3,983 research outputs found
The Wiretap Channel with Feedback: Encryption over the Channel
In this work, the critical role of noisy feedback in enhancing the secrecy
capacity of the wiretap channel is established. Unlike previous works, where a
noiseless public discussion channel is used for feedback, the feed-forward and
feedback signals share the same noisy channel in the present model. Quite
interestingly, this noisy feedback model is shown to be more advantageous in
the current setting. More specifically, the discrete memoryless modulo-additive
channel with a full-duplex destination node is considered first, and it is
shown that the judicious use of feedback increases the perfect secrecy capacity
to the capacity of the source-destination channel in the absence of the
wiretapper. In the achievability scheme, the feedback signal corresponds to a
private key, known only to the destination. In the half-duplex scheme, a novel
feedback technique that always achieves a positive perfect secrecy rate (even
when the source-wiretapper channel is less noisy than the source-destination
channel) is proposed. These results hinge on the modulo-additive property of
the channel, which is exploited by the destination to perform encryption over
the channel without revealing its key to the source. Finally, this scheme is
extended to the continuous real valued modulo- channel where it is
shown that the perfect secrecy capacity with feedback is also equal to the
capacity in the absence of the wiretapper.Comment: Submitted to IEEE Transactions on Information Theor
Gossip Codes for Fingerprinting: Construction, Erasure Analysis and Pirate Tracing
This work presents two new construction techniques for q-ary Gossip codes
from tdesigns and Traceability schemes. These Gossip codes achieve the shortest
code length specified in terms of code parameters and can withstand erasures in
digital fingerprinting applications. This work presents the construction of
embedded Gossip codes for extending an existing Gossip code into a bigger code.
It discusses the construction of concatenated codes and realisation of erasure
model through concatenated codes.Comment: 28 page
Secret Communication over Broadcast Erasure Channels with State-feedback
We consider a 1-to- communication scenario, where a source transmits
private messages to receivers through a broadcast erasure channel, and the
receivers feed back strictly causally and publicly their channel states after
each transmission. We explore the achievable rate region when we require that
the message to each receiver remains secret - in the information theoretical
sense - from all the other receivers. We characterize the capacity of secure
communication in all the cases where the capacity of the 1-to- communication
scenario without the requirement of security is known. As a special case, we
characterize the secret-message capacity of a single receiver point-to-point
erasure channel with public state-feedback in the presence of a passive
eavesdropper.
We find that in all cases where we have an exact characterization, we can
achieve the capacity by using linear complexity two-phase schemes: in the first
phase we create appropriate secret keys, and in the second phase we use them to
encrypt each message. We find that the amount of key we need is smaller than
the size of the message, and equal to the amount of encrypted message the
potential eavesdroppers jointly collect. Moreover, we prove that a dishonest
receiver that provides deceptive feedback cannot diminish the rate experienced
by the honest receivers.
We also develop a converse proof which reflects the two-phase structure of
our achievability scheme. As a side result, our technique leads to a new outer
bound proof for the non-secure communication problem
Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey
This paper provides a comprehensive review of the domain of physical layer
security in multiuser wireless networks. The essential premise of
physical-layer security is to enable the exchange of confidential messages over
a wireless medium in the presence of unauthorized eavesdroppers without relying
on higher-layer encryption. This can be achieved primarily in two ways: without
the need for a secret key by intelligently designing transmit coding
strategies, or by exploiting the wireless communication medium to develop
secret keys over public channels. The survey begins with an overview of the
foundations dating back to the pioneering work of Shannon and Wyner on
information-theoretic security. We then describe the evolution of secure
transmission strategies from point-to-point channels to multiple-antenna
systems, followed by generalizations to multiuser broadcast, multiple-access,
interference, and relay networks. Secret-key generation and establishment
protocols based on physical layer mechanisms are subsequently covered.
Approaches for secrecy based on channel coding design are then examined, along
with a description of inter-disciplinary approaches based on game theory and
stochastic geometry. The associated problem of physical-layer message
authentication is also introduced briefly. The survey concludes with
observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with
arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials,
201
Quantum data hiding in the presence of noise
When classical or quantum information is broadcast to separate receivers,
there exist codes that encrypt the encoded data such that the receivers cannot
recover it when performing local operations and classical communication, but
they can decode reliably if they bring their systems together and perform a
collective measurement. This phenomenon is known as quantum data hiding and
hitherto has been studied under the assumption that noise does not affect the
encoded systems. With the aim of applying the quantum data hiding effect in
practical scenarios, here we define the data-hiding capacity for hiding
classical information using a quantum channel. Using this notion, we establish
a regularized upper bound on the data hiding capacity of any quantum broadcast
channel, and we prove that coherent-state encodings have a strong limitation on
their data hiding rates. We then prove a lower bound on the data hiding
capacity of channels that map the maximally mixed state to the maximally mixed
state (we call these channels "mictodiactic"---they can be seen as a
generalization of unital channels when the input and output spaces are not
necessarily isomorphic) and argue how to extend this bound to generic channels
and to more than two receivers.Comment: 12 pages, accepted for publication in IEEE Transactions on
Information Theor
Deep Random based Key Exchange protocol resisting unlimited MITM
We present a protocol enabling two legitimate partners sharing an initial
secret to mutually authenticate and to exchange an encryption session key. The
opponent is an active Man In The Middle (MITM) with unlimited computation and
storage capacities. The resistance to unlimited MITM is obtained through the
combined use of Deep Random secrecy, formerly introduced and proved as
unconditionally secure against passive opponent for key exchange, and universal
hashing techniques. We prove the resistance to MITM interception attacks, and
show that (i) upon successful completion, the protocol leaks no residual
information about the current value of the shared secret to the opponent, and
(ii) that any unsuccessful completion is detectable by the legitimate partners.
We also discuss implementation techniques.Comment: 14 pages. V2: Updated reminder in the formalism of Deep Random
assumption. arXiv admin note: text overlap with arXiv:1611.01683,
arXiv:1507.0825
- …