Real-Time TRNG Health Monitoring with Higher-Order Proportion Testing and Rotating Pattern Detection at 500 MHz on FPGA

True Random Number Generators (TRNGs) are critical components in cryptographic systems, yet their statistical quality can degrade due to environmental variations, aging, or adversarial interference. Existing health monitoring solutions typically implement only the mandatory tests defined by NIST SP 800-90B, and rarely achieve real-time streaming operation at high clock rates. This paper presents a fully pipelined, eight-test health monitoring architecture for TRNGs, implemented on FPGA with a clock period of 2 ns (500 MHz), processing every output bit in a continuous streaming fashion without data buffering. The proposed architecture introduces two novel contributions. First, a Higher-Order Adaptive Proportion Test (HO-APT) family that generalizes the standard NIST APT from single-bit to multi-bit tuple analysis (APT-1, APT-2 and APT-3), enabling detection of inter-bit statistical dependencies that remain invisible to conventional proportion testing. Second, a Rotating Pattern Detector that time-multiplexes pattern scanning across the full pattern space, achieving complete structural coverage within 67 MS using minimal hardware resources — a capability absent from existing streaming monitors. The remaining tests (RCT, bias estimator, and correlation estimator) complement these two contributions to form a three-layer defense: immediate fault detection, statistical distribution monitoring, and structural pattern surveillance. All thresholds conform to NIST SP 800-90B requirements. Experimental results on FPGA confirm timing closure at 2 ns clock period with modest resource utilization.