: Pre-print, IEEE Global Telecommunications Conference (GLOBECOM'10),
Miami, FL, Dec. 201
Information-theoretic Physical Layer Security for Satellite Channels
Shannon introduced the classic model of a cryptosystem in 1949, where Eve has
access to an identical copy of the cyphertext that Alice sends to Bob. Shannon
defined perfect secrecy to be the case when the mutual information between the
plaintext and the cyphertext is zero. Perfect secrecy is motivated by
error-free transmission and requires that Bob and Alice share a secret key.
Wyner in 1975 and later I.~Csisz\'ar and J.~K\"orner in 1978 modified the
Shannon model assuming that the channels are noisy and proved that secrecy can
be achieved without sharing a secret key. This model is called wiretap channel
model and secrecy capacity is known when Eve's channel is noisier than Bob's
channel.
In this paper we review the concept of wiretap coding from the satellite
channel viewpoint. We also review subsequently introduced stronger secrecy
levels which can be numerically quantified and are keyless unconditionally
secure under certain assumptions. We introduce the general construction of
wiretap coding and analyse its applicability for a typical satellite channel.
From our analysis we discuss the potential of keyless information theoretic
physical layer security for satellite channels based on wiretap coding. We also
identify system design implications for enabling simultaneous operation with
additional information theoretic security protocols
An information-theoretic security proof for QKD protocols
We present a new technique for proving the security of quantum key
distribution (QKD) protocols. It is based on direct information-theoretic
arguments and thus also applies if no equivalent entanglement purification
scheme can be found. Using this technique, we investigate a general class of
QKD protocols with one-way classical post-processing. We show that, in order to
analyze the full security of these protocols, it suffices to consider
collective attacks. Indeed, we give new lower and upper bounds on the
secret-key rate which only involve entropies of two-qubit density operators and
which are thus easy to compute. As an illustration of our results, we analyze
the BB84, the six-state, and the B92 protocol with one-way error correction and
privacy amplification. Surprisingly, the performance of these protocols is
increased if one of the parties adds noise to the measurement data before the
error correction. In particular, this additional noise makes the protocols more
robust against noise in the quantum channel.Comment: 18 pages, 3 figure
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