Though the MANET concept exists for decades and that many researches were carried out, such networks suffer from extremely low adoption. The main reason is the security or more precisely, lack thereof. This paper defines what a MANET should be for a real use, it explains what are the security challenges and analyzes the problems of the existing proposals to secure such network. Our main assumption is that security problems as we expose them should be addressed globally and not in a fragmented manner as currently. This paper aims at defining a state of the art that will be useful to propose a practical and global solution.