By combining quantum key with classical one, a novel block cryptographic algorithm that can be applied to encrypt qubits is presented. The security of the algorithm is analyzed from several aspects. It is shown that the qubit block encryption algorithm can prevent quantum attacking strategy as...

Based on quantum computation, a novel quantum block cryptographic algorithm that can be used to encrypt classical messages is proposed. The security of this algorithm is analyzed from several aspects. It is shown that the quantum block cryptographic algorithm, in which the key can be reused...

We study chaotic functions that are exact solutions to nonlinear maps. A generalization of these functions (which cannot be expressed as a recursive procedure anymore) can produce truly random sequences. Even if the initial conditions are known exactly, the next values are in principle...

We give a tutorial review on the role of entanglement of quantum systems in some tasks of quantum information theory and describe in particular how it can be exploited to achieve secure communication channels.