423 research outputs found
Secure Communication over Parallel Relay Channel
We investigate the problem of secure communication over parallel relay
channel in the presence of a passive eavesdropper. We consider a four terminal
relay-eavesdropper channel which consists of multiple relay-eavesdropper
channels as subchannels. For the discrete memoryless model, we establish outer
and inner bounds on the rate-equivocation region. The inner bound allows mode
selection at the relay. For each subchannel, secure transmission is obtained
through one of two coding schemes at the relay: decoding-and-forwarding the
source message or confusing the eavesdropper through noise injection. For the
Gaussian memoryless channel, we establish lower and upper bounds on the perfect
secrecy rate. Furthermore, we study a special case in which the relay does not
hear the source and show that under certain conditions the lower and upper
bounds coincide. The results established for the parallel Gaussian
relay-eavesdropper channel are then applied to study the fading
relay-eavesdropper channel. Analytical results are illustrated through some
numerical examples.Comment: To Appear in IEEE Transactions on Information Forensics and Securit
Lists that are smaller than their parts: A coding approach to tunable secrecy
We present a new information-theoretic definition and associated results,
based on list decoding in a source coding setting. We begin by presenting
list-source codes, which naturally map a key length (entropy) to list size. We
then show that such codes can be analyzed in the context of a novel
information-theoretic metric, \epsilon-symbol secrecy, that encompasses both
the one-time pad and traditional rate-based asymptotic metrics, but, like most
cryptographic constructs, can be applied in non-asymptotic settings. We derive
fundamental bounds for \epsilon-symbol secrecy and demonstrate how these bounds
can be achieved with MDS codes when the source is uniformly distributed. We
discuss applications and implementation issues of our codes.Comment: Allerton 2012, 8 page
- …