ENUM (telephone number mapping) is a key enabler in the convergence between IP-based networks and the traditional PSTNs that may result in additional complexity in commercial relationships and regulation of the telecommunications sector. In particular, the current ENUM may significantly increase the risk of unscrupulous use of the information managed (e.g., public user identifiers and user/service reachability). The aim of this article is to describe a new functional reference model for ENUM, and provide some new requirements that enable user privacy and security.