Secure and unprotected connections simultaneously.

[Vladislav Kolodiev]

Is it possible on the central device to create secure and unprotected connections simultaneously with different peripheral devices? How should the peer manager be configured in this case?

[Simon]

I have not done this myself, and couldn't find any other cases where people have done (after a quick search). However, I think this should be possible. In the central (or the peripheral), you simply call pm_conn_secure(), and provide the connection handle for the link you want to establish an encryption on. You also have to implement the steps explained in Peer Manager - Usage.

If you aren't able to make this work, please tell me, and I'll try to put together a simple project that demonstrates it.

Best regards,

Simon

[Vladislav Kolodiev]

Hi Simon! Thanks for the answer. This is a hypothetical case. In a real device, we will have 2 types of peripheral devices: 1) devices without a display and keyboard, and 2) smartphones. For the first type, I assume to use bonding (LESC with numerical comparison). For smartphones - use bonding : passkey entry, user inputs on peripheral. Also, smartphones may not support LESC. I have a question about the peer manager settings: do I need to make a new pm_sec_params_set () call for different connection types after receiving the BLE_GAP_EVT_CONNECTED event?

[Simon]

I took a look at the Peer Manager library, and is seems like you simply call pm_sec_params_set() right before calling pm_conn_secure() (which is called when all the services are discovered). 

• pm_sec_params_set() will call sm_sec_params_set(), and assign the security parameters to  mp_sec_params in security_manager.c
• The function pm_conn_secure() calls sm_link_secure()-->link_secure(), where the last function uses new_context_get() to get the security parameters mp_sec_params

I have not tested this myself, and don't have time at the moment, due to reduces staffing in the summer holidays. I might be able to do it later on.

I would recommend you to start with the BLE Multi-link Example, modify it and add bonding, and check out if this works.

Best regards,

Simon