In theory, quantum cryptography can provide unconditional secure communication between two trustful parties. However, the imperfect devices may leave loopholes for various hackings in practical implementations. In this talk, I shall discuss the solutions to close these loopholes and present a couple of experiments recently achieved by our group, including: passive decoy QKD and measurement device independent QKD. Meanwhile, I will present an ultra-new type of quantum cryptography experiment, unconditional secure bit commitment, a secure communication between two mistrustful parties.