Zero Trust Network Access is a security model that does not assume a user, device, or session is safe just because it is inside the network. Instead, every request must be verified against identity, device posture, policy, and context before access is granted. ZTNA usually replaces broad network VPN access with per-application access controls.
ZTNA matters because many attacks succeed after an initial login or device compromise. If an attacker steals credentials, ZTNA can still block access when the device is unmanaged, the request is unusual, or the user lacks permission for that app or data. In cloud and browser-based workspaces, ZTNA helps defenders enforce least privilege, reduce lateral movement, and log each decision. It also fits AI platforms, where agent requests, tool calls, and data access should be checked before the model can act.