kvantvõtmejaotus

kvantvõtmejaotus, often abbreviated as QKD, is a secure communication method that uses quantum mechanics to establish a shared secret key between two parties. This key can then be used for encrypting and decrypting messages. Unlike traditional cryptography, which relies on the mathematical difficulty of certain problems, QKD's security is based on the fundamental laws of physics.

The core principle of kvantvõtmejaotus involves sending single photons, the quantum particles of light, from one party (Alice) to another (Bob). Each photon is encoded with a bit of information, either a 0 or a 1, by its polarization state. Alice can prepare photons in different polarization states, and Bob measures these states.

A crucial aspect of QKD is that any attempt by an eavesdropper (Eve) to intercept or measure the photons will inevitably disturb their quantum state. This disturbance can be detected by Alice and Bob, alerting them to the presence of an eavesdropper. If a significant disturbance is detected, they discard the compromised key and attempt to establish a new one.

Several protocols exist for kvantvõtmejaotus, with the BB84 protocol being one of the earliest and most well-known. These protocols differ in how they encode and transmit quantum information. The distance over which QKD can be effectively implemented is currently limited by photon loss in optical fibers or free space. Despite these limitations, kvantvõtmejaotus represents a significant advancement in secure communication, offering a theoretically unbreakable method for key distribution.