Today’s Internet is based on the exchange of classical bits. The key idea of the Quantum Internet is to extend this classical Internet with quantum communication, which is based on the exchange of quantum bits (qubits). A quantum internet offers a number of important (networking) applications, including defense against eavesdroppers (also if they own a quantum computer), clock synchronization, distributed consensus, and secure identification. 

These applications are based on fundamental properties of qubits, which unlike regular bits can be in a superposition of 0 and 1 at the same time. Qubits cannot be copied, and any attempt to read the state of a qubit can be detected. Furthermore, two qubits can be entangled, which forms the basis for ‘teleporting’ shared (quantum) state across devices, which in turn is a key ingredient of many quantum communication applications.