Editing Quantum information (section)

==== Development from cryptography ====
{{See also|Quantum cryptography}}
Despite all the excitement and interest over studying isolated quantum systems and trying to find a way to circumvent the theory of relativity, research in quantum information theory became stagnant in the 1980s. However, around the same time another avenue started dabbling into quantum information and computation: [[Cryptography]]. In a general sense, ''cryptography is the problem of doing communication or computation involving two or more parties who may not trust one another.''<ref name="Nielsen2010" />

Bennett and Brassard developed a communication channel on which it is impossible to eavesdrop without being detected, a way of communicating secretly at long distances using the [[BB84]] quantum cryptographic protocol.<ref name="Bennett2014"/> The key idea was the use of the fundamental principle of quantum mechanics that observation disturbs the observed, and the introduction of an eavesdropper in a secure communication line will immediately let the two parties trying to communicate know of the presence of the eavesdropper.