  Quantum cryptography -- the application of quantum computing techniques to
cryptography has been extensively investigated. Two major directions of quantum
cryptography are quantum key distribution (QKD) and quantum encryption, with
the former focusing on secure key distribution and the latter focusing on
encryption using quantum algorithms. In contrast to the success of the QKD, the
development of quantum encryption algorithms is limited to designs of mostly
one-time pads (OTP) that are unsuitable for most communication needs. In this
work we propose a non-OTP quantum encryption scheme utilizing a quantum state
creation process to encrypt messages. As essentially a non-OTP quantum block
cipher the method stands out against existing methods with the following
features: 1. complex key-ciphertext relation (i.e. confusion) and complex
plaintext-ciphertext relation (i.e. diffusion); 2. mode of operation design for
practical encryption on multiple blocks. These features provide key reusability
and protection against eavesdropping and standard cryptanalytic attacks.
