Quasitriangular structures of the double of a finite group

We give a classification of all weak $R$-matrices on $\mathcal{D}(G)$, the Drinfeld double of a finite group $G$, over an arbitrary field. As an application we determine all quasitriangular structures and ribbon elements of $\mathcal{D}(G)$ explictly in terms of group homomorphisms and central subgroups. When the field is algebraically closed and of characteristic 0 this can equivalently be interpreted as an explicit description of all braidings of the braided fusion category $\operatorname{Rep}(\mathcal{D}(G))$.