Security is one of the major issues in MANETs. Their natural characteristics make them vulnerable to numerous severe attacks. It is widely acknowledged that cryptography provides a set of strong techniques against most vulnerabilities. Several cryptographic mechanisms for MANETs can be found in the literature. Among them, identity-based cryptographic mechanisms and key management schemes are proposed to simplify key management and to reduce the memory storage cost. This article presents the most important ID-based key management schemes, discussing their approaches, strengths, and weaknesses, and comparing their main features. It also presents the main ID- based key management application fields on MANETs. In this way it can be useful for users and researchers as a starting point on ID-based key management and its possible uses in MANETs.