Secret key agreement under sampling attack

This paper considers the capacity for secret key agreement under a sampling attack. Given the number of the eavesdropper´s sources, we evaluate the secret key capacity bound which is defined as the supremum of the secret key capacity divided by the description length of the alphabet, where the supremum is taken over a set of probability distributions corresponding to the correlated sources. In particular, we consider symmetric sources and permutation-invariant sources. We derive inequalities which show the scaling of the secret key capacity bound with the number of the eavesdropper´s sources