I want to utilize the libraries already located within the firmware to encrypt data sent across multiple photons. After looking through the firmware, I noticed that the rsa key gen file (firmware/crypto/mbedtls/programs/pkey/rsa_genkey.c) creates the key and stores it in rsa_pub.txt. How do I go about accessing this file after flashing the firmware to my photon? Is this possible? If not, should I just copy the key gen file to create a key in memory, or can I somehow create my own file to hold it?