Demonstrating BB84 Quantum Key Distribution in the Physical Layer of an Optical Fiber Based System

Nowadays, widely spread encryption methods (e.g., RSA) and protocols enabling digital signatures (e.g., DSA, ECDSA) are an integral part of our life. Although recently developed quantum computers have low processing capacity, huge dimensions and lack of interoperability, we must underline their practical significance – applying Peter Shor’s quantum algorithm (which makes it possible to factorize integers in polynomial time) public key cryptography is set to become breakable. As an answer, symmetric key cryptography proves to be secure against quantum based attacks and with it quantum key distribution (QKD) is going through vast development and growing to be a hot topic in data security. This is due to such methods securely generating symmetric keys by protocols relying on laws of quantum physics.