Developing Custom BLE Authentication - How to protect services/characteristics

[scotzark]

Hi-

In our application we are not using pairing, but instead want to use a proprietary authentication scheme were we right a passkey to an unprotected characteristic and based on that we want to unlock the ability to read/write the other services + characteristics.  What is the best way to do this with the 17.1.0 SDK?  Is there a way to simply update the read_perm / write_perm (SEC security parameters) on the fly?  This would seem to do what we want.  When authenticated we just run SEC_OPEN, and then un-auth'd we change it to something like SEC_JUST_WORKS.  But we are wondering if there is a best practice in place for this already?

thanks,

Scot

[Kenneth]

Authorization seems to be the way to go yes, you can add authorization on both read and write, ref:
https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.s132.api.v7.3.0%2Fgroup___b_l_e___g_a_t_t_s___r_e_a_d___r_e_q___a_u_t_h___m_s_c.html 
https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.s132.api.v7.3.0%2Fgroup___b_l_e___g_a_t_t_s___w_r_i_t_e___r_e_q___a_u_t_h___m_s_c.html 
https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.s132.api.v7.3.0%2Fgroup___b_l_e___g_a_t_t_s___w_r_i_t_e___c_m_d___a_u_t_h___m_s_c.html 

I would think (hope) searching through the ble projects for sd_ble_gatts_rw_authorize_reply() can give some results.

Edit: Also check out:
RE: How to deal with the characteristic read event? 

Kenneth