Design and Analysis of a Three-Stream STT-MTJ TRNG With XOR and Majority Voter Logic as Postprocessing Architectures

True Random Number Generators (TRNGs) are critical for hardware security, providing unpredictable entropy for cryptographic applications. Spin-Transfer Torque Magnetic Tunnel Junction (STT-MTJ) devices offer a promising entropy source due to their low power consumption, non-volatility, and stochastic switching behavior. This work presents a MTJ-based TRNG which produces three independent bit streams. Two post processing architectures are investigated, (a) 3-input Majority Voter and (b) 2 input two-stage XOR logic. Both schemes are evaluated in terms of entropy enhancement, bias reduction, and hardware efficiency. Simulation results demonstrate that the XOR-based design achieves superior statistical uniformity, while the Majority Voter provides improved fault tolerance. Both post processing approaches exhibit similar energy consumption ≈ 13.4pJ/bit, while achieving an identical throughput of 25 Mbps. Randomness quality was validated using the NIST SP 800-22 test suite, and comparative analysis highlights the trade-off between entropy maximization and reliability. The study provides design insights for secure and energy-efficient TRNG implementations in post-CMOS hardware platforms.