This document proposes algorithms for distributing malware signatures across mobile devices to optimize detection and recovery from infections. It describes a greedy algorithm that selects signatures to maximize a "system welfare" metric accounting for individual device utilities. It also describes an encounter-based distributed algorithm where devices exchange signatures opportunistically. Simulation results show the distributed algorithm approaches the performance of the greedy algorithm over time under different mobility models. The goal is to minimize the number of infected devices by optimally distributing signatures across a network of helpers considering device and malware heterogeneity.