2 research outputs found
Key Agreement over an Interference Channel with Noiseless Feedback: Achievable Region & Distributed Allocation
Secret key establishment leveraging the physical layer as a source of common
randomness has been investigated in a range of settings. We investigate the
problem of establishing, in an information-theoretic sense, a secret key
between a user and a base-station (BS) (more generally, part of a wireless
infrastructure), but for two such user-BS pairs attempting the key
establishment simultaneously. The challenge in this novel setting lies in that
a user can eavesdrop another BS-user communications. It is thus paramount to
ensure the two keys are established with no leakage to the other user, in spite
the interference across neighboring cells. We model the system with BS-user
communication through an interference channel and user-BS communication through
a public channel. We find the region including achievable secret key rates for
the general case that the interference channel (IC) is discrete and memoryless.
Our results are examined for a Gaussian IC. In this setup, we investigate the
performance of different transmission schemes for power allocation. The chosen
transmission scheme by each BS essentially affects the secret key rate of the
other BS-user. Assuming base stations are trustworthy but that they seek to
maximize the corresponding secret key rate, a game-theoretic setting arises to
analyze the interaction between the base stations.We model our key agreement
scenario in normal form for different power allocation schemes to understand
performance without cooperation. Numerical simulations illustrate the
inefficiency of the Nash equilibrium outcome and motivate further research on
cooperative or coordinated schemes.Comment: A shorter version of this paper was presented at CNS 201
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
Information Theor