We describe Divalia, a new peer?to?peer (P2P) file exchange framework that targets mobile wireless ad-hoc networks. The framework supports anonymous transfers, to protect user privacy, as well as pre-authentication of data to be received, to reduce the likelihood of spoofs and the resulting bandwidth wastage. Divalia is composed of two parts: the Hash Set Dual-Request Protocol, to challenge a would-be provider to prove the possession of the requested file; and, a form of Direct Anonymous Broadcast, for anonymous acquisition of information to be used for the challenge. One goal of this paper is to demonstrate how an original and secure P2P system can be constructed within the constraints and opportunities of mobile wireless ad- hoc networks through the use of well known and extensively studied component cryptographic methods.