General Quantum Encryption Scheme Based on Quantum Memory

In cryptography, quantum information processing can be used to do much more than just key distribution. Simple quantum transformations augmented with the ability to store qubits in a quantum memory are the building blocks of a protocol allowing two parties to communicate secretly by encoding/decoding the exchanged message directly through quantum means, without the need to establish a secret encryption/decryption key first. Consequently, our quantum mechanical process of securely transmitting a message through a public channel is simpler, cleaner, faster and computationally more efficient than the twostep scenario with a quantum distributed classical key. The probability of catching a potential eavesdropper can be made arbitrarily large by increasing the length of the signature string attached to the message.