In one embodiment, a method comprises receiving a unique identifier from an item and sending a communication to an electronic device requesting that a user confirm a pending transaction, receiving input from the electronic device associated, and sending the received input to an authentication system for completing a transaction. In another embodiment, a system comprises a sensor, an authentication system, and a transaction processing system. The sensor is configured to emit energy and receive at least one first identifier, send at least one communication to an electronic device requesting a second identifier, receive at least one second identifier, and send the at least one first identifier and the at least one second identifier to the authentication system. The authentication system is configured to receive the at least one first and second identifiers from the sensor, to choose, based on the at least one first identifier and the at least one second identifier, a transaction processing system, and send the at least one first and second identifiers to the chosen transaction processing system.