Abstract: We report an ReRAM-based pseudo-true random number generator (RNG) which can significantly improve the security feature of e-ReRAM chips at a very low cost. Combining the true randomness from stochastic behavior of ReRAM and the high output speed from a modified linear feedback shift register (LFSR), the proposed architecture can provide ultrahigh throughput random sequence following system clocks from several Mbit/sec to tens of Gbit/sec. The highly reliable, unpredictable, and unrepeatable ReRAM-based pseudo-true RNG circuit can pass NIST SP800-22 randomness tests at a high score. It is suitable for secure IoT and 5G applications.