nrf_ecb_crypt() transmits waste chars

RE: nrf_ecb_crypt() transmits waste chars

MartinBL — Tue, 23 Jan 2018 09:02:36 GMT

Great! Happy to help.

RE: nrf_ecb_crypt() transmits waste chars

Hase — Tue, 23 Jan 2018 01:38:06 GMT

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

RE: nrf_ecb_crypt() transmits waste chars

MartinBL — Fri, 19 Jan 2018 07:38:16 GMT

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.

RE: nrf_ecb_crypt() transmits waste chars

Hase — Fri, 19 Jan 2018 00:16:47 GMT

Thank you for your reply. But replacing it with the following results the same.

    uint8_t crypt[17];
    crypt[16] = 0;

And I never transmit the result in crypt explicitly.

I wonder why characters is transmitted.

Thanks.

RE: nrf_ecb_crypt() transmits waste chars

Andre — Thu, 18 Jan 2018 09:23:08 GMT

The text you have in your string is 16 bytes long. This means the null terminator is the 17th byte. Thus this 17th byte is not in the encrypted string. If you decrypt it, you need to be aware the result is not null-terminated. So, you must only print 16 characters. If you would like to just use a printf, you should have the string 15 characters, such that the 16th byte is the null terminator.