Quantum cryptography Quantum secure direct communication Quantum signature Arbitrated quantum signature Security analysis Attack Entanglement GHZ state Known message attack Quantum broadcasting multiple blind signature Quantum dialogue Quantum machine learning Semi-quantum Simultaneous dense coding -party communication Active learning Amplitude damping Bidirectional communication Complete robustness Completely robust Continuous variable Controlled bidirectional quantum direct communication Correlated noise Cosmic string spacetime Duality computers Dynamics Equivalence Problem Existential forgery Fair blind signature Fidelity