This paper presents P3S, a publish-subscribe middleware designed to protect the privacy of subscriber interest and confidentiality of published content. P3S combines recent advances in cryptography, specifically Ciphertext Policy Attribute Based Encryption (CP-ABE) and Predicate Based Encryption (PBE) with an innovative architecture to achieve the desired level of privacy. An initial P3S prototype has been implemented on top of a COTS JMS platform (ActiveMQ). Results of preliminary security analysis and initial evaluation of latency and throughput indicate that the P3S design is both practical and flexible to provide different levels of privacy for publish-subscribe messaging over various message sizes and network bandwidth settings.