Protocol and applications for sharing quantum private keys

Transmitting message in secret is getting more and more important nowadays. In the classical world, the message we sent run the risk of being intercepted by an attacker. As a result, we have to encrypt the message, or send it using a private channel. However, if we transmit messages via such methods, there are still some ways to decipher the information. For example, a powerful computer can be used to decrypt the message or try to steal the message from the private channel. In quantum cryptography, entanglement can be used as a secure channel to transmit information with absolute secrecy. From this perspective, quantum entanglement pairs are equivalent to a quantum private key. However, like the classical key distribution problem, the entanglement has to be shared before it can be used. In this paper, we propose a protocol that can be used to distribute such entanglement pairs securely, so they can be subsequently used to transmit messages with perfect security. The security of this protocol is based on the laws of nature, instead of unproven mathematical hard problems.