Based on periodically poled lithium niobate, a scheme for optical signal temporal cloak and encryption in the optical physical layer is proposed and numerically studied, in which the amplitude and phase information of the symbols to be sent are detected and transmitted while that of all other symbols will be hidden from the receiver. Meanwhile, the phase and amplitude of the symbols that are not hidden can be encrypted according to arbitrary encryption rules in the optical physical layer. The simulation results show that there is almost no ripple in the cloak time window, which makes the performance of temporal cloak quite well. The output signals with high Q factor can be obtained when the linewidths of the tunable lasers are <300 kHz. Two simple encryption rules are designed, 43.75% of binary codes will be misinterpreted by eavesdropper if the signal is encrypted with such two rules in the demonstration.