Zephyr sample for pairing without passkey

[snowuyl]

When I set CONFIG_BT_FIXED_PASSKEY=y in prj.conf. The following warning messages are generated by west build command.

CONFIG_BT_FIXED_PASSKEY is enabled

A fixed passkey is easy to deduce during the pairing procedure, do not use in production.

Does Nordic provide sample code for pairing without passkey?

[Einarh]

Hello

I think you have misunderstood what this warning means.

It isn't telling you to not use a passkey, it is telling you to not use a fixed passkey. 

Instead you should use a unique randomized passkey, which should be default if you haven't set CONFIG_BT_FIXED_PASSKEY.

Best regards,

Einar

[snowuyl]

Thanks for your reply! I use nRF Connect iOS APP to connect nRF5340 device. How does nRF Connect iOS APP know which passkey to enter if passkey is random generated?

[Einarh]

https://www.bluetooth.com/blog/bluetooth-pairing-passkey-entry/

[snowuyl]

Thanks for your reply! I can see the following description from URL you provided. However, my nRF5340 device doesn't have display capability. Does it mean fixed passkey is only solution for nRF5340 device without display capability?

If the IO capabilities of a device, either the initiating or responding device, has a display capability, then it will display a randomly generated passkey value between “000000” and “999999.”

[Einarh]

Then please have a look at this:

https://www.bluetooth.com/blog/bluetooth-pairing-part-1-pairing-feature-exchange/

[snowuyl]

Thanks for your reply! I can see the following description from URL you provided. My nRF5340 device belongs to NoInputNoOutput. Does the following description suggest no pairing or static pairing for NoInputNoOutput device?

None of the pairing algorithms can use Yes/No input and no output, therefore, “NoInputNoOutput” is used as the resulting IO capability.

[Einarh]

No it does not suggest anything like that, this sentence only clarifies the corresponding table.

Please read the whole document.

[snowuyl]

What is your pairing suggestion for NoInputNoOutput device?

[Einarh]

https://www.bluetooth.com/blog/bluetooth-pairing-part-2-key-generation-methods/

[snowuyl]

Thanks for your reply! I can see the following description from URL you provided. What is meaning of "Just works unauthenticated"?

Step 4: Below is a mapping of the IO Capabilities to Key Generation Method. With this table, both devices, initiator and responder, will find an appropriate method for connecting depending on their pairing features.
Just works unauthenticated

[Einarh]

https://academy.nordicsemi.com/topic/security-models/

In most cases "just works" is the default BLE pairing method. Unless you have activated something else, your BLE device probably uses "just works".

You can read more about how it works in detail here:

https://lembergsolutions.com/blog/how-secure-ble-communication-standard

-Einar