A user identity authentication system in a network is implemented on a device or multiple devices in the network. The authentication system employs a map that translates device-specific user IDs to system-wide user IDs and vice versa. A user is authenticated on a device with a device-specific authentication method. Once a user is authenticated on a specific device, a device-specific user ID is translated into a system-wide user ID. This system-wide user ID is further translated into other device-specific user IDs such that other devices can authenticate the user based on the device-specific user IDs. Further, if a device is not capable of authenticating a user, it can delegate authentication to another device or a proxy.