Broadcast channels with confidential messages

Absrfucr-Given two discrete memoryless channels @MC’s) with a common input, it is desired to transmit private messagea to receiver 1 at r&R, andcommon meswgea to both receivers at rate R,, while keeping receiver 2 as ignorant of tbe private messages as possible. Measurhg ignorance by equivocation, a single-letter characterization is given of the. achievable trfplea (RI&R,-,) where 4 is the equivocation rate. Based on this channel ding result, the related source-channel matdng problem is also settled. l%ese results generahe those of Wyner on the wiretap channel and of Kiirner-Marton on tke broahxst channel.