[Cryptech Tech] About the TRNG

[Jacob]

A question to the experts:

I fully understand the trust gained by having a custom made external 
analog TRNG as we do here, but wouldn't be better to XOR the bitstream 
received from our generator with the one embedded in the CPU(*)? I mean, 
if the CPU 's TRNG is tainted, we will not be worse off, and if it is 
not, the board will probably exhibit higher security in case our 
generator would have some issues.

(*) from the STM32F429 datasheet: All devices embed an RNG that delivers 
32-bit random numbers generated by an integrated analog circuit
(analog noise feeding into a shift register)