This document provides a summary of key challenges and approaches for key management in mobile ad hoc networks (MANETs). It discusses how MANETs have dynamic topologies and limited resources, posing security challenges. It reviews how cryptography is used to provide security but requires effective key management. It surveys research on asymmetric, symmetric, and group key management schemes proposed for MANETs. It also discusses trust models for key distribution, including centralized models using a trusted third party and decentralized models without a central authority.