  We study the information leakage to a guessing adversary in index coding with
a general message distribution. Under both vanishing-error and zero-error
decoding assumptions, we develop lower and upper bounds on the optimal leakage
rate, which are based on the broadcast rate of the subproblem induced by the
set of messages the adversary tries to guess. When the messages are independent
and uniformly distributed, the lower and upper bounds match, establishing an
equivalence between the two rates.
