/**
* \brief Generate AES sub key
*
* Get AES sub key by encryption of dummy data.
*
* \param key Pointer to AES key input.
* \param last_sub_key Pointer to AES sub key output.
*
*/
static bool aes_lastsubkey_generate(t_key key, t_key last_sub_key)
{
bool keygen_ok;
aes_software_reset();
/* Set AES encryption of a single block in manual mode. */
aes_configure(AES_ENCRYPT, AES_MANUAL, AES_XOR_OFF);
/* Load key into AES key memory. */
aes_set_key(key);
/* Load dummy data into AES state memory. It isn't important what is
* written, just that a write cycle occurs. */
aes_write_inputdata(dummy_data);
/* Start encryption. */
aes_start();
do {
/* Wait until AES is finished or an error occurs. */
} while (aes_is_busy());
/* If not error. */
if (!aes_is_error()) {
/* Store the last subkey. */
aes_get_key(last_sub_key);
aes_clear_interrupt_flag();
keygen_ok = true;
} else {
aes_clear_error_flag();
keygen_ok = false;
}
return keygen_ok;
}
/**
* \brief Test AES get and set key value functions.
*
* This test sets a key in the AES module, and reads it back with
* the get function.
*
* \param test Current test case.
*/
static void run_aes_set_and_get_key_test(const struct test_case *test)
{
t_key read_key;
bool success;
set_buffer(read_key, 0x00);
/* Reset the module */
aes_software_reset();
aes_set_key(encryption_key);
aes_get_key(read_key);
/* Check if read_key is the same as what was set */
success = compare_data_block(encryption_key, read_key);
test_assert_true(test, success,
"Key read from AES module is not as set");
}
/**
* \brief Generate AES sub key
*
* \note Get AES sub key by encryption of dummy data.
*
* \param key Pointer to AES key input.
* \param last_sub_key Pointer to AES sub key output.
*
*/
static bool aes_lastsubkey_generate(t_key key, t_key last_sub_key)
{
bool keygen_ok;
uint8_t i;
/* Before using the AES it is recommended to do an AES software reset to
* put the module in known state, in case other parts of your code has
* accessed the AES module. */
aes_software_reset();
/* Set AES encryption of a single block in manual mode. */
aes_configure(AES_ENCRYPT, AES_MANUAL, AES_XOR_OFF);
/* Load key into AES key memory. */
aes_set_key(key);
/* Load dummy data into AES state memory. */
for (i = 0; i < BLOCK_LENGTH; i++) {
AES.STATE = 0x00;
}
/* Start encryption. */
aes_start();
do {
/* Wait until AES is finished or an error occurs. */
} while (aes_is_busy());
/* If not error. */
if (!aes_is_error()) {
/* Store the last subkey. */
aes_get_key(last_sub_key);
aes_clear_interrupt_flag();
keygen_ok = true;
} else {
aes_clear_error_flag();
keygen_ok = false;
}
return keygen_ok;
}