3 research outputs found
Rate Regions of Secret Key Sharing in a New Source Model
A source model for secret key generation between terminals is considered. Two
users, namely users 1 and 2, at one side communicate with another user, namely
user 3, at the other side via a public channel where three users can observe
i.i.d. outputs of correlated sources. Each of users 1 and 2 intends to share a
secret key with user 3 where user 1 acts as a wiretapper for user 2 and vice
versa. In this model, two situations are considered: communication from users 1
and 2 to user 3 (the forward key strategy) and from user 3 to users 1 and 2
(the backward key strategy). In both situations, the goal is sharing a secret
key between user 1 and user 3 while leaking no effective information about that
key to user 2, and simultaneously, sharing another secret key between user 2
and user 3 while leaking no effective information about the latter key to user
1. This model is motivated by wireless communications when considering user 3
as a base station and users 1 and 2 as network users. In this paper, for both
the forward and backward key strategies, inner and outer bounds of secret key
capacity regions are derived. In special situations where one of users 1 and 2
is only interested in wiretapping and not key sharing, our results agree with
that of Ahlswede and Csiszar. Also, we investigate some special cases in which
the inner bound coincides with the outer bound and secret key capacity region
is deduced
A New Secret key Agreement Scheme in a Four-Terminal Network
A new scenario for generating a secret key and two private keys among three
Terminals in the presence of an external eavesdropper is considered. Terminals
1, 2 and 3 intend to share a common secret key concealed from the external
eavesdropper (Terminal 4) and simultaneously, each of Terminals 1 and 2 intends
to share a private key with Terminal 3 while keeping it concealed from each
other and from Terminal 4. All four Terminals observe i.i.d. outputs of
correlated sources and there is a public channel from Terminal 3 to Terminals 1
and 2. An inner bound of the "secret key-private keys capacity region" is
derived and the single letter capacity regions are obtained for some special
cases.Comment: 6 pages, 3 figure
Strong Secrecy in Pairwise Key Agreement over a Generalized Multiple Access Channel
This paper considers the problem of pairwise key agreement without public
communication between three users connected through a generalized multiple
access channel (MAC). While two users control the channel inputs, all three
users observe noisy outputs from the channel and each pair of users wishes to
agree on a secret key hidden from the remaining user. We first develop a
"pre-generated" key-agreement scheme based on secrecy codes for the generalized
MAC, in which the channel is only used to distribute pre-generated secret keys.
We then extend this scheme to include an additional layer of rate-limited
secret-key generation by treating the observed channel outputs as induced
sources. We characterize inner and outer bounds on the strong secret-key
capacity region for both schemes. For a special case of the "pre-generated"
scheme, we obtain an exact characterization. We also illustrate with some
binary examples that exploiting the generalized nature of the generalized MAC
may lead to significantly larger key-agreement rates.Comment: 45 pages, 11 figures, Submitted to the IEEE Transactions on
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