GENERALIZED PRIVACY AMPLIFICATION

This paper provides a general treatment of privacy amplification by pu blic discussion, a concept introduced by Bennett, Brassard, and Robert for a special scenario, Privacy amplification is a process that allow s two parties to distill a secret key from a common random variable ab out which an eavesdropper has partial information, The two parties gen erally know nothing about the eavesdropper's information except that i t satisfies a certain constraint, The results have applications to unc onditionally secure secret-key agreement protocols and quantum cryptog raphy, and they yield results on wiretap and broadcast channels for a considerably strengthened definition of secrecy capacity.