10 research outputs found
Secure Cooperative Regenerating Codes for Distributed Storage Systems
Regenerating codes enable trading off repair bandwidth for storage in
distributed storage systems (DSS). Due to their distributed nature, these
systems are intrinsically susceptible to attacks, and they may also be subject
to multiple simultaneous node failures. Cooperative regenerating codes allow
bandwidth efficient repair of multiple simultaneous node failures. This paper
analyzes storage systems that employ cooperative regenerating codes that are
robust to (passive) eavesdroppers. The analysis is divided into two parts,
studying both minimum bandwidth and minimum storage cooperative regenerating
scenarios. First, the secrecy capacity for minimum bandwidth cooperative
regenerating codes is characterized. Second, for minimum storage cooperative
regenerating codes, a secure file size upper bound and achievability results
are provided. These results establish the secrecy capacity for the minimum
storage scenario for certain special cases. In all scenarios, the achievability
results correspond to exact repair, and secure file size upper bounds are
obtained using min-cut analyses over a suitable secrecy graph representation of
DSS. The main achievability argument is based on an appropriate pre-coding of
the data to eliminate the information leakage to the eavesdropper
Generic Secure Repair for Distributed Storage
This paper studies the problem of repairing secret sharing schemes, i.e.,
schemes that encode a message into shares, assigned to nodes, so that
any nodes can decode the message but any colluding nodes cannot infer
any information about the message. In the event of node failures so that shares
held by the failed nodes are lost, the system needs to be repaired by
reconstructing and reassigning the lost shares to the failed (or replacement)
nodes. This can be achieved trivially by a trustworthy third-party that
receives the shares of the available nodes, recompute and reassign the lost
shares. The interesting question, studied in the paper, is how to repair
without a trustworthy third-party. The main issue that arises is repair
security: how to maintain the requirement that any colluding nodes,
including the failed nodes, cannot learn any information about the message,
during and after the repair process? We solve this secure repair problem from
the perspective of secure multi-party computation. Specifically, we design
generic repair schemes that can securely repair any (scalar or vector) linear
secret sharing schemes. We prove a lower bound on the repair bandwidth of
secure repair schemes and show that the proposed secure repair schemes achieve
the optimal repair bandwidth up to a small constant factor when dominates
, or when the secret sharing scheme being repaired has optimal rate. We
adopt a formal information-theoretic approach in our analysis and bounds. A
main idea in our schemes is to allow a more flexible repair model than the
straightforward one-round repair model implicitly assumed by existing secure
regenerating codes. Particularly, the proposed secure repair schemes are simple
and efficient two-round protocols
Security in Locally Repairable Storage
In this paper we extend the notion of {\em locally repairable} codes to {\em
secret sharing} schemes. The main problem that we consider is to find optimal
ways to distribute shares of a secret among a set of storage-nodes
(participants) such that the content of each node (share) can be recovered by
using contents of only few other nodes, and at the same time the secret can be
reconstructed by only some allowable subsets of nodes. As a special case, an
eavesdropper observing some set of specific nodes (such as less than certain
number of nodes) does not get any information. In other words, we propose to
study a locally repairable distributed storage system that is secure against a
{\em passive eavesdropper} that can observe some subsets of nodes.
We provide a number of results related to such systems including upper-bounds
and achievability results on the number of bits that can be securely stored
with these constraints.Comment: This paper has been accepted for publication in IEEE Transactions of
Information Theor
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,
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