Avoid "Bluetooth pairing request" alert on iOS

[Kasper Leonhardt]

Hi.

I have an application that needs a low security encryption. Therefore I want to use "Just works" encryption. The pairing process is assumed to be in a "safe" place.

But iOS are prompting with the "Bluetooth pairing request" alert before every connection. And I thing that it is very annoying and irrelevant. I can accept the first alert, but not later.

I am using 7.2 softdevice on a nRF 51822.

Is it possible to suppress this message either from the BLE device (or perhaps in the iOS App).

Kasper

[shibshab]

This page describes what parameters needs to be set in order for the peripheral to use Just Works.

When this is used correctly you should not get a prompt from iOS regarding the pairing request.

[shibshab]

Taking the UART example in 8.0 as an example. The necessary steps to enable Just Works encryption is:

• Set SEC_PARAM_BOND to 0
• For characteristics (read/write) set BLE_GAP_CONN_SEC_MODE_SET_ENC_NO_MITM

Note that RX characteristic is WriteWithoutResponse, which will not allow you to verify using a sniffer that authentication is required. Set it to write by removing the line setting write_wo_resp to 1.

Also note that this requires support on the iOS side (the nRF Toolbox app will not support this setup).