This paper describes an extension to the Internet Backplane Protocol (IBP), called Content-addressable IBP (IBPCA). IBP is an important protocol in distributed, Web, Grid and peer-to-peer computing settings, as it allows clients in these settings to access, manipulate and manage remote storage depots in a scalable and fault-tolerant fashion. Content-addressability adds the ability to reference storage by hashes of its contents. In this paper, we discuss the rationale behind IBPCA, important design decisions, and performance implications.