Quantum cryptography

Another possible application of quantum entanglement is quantum cryptography. The idea is that, in quantum mechanics, the idea of measuring a system disturbs it. Thus, if a third party or eavesdropper were attempting to see a private message, this eavesdropping could be detected by the disturbance that its observation created on the quantum system. Observations of quanta change their behavior. For example, in the Heisenberg uncertainty principle, examining the velocity changes the position and vice-versa of a particle. Also, because of the no-cloning theorem, it would be impossible for the eavesdropper to make a copy of the unknown quantum state. This disturbance would be able to be detected.