Kvantumkriptográfia

Kvantumkriptográfia, also known as quantum cryptography, is a field that utilizes the principles of quantum mechanics to perform cryptographic tasks. The most prominent application of quantum cryptography is in secure key distribution, often referred to as quantum key distribution (QKD). QKD allows two parties to generate and share a secret random key known only to them, which can then be used for encrypting and decrypting messages using classical cryptographic methods.

The security of QKD relies on the fundamental laws of quantum physics. Specifically, it leverages the fact that measuring a quantum system inevitably disturbs it. In QKD protocols, information is encoded into quantum states, such as the polarization of photons. If an eavesdropper attempts to intercept and measure these quantum states, they will inevitably introduce detectable errors, alerting the legitimate users to the presence of an intrusion. This property provides a level of security unattainable with classical cryptography, where eavesdropping can often go undetected.

One of the most well-known QKD protocols is BB84, named after its creators Charles Bennett and Gilles Brassard. It uses polarized photons to transmit bits of the key. While QKD offers theoretical security advantages, practical implementations face challenges related to distance limitations, noise, and the cost of specialized hardware. Despite these hurdles, research and development in quantum cryptography are ongoing, with the aim of building more robust and scalable quantum communication networks. The potential implications of quantum computing for breaking current encryption methods also drive interest in quantum-resistant cryptography, including quantum key distribution.