Quantum key distribution is a safe way to communicate using quantum mechanics cryptographic protocols. Disturbing a quantum system affects it measurably, so any attempt to eavesdrop or obtain encryption keys will alert legitimate users.

How Quantum Key Distribution Functions

  1. Generation process: The parties employ a specially designed network to produce a steady flow of photons (particles of light).
  2. Encoding: Every photon is encoded randomly using a particular quantum state depending on the range of the key bit (0 or 1) to be transmitted.
  3. Transmission: A single party sends the encoded photons to another via a transmission channel, including an optical fiber.
  4. Measurement: The recipient party uses specialized detectors to measure the quantum states of the photons randomly, allocating every photon a value of 0 or 1.
  5. Comparison: Both parties compare a segment of their measurement results across a different transmission channel. A match of the results indicates that the quantum key distribution channel is protected. On the other hand, inconsistencies lead to the termination of the key exchange procedure.
  6. Distillation: Parties perform privacy enhancement and error correction protocols to separate the last joint encryption key from the measurement results. This removes any data that third parties could have acquired during the key exchange.
  7. Communication: To safeguard their transmissions, parties may now use symmetric encryption techniques using a joint encryption key.

Applications of Quantum Key Distribution