Quantum cryptography

Quantum cryptography uses quantum-mechanical effects to perform cryptographic tasks. Its best-known application is quantum key distribution, which can reveal eavesdropping through disturbance of quantum states.

Quantum key distribution: A method for establishing shared cryptographic keys using quantum states and authenticated classical communication. It is the best-known practical use of quantum cryptography.
Quantum information: The study of information represented and processed using quantum states and operations. It supplies the state-based language used to describe quantum cryptographic protocols.
Quantum key distribution network: A network that connects users through links or nodes supporting quantum key distribution. It extends key exchange beyond a single point-to-point quantum channel.
Quantum hacking: Attacks that exploit implementation weaknesses in quantum cryptographic systems rather than breaking ideal protocol mathematics. Real devices can leak information despite security proofs for idealized components.
BB84: A quantum key distribution protocol that encodes bits in two incompatible bases of quantum states. Its incompatible measurement bases make interception detectable.
Quantum bit: A two-level quantum system whose state can be a superposition of two basis states. Protocols encode key information in quantum bits or other two-state systems.
Quantum repeaters: Devices or protocols intended to extend quantum communication by distributing entanglement across shorter links. They address distance limits without simply amplifying unknown quantum states.
Device-independent quantum key distribution: A key-distribution approach that certifies security from observed correlations while making minimal assumptions about devices. It aims to reduce trust in the hardware used by a protocol.
Quantum entanglement: A physical relationship in which joint quantum states cannot be described as independent states of their parts. Entanglement-based protocols use correlations to test for eavesdropping.
Classical cryptography: Methods for protecting information using mathematical operations on classical data. Quantum protocols still rely on classical authentication and often complement classical encryption.

Linked from 14 pages