To analyze the security of tangent-delay ellipse reflecting cavity-map system (TD-ERCS) from the point view of cryptography, a simple pseudo-random number generator (PRNG) is proposed with parallel TD-ERCS in this paper. Users' keys are n o longer fixed, and can be chosen in the interval [264, 26 72] arbitr arily in the PRNG. By testing the basic statistic characteristics such as equili brium, runs and correlation of the binary pseudo-random sequences (viz. TD-ERCS sequences) being generated from the PRNG, and comparing with m-sequences, the lo gistic sequences, Chebyshev sequences and SCQC sequences, the experimental resul ts show that TD-ERCS sequences have better statistic characteristics.