A New Symmetric Key Quantum Cryptographic Algorithm

Based on the principles of both classical and quantum computation primitives, a new symmetric key quantum cryptographic algorithm is proposed. This algorithm can be used to encrypt classical binary messages as well as quantum information. Encryption and decryption are implemented by the aid of classical and quantum computation which can be realized by suitable technology. Because each encryption process is under the control of the key which is dynamically and recursively changed through each round in both encryption and decryption and the final ciphertext states are non-orthogonal, the eavesdropper can not acquire fixed ciphertext without the keys so the eavesdropping attack is invalid, which is guaranteed with the no-cloning theory in quantum mechanics. Similarly, the non-orthogonality of the ciphertext renders the Trojan horse attack strategy impossible. Also the algorithm applies a pseudo random process from stage to stage. This pseudo randomness hinders the ability of Eve to attack such a cryptographic scheme.