Sor, I'll make it clearer.
Imagine a scene, my board has a AES function that generates cipher of a given plaintext.
Now I connect my board to my PC using debug link, and I want the board to listen to PC's messages that give to the board by UART as plaintext.
And since the key for AES is generated by PUF related functions on board, I have to store the key into the board itself.
How can I meet such requirements?