nrf_ecb_crypt() transmits waste chars

[Hase]

Hi,

I'm trying using AES ECB encryption of peripheral drivers on development board with nRF52832 and PCA10040.

I inserted the following code before main loop of ble_app_uart sample in nRF5 SDK version 12.2.

#define SRC ((uint8_t *)"sample 16B text.")
#define AES_KEY ((uint8_t *)"abcdefgh12345678")

int main (void) {
    ...
    uart_init();
    ret = nrf_ecb_init();

    ...
    uint8_t crypt[16];
    nrf_ecb_set_key(AES_KEY);
    ret = nrf_ecb_crypt(crypt, SRC);

    for(;;)
    {
        ...

In case that there isn't the last line of nrf_ecb_crypt() before for(;;), it works well. But add it and only waste characters comes on to terminal emulator.

Why it behaves so?

Thanks

[MartinBL]

Hi,

Are you using a Softdevice while your are doing this? If you are using a Softdevice the ECB is a restricted resource, and hence should use a sd_ecb_xx API calls if you want to use it. It is a bit strange though, that you would only get garbage data and not more serious problems if this was the cause.

[Hase]

sd_ecb_block_encrypt() seems to work expectedly. Thanks a lot!

[MartinBL]

Great! Happy to help.