International law can be divided into the categories of Private Law and Public Law. Private law is that part of a civil law legal system which is part of the jus commune that involves relationships between individuals, such as the law of contracts or torts, and the law of obligations. Contrastingly, public law deals with relationships between both natural and artificial persons (i.e., organizations) and the state, including regulatory statutes, penal law, and other law that effects the public order.
So, in general terms, private law involves interactions between private citizens, whereas public law involves interrelations between the state and the general population.
Public Law can be further separated into the categories of the Law of Armed Conflict and the Law of Peace.
The Law of Armed Conflict can be further separated into the categories of
Conflict Management (Jus ad Bellum) and Rules of Hostilities (Jus in Bello).
Conflict Management (Jus ad Bellum) includes the U.N. Charter, Arms Control agreements, and Customary Law.
Rules of Hostilities (Jus in Bello) includes the Hague Conventions, Geneva Conventions, and Customary Law.