We present a formalization of Kanger's types of rights in the context of interacting two-party systems, such as contracts. We show that in this setting basic rights such as claim, freedom, power and immunity can be expressed in terms of (possibly negated) permissions and obligations over presence or absense of actions. Another way of saying this is that, at least in the context of contracts, neither claim, nor power, nor freedom nor immunity are foundational modalities, as they can be defined in terms of others. We also show that the set of atomic type rights is different from Kanger's original proposal.