Hi,
I'm using nRF Connect SDK v1.7.1 with two nrf5430 DK. My goal is to evaluate the different security levels. For testing i send messages with the Nordic Uart service between those two boards. I used bt_conn_set_security() to increase the security level. This works fine and i can reach all 4 levels and the keys are distributed. Now my question is, if level 2, 3 or 4 is activated, does Zephyr automaticly encrypt the messages befor sending them or do i need to do this with bt_encrypt_le() or bt_ccm_encrypt() in my application? I thought bt_ccm_encrypt should be the right function because it uses AES-CCM which is defined in the BLE specification. But i can't find this function in any file. And what about security Mode 2 data signing. Is it enough to set CONFIG_BT_SIGNING or do i also have to implement bt_smp_sign() bevor calling the NUS send function? Through debugging I came to the result, that i have to implement it by myself but i can not find any example where someone else did that. Did i miss something or am i on the right track?
Hope someone can clarify that for me.