Abstract: A method and apparatus capable of identifying a unique user across multiple devices in a computer network are provided. Device-specific and behavioral features associated with an event and a device are extracted. The device-specific features form a device signature associated the device. Hardware mobile device identifiers (IDs) are also associated with mobile application devices. Over a period of time, the behavioral features of such devices are monitored. Similarity scores between various devices are calculated based on the behavioral features and device types. The devices in the computer network are clustered and a device graph is generated representing the connections between the devices based on the similarity scores. A unique user ID associated with the multiple devices is generated from the device graph.