A graph data model represents an environment as connected nodes and edges. In identity security, the nodes are often users, groups, computers, services, and permissions, while the edges describe relationships such as membership, delegation, login rights, or inherited access. This is different from a flat list or spreadsheet because it shows how one relationship can lead to another.
Graph models matter because attackers look for privilege chains, not just obvious admin accounts. A low-privilege user may reach sensitive systems through several small, valid permissions that only become risky when combined. Defenders use graph analysis to find those hidden paths, spot excessive access, reduce privilege creep, and verify that least-privilege policies work in practice. Tools like BloodHound rely on this approach to make complex identity relationships easier to investigate.