Parece que a partir del 10.14 Apple son sigue usando Milenrama.

La fuente de xnu-4903.221.2/osfmk/prng/random.h dice "...retenemos a Yarrow. " y el código posterior está condicionado a que Flecha esté codificada como verdadera:

void early_random_cpu_init(int cpu);

/*
 * Wrapper for requesting a CCKPRNG operation.
 * This macro makes the DRBG call with pre-emption disabled to ensure that
 * any attempt to block will cause a panic. And the operation is timed and
 * cannot exceed 10msec (for development kernels).
 * But skip this while we retain Yarrow.
 */
#define YARROW 1
#if YARROW
#define PRNG_CCKPRNG(op) \
    MACRO_BEGIN          \
    op;                  \
    MACRO_END
#else

Suponiendo que esté actualizado, man random en 10.14.5 lo confirma:

 The random device implements the Yarrow pseudo random number generator algorithm and maintains
 its entropy pool.  The kernel automatically seeds the algorithm with additional entropy during
 normal execution.

Si la Milenrama es suficiente o no, parece que está contemplada en su otra pregunta .