80,755 research outputs found
Hiding Symbols and Functions: New Metrics and Constructions for Information-Theoretic Security
We present information-theoretic definitions and results for analyzing
symmetric-key encryption schemes beyond the perfect secrecy regime, i.e. when
perfect secrecy is not attained. We adopt two lines of analysis, one based on
lossless source coding, and another akin to rate-distortion theory. We start by
presenting a new information-theoretic metric for security, called symbol
secrecy, and derive associated fundamental bounds. We then introduce
list-source codes (LSCs), which are a general framework for mapping a key
length (entropy) to a list size that an eavesdropper has to resolve in order to
recover a secret message. We provide explicit constructions of LSCs, and
demonstrate that, when the source is uniformly distributed, the highest level
of symbol secrecy for a fixed key length can be achieved through a construction
based on minimum-distance separable (MDS) codes. Using an analysis related to
rate-distortion theory, we then show how symbol secrecy can be used to
determine the probability that an eavesdropper correctly reconstructs functions
of the original plaintext. We illustrate how these bounds can be applied to
characterize security properties of symmetric-key encryption schemes, and, in
particular, extend security claims based on symbol secrecy to a functional
setting.Comment: Submitted to IEEE Transactions on Information Theor
Universal Secure Multiplex Network Coding with Dependent and Non-Uniform Messages
We consider the random linear precoder at the source node as a secure network
coding. We prove that it is strongly secure in the sense of Harada and Yamamoto
and universal secure in the sense of Silva and Kschischang, while allowing
arbitrary small but nonzero mutual information to the eavesdropper. Our
security proof allows statistically dependent and non-uniform multiple secret
messages, while all previous constructions of weakly or strongly secure network
coding assumed independent and uniform messages, which are difficult to be
ensured in practice.Comment: 10 pages, 1 figure, IEEEtrans.cls. Online published in IEEE Trans.
Inform. Theor
Achievable Secrecy Rates of an Energy Harvesting Device
The secrecy rate represents the amount of information per unit time that can
be securely sent on a communication link. In this work, we investigate the
achievable secrecy rates in an energy harvesting communication system composed
of a transmitter, a receiver and a malicious eavesdropper. In particular,
because of the energy constraints and the channel conditions, it is important
to understand when a device should transmit and to optimize how much power
should be used in order to improve security. Both full knowledge and partial
knowledge of the channel are considered under a Nakagami fading scenario. We
show that high secrecy rates can be obtained only with power and coding rate
adaptation. Moreover, we highlight the importance of optimally dividing the
transmission power in the frequency domain, and note that the optimal scheme
provides high gains in secrecy rate over the uniform power splitting case.
Analytically, we explain how to find the optimal policy and prove some of its
properties. In our numerical evaluation, we discuss how the maximum achievable
secrecy rate changes according to the various system parameters. Furthermore,
we discuss the effects of a finite battery on the system performance and note
that, in order to achieve high secrecy rates, it is not necessary to use very
large batteries.Comment: Accepted for publication in IEEE Journal on Selected Areas in
Communications (Mar. 2016
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