Quantum key distribution is a method of securely exchanging a symmetric key from afar. Once you have that symmetric key, you encode your message with the key (s

Quantum key distribution is a method of securely exchanging a symmetric key from afar. Once you have that symmetric key, you encode your message with the key (say using a one-time pad), and send it via a classical channel as usual, and the other person decodes it. So what could happen is that that every month you could have a session with your bank to exchange a 100MB secure key using quantum key distribution. Then during the month, you and the bank could use regular internet to communicate securely using the key.