You should get a status json response.
In OpenEnclave, the oe_random() function is used to generate random numbers. This function uses the RDRAND instruction, if available, to generate entropy from the processor's hardware random number generator (RNG).
If the RDRAND instruction is not available, the function uses the operating system's random number generator.
The oe_random() function is used to generate keys, nonces, and other random data in OpenEnclave. Mbedtls should normally calls to RDRAND instruction when calling to a random number generator.
AES generation key
While generating an AES 256 bits key, a strong entropy source and seed the DRBG with sufficient entropy to ensure that the generated key must be used. This gives you the property of a cryptographically secure generated key.