  In the classical Secret-Key generation model, Common Randomness is generated
by two terminals based on the observation of correlated components of a common
source, while keeping it secret from a non-legitimate observer. It is assumed
that the statistics of the source are known to all participants. In this work,
the Secret-Key generation based on a compound source is studied where the
realization of the source statistic is unknown. The protocol should guarantee
the security and reliability of the generated Secret-Key, simultaneously for
all possible realizations of the compound source. A single-letter lower-bound
of the Secret-Key capacity for a finite compound source is derived as a
function of the public communication rate constraint. A multi-letter capacity
formula is further computed for a finite compound source for the case in which
the public communication is unconstrained. Finally a single-letter capacity
formula is derived for a degraded compound source with an arbitrary set of
source states and a finite set of marginal states.
