Editing Bell state (section)

=== Quantum cryptography ===
[[Quantum cryptography]] is the use of quantum mechanical properties in order to encode and send information safely.  The theory behind this process is the fact that it is impossible to measure a quantum state of a system without disturbing the system.  This can be used to detect eavesdropping within a system.

The most common form of [[quantum cryptography]] is [[quantum key distribution]].  It enables two parties to produce a shared random secret key that can be used to encrypt messages.  Its private key is created between the two parties through a public channel.<ref name="Nielsen-2010" />

Quantum cryptography can be considered a state of entanglement between two multi-dimensional systems, also known as two-[[qudit]] (quantum digit) entanglement.<ref name="Sych-2009" />